还需要补充什么
要填坑
1，View绘制流程(坑2-2)；
2，事件分发时序图 (坑1-8)，新开篇四；
3，Activity启动时序图(坑2-6)；
4，常用第三方框架的设计模式：RxJava,Glide等(坑1-22)；
5，算法(坑2-3)；
6，二十三种设计模式(坑2-5)；
7，内存及电量优化(坑1-14,1-21)；
Android的三大问题，Handler消息机制，事件分发机制，View绘制流程；
把这仨先梳理好了。。。。
消息机制(1-5)，没啥能说的了。
事件分发机制(1-8)，再补个时序图，贴回(1-8)。
这篇就专门划拉View绘制流程吧。
SO，Mail的名字有了。
都是被人翻烂了的东西。。。。
先回顾(2-2)的自定义View。
两种形态，继承自View及继承自ViewGroup。
2019年05月22日15:21:35
拉之前的demo过来
1，继承自View的自定义View
不要在意细节问题，只看思路
package dc.test.surname.shi; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.support.annotation.Nullable; import android.util.AttributeSet; import android.view.View; import dc.test.surname.R; /** * @author senrsl * @ClassName: ShapeView * @Package: dc.test.surname.shi * @CreateTime: 2019/5/10 2:17 PM */ public class ShapeView extends View { private int defalutSize; public ShapeView(Context context) { super(context); } public ShapeView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); //第二个参数就是我们在styles.xml文件中的<declare-styleable>标签 //即属性集合的标签，在R文件中名称为R.styleable+name TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.ShapeView); //第一个参数为属性集合里面的属性，R文件名称：R.styleable+属性集合名称+下划线+属性名称 //第二个参数为，如果没有设置这个属性，则设置的默认的值 defalutSize = array.getDimensionPixelSize(R.styleable.ShapeView_default_size, 10); //最后记得将TypedArray对象回收 array.recycle(); } private int getLastSize(int defaultSize, int measureSpec) { int lastSize = defaultSize; int mode = MeasureSpec.getMode(measureSpec); int size = MeasureSpec.getSize(measureSpec); //根据模式不同，来确定最终大小 switch (mode) { case MeasureSpec.UNSPECIFIED: //父容器没有对当前View有任何限制，当前View可以任意取尺寸 lastSize = defaultSize;//如果没有指定大小，就设置为默认大小 break; case MeasureSpec.AT_MOST: //当前尺寸是当前View能取的最大尺寸,如wrap_content lastSize = size;//我们将大小取最大值,你也可以取其他值 break; case MeasureSpec.EXACTLY: //当前的尺寸就是当前View应该取的尺寸 lastSize = size;//如果是固定的大小，那就不要去改变它 break; } return lastSize; } /** * 1，测量尺寸 * * @param widthMeasureSpec * @param heightMeasureSpec */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int width = getLastSize(defalutSize, widthMeasureSpec); int height = getLastSize(defalutSize, heightMeasureSpec); if (width < height) { height = width; } else { width = height; } setMeasuredDimension(width, height); } /** * 2，摆放 * 一般是父ViewGroup调用子View摆放 * * @param changed * @param left * @param top * @param right * @param bottom */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); } /** * 3，绘制 * * @param canvas */ @Override protected void onDraw(Canvas canvas) { //调用父View的onDraw函数，因为View这个类帮我们实现了一些 基本的而绘制功能，比如绘制背景颜色、背景图片等 super.onDraw(canvas); int r = getMeasuredWidth() / 2;//半径 int centerX = r;//圆心的横坐标 int centerY = r; //圆心的纵坐标 Paint paint = new Paint();//画笔应该在构造函数创建，不要在这里new paint.setColor(Color.BLUE); canvas.drawCircle(centerX, centerY, r, paint);//画圆 } }
2，继承自ViewGroup的自定义View
package dc.test.surname.shi; import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; /** * @author senrsl * @ClassName: ShapeViewGroup * @Package: dc.test.surname.shi * @CreateTime: 2019/5/10 2:50 PM */ public class ShapeViewGroup extends ViewGroup { public ShapeViewGroup(Context context) { super(context); } public ShapeViewGroup(Context context, AttributeSet attrs) { super(context, attrs); } /*** * 获取子View中宽度最大的值 */ private int getMaxChildWidth() { int childCount = getChildCount(); int maxWidth = 0; for (int i = 0; i < childCount; i++) { View childView = getChildAt(i); if (childView.getMeasuredWidth() > maxWidth) maxWidth = childView.getMeasuredWidth(); } return maxWidth; } /*** * 将所有子View的高度相加 **/ private int getTotleHeight() { int childCount = getChildCount(); int height = 0; for (int i = 0; i < childCount; i++) { View childView = getChildAt(i); height += childView.getMeasuredHeight(); } return height; } /** * 1,测量 * * @param widthMeasureSpec * @param heightMeasureSpec */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); //将所有的子View进行测量，这会触发每个子View的onMeasure函数 //注意要与measureChild区分，measureChild是对单个view进行测量 measureChildren(widthMeasureSpec, heightMeasureSpec); int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int childCount = getChildCount(); if (childCount == 0) {//如果没有子View,当前ViewGroup没有存在的意义，不用占用空间 setMeasuredDimension(0, 0); } else { //如果宽高都是包裹内容 if (widthMode == MeasureSpec.AT_MOST && heightMode == MeasureSpec.AT_MOST) { int height = getTotleHeight();//高度设置为所有子View的高度相加 int width = getMaxChildWidth();//宽度设为子View中最大的宽度 setMeasuredDimension(width, height); } else if (heightMode == MeasureSpec.AT_MOST) {//如果只有高度是包裹内容 setMeasuredDimension(widthSize, getTotleHeight());//宽度设置为ViewGroup自己的测量宽度，高度设置为所有子View的高度总和 } else if (widthMode == MeasureSpec.AT_MOST) {//如果只有宽度是包裹内容 setMeasuredDimension(getMaxChildWidth(), heightSize);////宽度设置为子View中宽度最大的值，高度设置为ViewGroup自己的测量值 } } } /** * 2,摆放 * * @param changed * @param left * @param top * @param right * @param bottom */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { int count = getChildCount(); int curHeight = 0;//记录当前的高度位置 //将子View逐个摆放 for (int i = 0; i < count; i++) { View child = getChildAt(i); int height = child.getMeasuredHeight(); int width = child.getMeasuredWidth(); //摆放子View，参数分别是子View矩形区域的左、上、右、下边 //onLayout方法中子View调用的方法layout(l,t,r,b)四个参数的值是以ViewGroup的左上角的点为坐标原点(y轴向下),而不应该用onLayout方法参数里的值 child.layout(left, curHeight, left + width, curHeight + height); curHeight += height; } } /** * 3，绘制 * * @param canvas */ @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); } }
基本流程一样，都是测量、摆放、绘制；
其中ViewGroup是要对所有子View进行调用；
3，xml布局是怎么解析成View(**显示到屏幕上**)的
2022年06月02日15:36:25
Activity.onCreate()中调用setContextView(viewId)方法，设置当前页面布局。
实际调用到Activity.setContenxtView(layoutId)
/** View绘制布局入口 01 * Set the activity content from a layout resource. The resource will be * inflated, adding all top-level views to the activity.从布局资源中设置活动内容。 资源将被膨胀，将所有顶级视图添加到活动中。 * * @param layoutResID Resource ID to be inflated. * * @see #setContentView(android.view.View) * @see #setContentView(android.view.View, android.view.ViewGroup.LayoutParams) */ public void setContentView(@LayoutRes int layoutResID) { getWindow().setContentView(layoutResID); initWindowDecorActionBar(); }
其中getWindow()取到的mWindow变量是
abstract class Window
实际是在Activity.attach方法中填充的是PhoneWindow
final void attach(Context context, ActivityThread aThread, Instrumentation instr, IBinder token, int ident, Application application, Intent intent, ActivityInfo info, CharSequence title, Activity parent, String id, NonConfigurationInstances lastNonConfigurationInstances, Configuration config, String referrer, IVoiceInteractor voiceInteractor, Window window, ActivityConfigCallback activityConfigCallback) { attachBaseContext(context); mFragments.attachHost(null /*parent*/); mWindow = new PhoneWindow(this, window, activityConfigCallback); //View绘制布局2 new Window() mWindow.setWindowControllerCallback(this); mWindow.setCallback(this); mWindow.setOnWindowDismissedCallback(this); mWindow.getLayoutInflater().setPrivateFactory(this); if (info.softInputMode != WindowManager.LayoutParams.SOFT_INPUT_STATE_UNSPECIFIED) { mWindow.setSoftInputMode(info.softInputMode); } if (info.uiOptions != 0) { mWindow.setUiOptions(info.uiOptions); } mUiThread = Thread.currentThread(); mMainThread = aThread; mInstrumentation = instr; mToken = token; mIdent = ident; mApplication = application; mIntent = intent; mReferrer = referrer; mComponent = intent.getComponent(); mActivityInfo = info; mTitle = title; mParent = parent; mEmbeddedID = id; mLastNonConfigurationInstances = lastNonConfigurationInstances; if (voiceInteractor != null) { if (lastNonConfigurationInstances != null) { mVoiceInteractor = lastNonConfigurationInstances.voiceInteractor; } else { mVoiceInteractor = new VoiceInteractor(voiceInteractor, this, this, Looper.myLooper()); } } mWindow.setWindowManager( (WindowManager)context.getSystemService(Context.WINDOW_SERVICE), mToken, mComponent.flattenToString(), (info.flags & ActivityInfo.FLAG_HARDWARE_ACCELERATED) != 0); if (mParent != null) { mWindow.setContainer(mParent.getWindow()); } mWindowManager = mWindow.getWindowManager(); mCurrentConfig = config; mWindow.setColorMode(info.colorMode); setAutofillCompatibilityEnabled(application.isAutofillCompatibilityEnabled()); enableAutofillCompatibilityIfNeeded(); }
然后调用Window的方法去setContextView
window的抽象方法
/** * Convenience for * {@link #setContentView(View, android.view.ViewGroup.LayoutParams)} * to set the screen content from a layout resource. The resource will be * inflated, adding all top-level views to the screen. * * @param layoutResID Resource ID to be inflated. * @see #setContentView(View, android.view.ViewGroup.LayoutParams) */ public abstract void setContentView(@LayoutRes int layoutResID);
实际实现还是PhoneWindow.setContextView
//View绘制布局3 PhoneWindow实现 @Override public void setContentView(int layoutResID) { // Note: FEATURE_CONTENT_TRANSITIONS may be set in the process of installing the window // decor, when theme attributes and the like are crystalized. Do not check the feature // before this happens. if (mContentParent == null) { installDecor();//创建Decor } else if (!hasFeature(FEATURE_CONTENT_TRANSITIONS)) { mContentParent.removeAllViews(); } if (hasFeature(FEATURE_CONTENT_TRANSITIONS)) { final Scene newScene = Scene.getSceneForLayout(mContentParent, layoutResID, getContext()); transitionTo(newScene); } else { mLayoutInflater.inflate(layoutResID, mContentParent); //不用显示动画就直接添加 } mContentParent.requestApplyInsets(); final Callback cb = getCallback(); if (cb != null && !isDestroyed()) { cb.onContentChanged(); } mContentParentExplicitlySet = true; }
先创建关联了DecorView()，给DecorView的PhoneWindow变量做了关联。
补充：创建DecorView
在PhoneWindow.setContentView()时会创建install DecorView
其中DecorView定义在PhoneWindow变量
// This is the top-level view of the window, containing the window decor.这是窗口的顶层视图，包含窗口装饰。 private DecorView mDecor;
简单的描述创建
private void installDecor() { mForceDecorInstall = false; if (mDecor == null) { mDecor = generateDecor(-1); mDecor.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS); mDecor.setIsRootNamespace(true); if (!mInvalidatePanelMenuPosted && mInvalidatePanelMenuFeatures != 0) { mDecor.postOnAnimation(mInvalidatePanelMenuRunnable); } } else { mDecor.setWindow(this); } if (mContentParent == null) { mContentParent = generateLayout(mDecor); // Set up decor part of UI to ignore fitsSystemWindows if appropriate. mDecor.makeOptionalFitsSystemWindows(); final DecorContentParent decorContentParent = (DecorContentParent) mDecor.findViewById( R.id.decor_content_parent); if (decorContentParent != null) { mDecorContentParent = decorContentParent; mDecorContentParent.setWindowCallback(getCallback()); if (mDecorContentParent.getTitle() == null) { mDecorContentParent.setWindowTitle(mTitle); } final int localFeatures = getLocalFeatures(); for (int i = 0; i < FEATURE_MAX; i++) { if ((localFeatures & (1 << i)) != 0) { mDecorContentParent.initFeature(i); } } mDecorContentParent.setUiOptions(mUiOptions); if ((mResourcesSetFlags & FLAG_RESOURCE_SET_ICON) != 0 || (mIconRes != 0 && !mDecorContentParent.hasIcon())) { mDecorContentParent.setIcon(mIconRes); } else if ((mResourcesSetFlags & FLAG_RESOURCE_SET_ICON) == 0 && mIconRes == 0 && !mDecorContentParent.hasIcon()) { mDecorContentParent.setIcon( getContext().getPackageManager().getDefaultActivityIcon()); mResourcesSetFlags |= FLAG_RESOURCE_SET_ICON_FALLBACK; } if ((mResourcesSetFlags & FLAG_RESOURCE_SET_LOGO) != 0 || (mLogoRes != 0 && !mDecorContentParent.hasLogo())) { mDecorContentParent.setLogo(mLogoRes); } // Invalidate if the panel menu hasn't been created before this. // Panel menu invalidation is deferred avoiding application onCreateOptionsMenu // being called in the middle of onCreate or similar. // A pending invalidation will typically be resolved before the posted message // would run normally in order to satisfy instance state restoration. PanelFeatureState st = getPanelState(FEATURE_OPTIONS_PANEL, false); if (!isDestroyed() && (st == null || st.menu == null) && !mIsStartingWindow) { invalidatePanelMenu(FEATURE_ACTION_BAR); } } else { mTitleView = findViewById(R.id.title); if (mTitleView != null) { if ((getLocalFeatures() & (1 << FEATURE_NO_TITLE)) != 0) { final View titleContainer = findViewById(R.id.title_container); if (titleContainer != null) { titleContainer.setVisibility(View.GONE); } else { mTitleView.setVisibility(View.GONE); } mContentParent.setForeground(null); } else { mTitleView.setText(mTitle); } } } if (mDecor.getBackground() == null && mBackgroundFallbackResource != 0) { mDecor.setBackgroundFallback(mBackgroundFallbackResource); } // Only inflate or create a new TransitionManager if the caller hasn't // already set a custom one. if (hasFeature(FEATURE_ACTIVITY_TRANSITIONS)) { if (mTransitionManager == null) { final int transitionRes = getWindowStyle().getResourceId( R.styleable.Window_windowContentTransitionManager, 0); if (transitionRes != 0) { final TransitionInflater inflater = TransitionInflater.from(getContext()); mTransitionManager = inflater.inflateTransitionManager(transitionRes, mContentParent); } else { mTransitionManager = new TransitionManager(); } } mEnterTransition = getTransition(mEnterTransition, null, R.styleable.Window_windowEnterTransition); mReturnTransition = getTransition(mReturnTransition, USE_DEFAULT_TRANSITION, R.styleable.Window_windowReturnTransition); mExitTransition = getTransition(mExitTransition, null, R.styleable.Window_windowExitTransition); mReenterTransition = getTransition(mReenterTransition, USE_DEFAULT_TRANSITION, R.styleable.Window_windowReenterTransition); mSharedElementEnterTransition = getTransition(mSharedElementEnterTransition, null, R.styleable.Window_windowSharedElementEnterTransition); mSharedElementReturnTransition = getTransition(mSharedElementReturnTransition, USE_DEFAULT_TRANSITION, R.styleable.Window_windowSharedElementReturnTransition); mSharedElementExitTransition = getTransition(mSharedElementExitTransition, null, R.styleable.Window_windowSharedElementExitTransition); mSharedElementReenterTransition = getTransition(mSharedElementReenterTransition, USE_DEFAULT_TRANSITION, R.styleable.Window_windowSharedElementReenterTransition); if (mAllowEnterTransitionOverlap == null) { mAllowEnterTransitionOverlap = getWindowStyle().getBoolean( R.styleable.Window_windowAllowEnterTransitionOverlap, true); } if (mAllowReturnTransitionOverlap == null) { mAllowReturnTransitionOverlap = getWindowStyle().getBoolean( R.styleable.Window_windowAllowReturnTransitionOverlap, true); } if (mBackgroundFadeDurationMillis < 0) { mBackgroundFadeDurationMillis = getWindowStyle().getInteger( R.styleable.Window_windowTransitionBackgroundFadeDuration, DEFAULT_BACKGROUND_FADE_DURATION_MS); } if (mSharedElementsUseOverlay == null) { mSharedElementsUseOverlay = getWindowStyle().getBoolean( R.styleable.Window_windowSharedElementsUseOverlay, true); } } } }
直接在PhoneWindow中new对象产生
protected DecorView generateDecor(int featureId) { // System process doesn't have application context and in that case we need to directly use // the context we have. Otherwise we want the application context, so we don't cling to the // activity. Context context; if (mUseDecorContext) { Context applicationContext = getContext().getApplicationContext(); if (applicationContext == null) { context = getContext(); } else { context = new DecorContext(applicationContext, getContext()); if (mTheme != -1) { context.setTheme(mTheme); } } } else { context = getContext(); } return new DecorView(context, featureId, this, getAttributes()); }
补充DecorView创建完毕 2022年06月03日21:17:10
然后直接开始inflate
mLayoutInflater.inflate(layoutResID, mContentParent); //不用显示动画就直接添加
到了LayoutInflater类
/** //View绘制布局4 * Inflate a new view hierarchy from the specified xml resource.从指定的 xml 资源扩充新的视图层次结构。 Throws * {@link InflateException} if there is an error. * * @param resource ID for an XML layout resource to load (e.g., * <code>R.layout.main_page</code>) * @param root Optional view to be the parent of the generated hierarchy. * @return The root View of the inflated hierarchy. If root was supplied, * this is the root View; otherwise it is the root of the inflated * XML file. */ public View inflate(@LayoutRes int resource, @Nullable ViewGroup root) { return inflate(resource, root, root != null); }
先parse xml，然后inflate
/** * Inflate a new view hierarchy from the specified xml resource. Throws * {@link InflateException} if there is an error. * * @param resource ID for an XML layout resource to load (e.g., * <code>R.layout.main_page</code>) * @param root Optional view to be the parent of the generated hierarchy (if * <em>attachToRoot</em> is true), or else simply an object that * provides a set of LayoutParams values for root of the returned * hierarchy (if <em>attachToRoot</em> is false.) * @param attachToRoot Whether the inflated hierarchy should be attached to * the root parameter? If false, root is only used to create the * correct subclass of LayoutParams for the root view in the XML. * @return The root View of the inflated hierarchy. If root was supplied and * attachToRoot is true, this is root; otherwise it is the root of * the inflated XML file. */ public View inflate(@LayoutRes int resource, @Nullable ViewGroup root, boolean attachToRoot) { final Resources res = getContext().getResources(); if (DEBUG) { Log.d(TAG, "INFLATING from resource: \"" + res.getResourceName(resource) + "\" (" + Integer.toHexString(resource) + ")"); } final XmlResourceParser parser = res.getLayout(resource); //读取xml到xml解析器 try { return inflate(parser, root, attachToRoot);//View绘制布局5 } finally { parser.close(); } }
然后把xml转换为View
/** * Inflate a new view hierarchy from the specified XML node. Throws * {@link InflateException} if there is an error. * <p> * <em><strong>Important</strong></em> For performance * reasons, view inflation relies heavily on pre-processing of XML files * that is done at build time. Therefore, it is not currently possible to * use LayoutInflater with an XmlPullParser over a plain XML file at runtime. * * @param parser XML dom node containing the description of the view * hierarchy. * @param root Optional view to be the parent of the generated hierarchy (if * <em>attachToRoot</em> is true), or else simply an object that * provides a set of LayoutParams values for root of the returned * hierarchy (if <em>attachToRoot</em> is false.) * @param attachToRoot Whether the inflated hierarchy should be attached to * the root parameter? If false, root is only used to create the * correct subclass of LayoutParams for the root view in the XML. * @return The root View of the inflated hierarchy. If root was supplied and * attachToRoot is true, this is root; otherwise it is the root of * the inflated XML file. */ public View inflate(XmlPullParser parser, @Nullable ViewGroup root, boolean attachToRoot) { synchronized (mConstructorArgs) { Trace.traceBegin(Trace.TRACE_TAG_VIEW, "inflate"); final Context inflaterContext = mContext; final AttributeSet attrs = Xml.asAttributeSet(parser); Context lastContext = (Context) mConstructorArgs[0]; mConstructorArgs[0] = inflaterContext; View result = root; try { // Look for the root node. int type; while ((type = parser.next()) != XmlPullParser.START_TAG && type != XmlPullParser.END_DOCUMENT) { // Empty xml的开始或结束标记 } if (type != XmlPullParser.START_TAG) { throw new InflateException(parser.getPositionDescription() + ": No start tag found!"); } final String name = parser.getName(); if (DEBUG) { System.out.println("**************************"); System.out.println("Creating root view: " + name); System.out.println("**************************"); } if (TAG_MERGE.equals(name)) { if (root == null || !attachToRoot) { throw new InflateException("<merge /> can be used only with a valid " + "ViewGroup root and attachToRoot=true"); } rInflate(parser, root, inflaterContext, attrs, false); //merge标签传入的parent是rootView } else { // Temp is the root view that was found in the xml Temp 是在 xml 中找到的根视图 final View temp = createViewFromTag(root, name, inflaterContext, attrs); ViewGroup.LayoutParams params = null; if (root != null) { if (DEBUG) { System.out.println("Creating params from root: " + root); } // Create layout params that match root, if supplied 默认使用rootView的 layoutParams params = root.generateLayoutParams(attrs); if (!attachToRoot) { // Set the layout params for temp if we are not // attaching. (If we are, we use addView, below) temp.setLayoutParams(params); } } if (DEBUG) { System.out.println("-----> start inflating children"); } // Inflate all children under temp against its context. 递归inflate所有子View rInflateChildren(parser, temp, attrs, true); //View绘制布局6 if (DEBUG) { System.out.println("-----> done inflating children"); } // We are supposed to attach all the views we found (int temp) // to root. Do that now. 把所有找到的view都加入到root下 if (root != null && attachToRoot) { root.addView(temp, params); } // Decide whether to return the root that was passed in or the // top view found in xml. if (root == null || !attachToRoot) { result = temp; } } } catch (XmlPullParserException e) { final InflateException ie = new InflateException(e.getMessage(), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } catch (Exception e) { final InflateException ie = new InflateException(parser.getPositionDescription() + ": " + e.getMessage(), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } finally { // Don't retain static reference on context. mConstructorArgs[0] = lastContext; mConstructorArgs[1] = null; Trace.traceEnd(Trace.TRACE_TAG_VIEW); } return result; } }
递归inflate所有子View
/** * Recursive method used to inflate internal (non-root) children. This * method calls through to {@link #rInflate} using the parent context as * the inflation context. * <strong>Note:</strong> Default visibility so the BridgeInflater can * call it.用于膨胀内部（非根）子级的递归方法。 此方法使用父上下文作为膨胀上下文调用 {@link #rInflate}。 * 注意：默认可见性，以便 BridgeInflater 可以调用它。 */ final void rInflateChildren(XmlPullParser parser, View parent, AttributeSet attrs, boolean finishInflate) throws XmlPullParserException, IOException { rInflate(parser, parent, parent.getContext(), attrs, finishInflate); } /** * Recursive method used to descend down the xml hierarchy and instantiate * views, instantiate their children, and then call onFinishInflate(). * <p> * <strong>Note:</strong> Default visibility so the BridgeInflater can * override it. */ void rInflate(XmlPullParser parser, View parent, Context context, AttributeSet attrs, boolean finishInflate) throws XmlPullParserException, IOException { final int depth = parser.getDepth(); //深度 int type; boolean pendingRequestFocus = false; while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) { if (type != XmlPullParser.START_TAG) { continue; } final String name = parser.getName(); if (TAG_REQUEST_FOCUS.equals(name)) { //requestFocus属性 pendingRequestFocus = true; consumeChildElements(parser); } else if (TAG_TAG.equals(name)) { parseViewTag(parser, parent, attrs); } else if (TAG_INCLUDE.equals(name)) { if (parser.getDepth() == 0) { throw new InflateException("<include /> cannot be the root element"); } parseInclude(parser, context, parent, attrs);//include标签 } else if (TAG_MERGE.equals(name)) { throw new InflateException("<merge /> must be the root element"); } else { final View view = createViewFromTag(parent, name, context, attrs); //通过xml生成View final ViewGroup viewGroup = (ViewGroup) parent; final ViewGroup.LayoutParams params = viewGroup.generateLayoutParams(attrs); rInflateChildren(parser, view, attrs, true); viewGroup.addView(view, params); } } if (pendingRequestFocus) { parent.restoreDefaultFocus(); } if (finishInflate) { parent.onFinishInflate(); } }
然后去实际创建View
/** View绘制布局6 * Creates a view from a tag name using the supplied attribute set.使用提供的属性集从标记名称创建视图。 * <p> * <strong>Note:</strong> Default visibility so the BridgeInflater can * override it. * * @param parent the parent view, used to inflate layout params * @param name the name of the XML tag used to define the view * @param context the inflation context for the view, typically the * {@code parent} or base layout inflater context * @param attrs the attribute set for the XML tag used to define the view * @param ignoreThemeAttr {@code true} to ignore the {@code android:theme} * attribute (if set) for the view being inflated, * {@code false} otherwise */ View createViewFromTag(View parent, String name, Context context, AttributeSet attrs, boolean ignoreThemeAttr) { if (name.equals("view")) { name = attrs.getAttributeValue(null, "class");//解析 <view class="TextView"/>情况 } // Apply a theme wrapper, if allowed and one is specified. if (!ignoreThemeAttr) { final TypedArray ta = context.obtainStyledAttributes(attrs, ATTRS_THEME); final int themeResId = ta.getResourceId(0, 0); if (themeResId != 0) { context = new ContextThemeWrapper(context, themeResId); } ta.recycle(); } if (name.equals(TAG_1995)) { // Let's party like it's 1995! return new BlinkLayout(context, attrs); //创建<blink />闪烁布局 } try { View view; if (mFactory2 != null) { view = mFactory2.onCreateView(parent, name, context, attrs);//创建view Factory2 } else if (mFactory != null) { view = mFactory.onCreateView(name, context, attrs); //创建view Factory } else { view = null; } if (view == null && mPrivateFactory != null) { view = mPrivateFactory.onCreateView(parent, name, context, attrs);//创建view PrivateFactory } if (view == null) { final Object lastContext = mConstructorArgs[0]; mConstructorArgs[0] = context; try { if (-1 == name.indexOf('.')) { //xml 标签不带. view = onCreateView(parent, name, attrs);//创建view,android.view.XXX } else { view = createView(name, null, attrs);//创建带包名的view } } finally { mConstructorArgs[0] = lastContext; } } return view; } catch (InflateException e) { throw e; } catch (ClassNotFoundException e) { final InflateException ie = new InflateException(attrs.getPositionDescription() + ": Error inflating class " + name, e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } catch (Exception e) { final InflateException ie = new InflateException(attrs.getPositionDescription() + ": Error inflating class " + name, e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } }
先走Factory创建View，失败再反射创建
//View绘制布局7 public interface Factory { /** * Hook you can supply that is called when inflating from a LayoutInflater. * You can use this to customize the tag names available in your XML * layout files.您可以提供从 LayoutInflater 充气时调用的钩子。 * 您可以使用它来自定义 XML 布局文件中可用的标签名称。 * * <p> * Note that it is good practice to prefix these custom names with your * package (i.e., com.coolcompany.apps) to avoid conflicts with system * names. * * @param name Tag name to be inflated. * @param context The context the view is being created in. * @param attrs Inflation attributes as specified in XML file. * * @return View Newly created view. Return null for the default * behavior. */ public View onCreateView(String name, Context context, AttributeSet attrs); } public interface Factory2 extends Factory { /** * Version of {@link #onCreateView(String, Context, AttributeSet)} * that also supplies the parent that the view created view will be * placed in. * * @param parent The parent that the created view will be placed * in; <em>note that this may be null</em>. * @param name Tag name to be inflated. * @param context The context the view is being created in. * @param attrs Inflation attributes as specified in XML file. * * @return View Newly created view. Return null for the default * behavior. */ public View onCreateView(View parent, String name, Context context, AttributeSet attrs); } private static class FactoryMerger implements Factory2 { private final Factory mF1, mF2; private final Factory2 mF12, mF22; FactoryMerger(Factory f1, Factory2 f12, Factory f2, Factory2 f22) { mF1 = f1; mF2 = f2; mF12 = f12; mF22 = f22; } public View onCreateView(String name, Context context, AttributeSet attrs) { View v = mF1.onCreateView(name, context, attrs); if (v != null) return v; return mF2.onCreateView(name, context, attrs); } public View onCreateView(View parent, String name, Context context, AttributeSet attrs) { View v = mF12 != null ? mF12.onCreateView(parent, name, context, attrs) : mF1.onCreateView(name, context, attrs); if (v != null) return v; return mF22 != null ? mF22.onCreateView(parent, name, context, attrs) : mF2.onCreateView(name, context, attrs); } }
Factory实际执行的的是FactoryMerger
/** * Attach a custom Factory interface for creating views while using * this LayoutInflater. This must not be null, and can only be set once; * after setting, you can not change the factory. This is * called on each element name as the xml is parsed. If the factory returns * a View, that is added to the hierarchy. If it returns null, the next * factory default {@link #onCreateView} method is called. * * <p>If you have an existing * LayoutInflater and want to add your own factory to it, use * {@link #cloneInContext} to clone the existing instance and then you * can use this function (once) on the returned new instance. This will * merge your own factory with whatever factory the original instance is * using. */ public void setFactory(Factory factory) { if (mFactorySet) { throw new IllegalStateException("A factory has already been set on this LayoutInflater"); } if (factory == null) { throw new NullPointerException("Given factory can not be null"); } mFactorySet = true; if (mFactory == null) { mFactory = factory; } else { mFactory = new FactoryMerger(factory, null, mFactory, mFactory2); } } /** * Like {@link #setFactory}, but allows you to set a {@link Factory2} * interface. */ public void setFactory2(Factory2 factory) { if (mFactorySet) { throw new IllegalStateException("A factory has already been set on this LayoutInflater"); } if (factory == null) { throw new NullPointerException("Given factory can not be null"); } mFactorySet = true; if (mFactory == null) { mFactory = mFactory2 = factory; } else { mFactory = mFactory2 = new FactoryMerger(factory, factory, mFactory, mFactory2); } } /** * @hide for use by framework */ public void setPrivateFactory(Factory2 factory) { if (mPrivateFactory == null) { mPrivateFactory = factory; } else { mPrivateFactory = new FactoryMerger(factory, factory, mPrivateFactory, mPrivateFactory); } }
FactoryMerger只是做了Factory、Factory2的区分。。。。
private static class FactoryMerger implements Factory2 { private final Factory mF1, mF2; private final Factory2 mF12, mF22; FactoryMerger(Factory f1, Factory2 f12, Factory f2, Factory2 f22) { mF1 = f1; mF2 = f2; mF12 = f12; mF22 = f22; } public View onCreateView(String name, Context context, AttributeSet attrs) { View v = mF1.onCreateView(name, context, attrs); if (v != null) return v; return mF2.onCreateView(name, context, attrs); } public View onCreateView(View parent, String name, Context context, AttributeSet attrs) { View v = mF12 != null ? mF12.onCreateView(parent, name, context, attrs) : mF1.onCreateView(name, context, attrs); if (v != null) return v; return mF22 != null ? mF22.onCreateView(parent, name, context, attrs) : mF2.onCreateView(name, context, attrs); } }
Factory实际是通过上面的public set方法去赋值的。。。。
Factory失败，就通过反射创建View，
先判断xml tag是不是系统的View，如果是就加上系统包名
/** View绘制布局8 * This routine is responsible for creating the correct subclass of View * given the xmView绘制布局6l element name. Override it to handle custom view objects. If * you override this in your subclass be sure to call through to * super.onCreateView(name) for names you do not recognize. * * @param name The fully qualified class name of the View to be create. * @param attrs An AttributeSet of attributes to apply to the View. * * @return View The View created. */ protected View onCreateView(String name, AttributeSet attrs) throws ClassNotFoundException { return createView(name, "android.view.", attrs);//android系统view,添加包名 }
有了全部的类路径，就可以调用LayoutInflater.createView()方法，通过反射来创建实例了。。。。
/** View绘制布局9 * Low-level function for instantiating a view by name按名称实例化view的低等级方法. This attempts to * instantiate a view class of the given <var>name</var> found in this * LayoutInflater's ClassLoader. * * <p> * There are two things that can happen in an error case: either the * exception describing the error will be thrown, or a null will be * returned. You must deal with both possibilities -- the former will happen * the first time createView() is called for a class of a particular name, * the latter every time there-after for that class name. * * @param name The full name of the class to be instantiated. * @param attrs The XML attributes supplied for this instance. * * @return View The newly instantiated view, or null. */ public final View createView(String name, String prefix, AttributeSet attrs) throws ClassNotFoundException, InflateException { Constructor<? extends View> constructor = sConstructorMap.get(name);//从HashMap缓存里取 if (constructor != null && !verifyClassLoader(constructor)) { constructor = null; sConstructorMap.remove(name); } Class<? extends View> clazz = null; try { Trace.traceBegin(Trace.TRACE_TAG_VIEW, name); if (constructor == null) { // Class not found in the cache缓存里没有, see if it's real, and try to add it clazz = mContext.getClassLoader().loadClass( prefix != null ? (prefix + name) : name).asSubclass(View.class);//加载对应的类 if (mFilter != null && clazz != null) { boolean allowed = mFilter.onLoadClass(clazz); if (!allowed) { failNotAllowed(name, prefix, attrs); } } constructor = clazz.getConstructor(mConstructorSignature); //反射获取构造函数 constructor.setAccessible(true); sConstructorMap.put(name, constructor); //HashMap缓存 } else { // If we have a filter, apply it to cached constructor 缓存里有 if (mFilter != null) { // Have we seen this name before? Boolean allowedState = mFilterMap.get(name); if (allowedState == null) { // New class -- remember whether it is allowed clazz = mContext.getClassLoader().loadClass( prefix != null ? (prefix + name) : name).asSubclass(View.class); boolean allowed = clazz != null && mFilter.onLoadClass(clazz); mFilterMap.put(name, allowed); if (!allowed) { failNotAllowed(name, prefix, attrs); } } else if (allowedState.equals(Boolean.FALSE)) { failNotAllowed(name, prefix, attrs); } } } Object lastContext = mConstructorArgs[0]; if (mConstructorArgs[0] == null) { // Fill in the context if not already within inflation. mConstructorArgs[0] = mContext; } Object[] args = mConstructorArgs; args[1] = attrs; final View view = constructor.newInstance(args);//反射创建 if (view instanceof ViewStub) { //处理ViewStub // Use the same context when inflating ViewStub later. final ViewStub viewStub = (ViewStub) view; viewStub.setLayoutInflater(cloneInContext((Context) args[0])); } mConstructorArgs[0] = lastContext; return view; } catch (NoSuchMethodException e) { final InflateException ie = new InflateException(attrs.getPositionDescription() + ": Error inflating class " + (prefix != null ? (prefix + name) : name), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } catch (ClassCastException e) { // If loaded class is not a View subclass final InflateException ie = new InflateException(attrs.getPositionDescription() + ": Class is not a View " + (prefix != null ? (prefix + name) : name), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } catch (ClassNotFoundException e) { // If loadClass fails, we should propagate the exception. throw e; } catch (Exception e) { final InflateException ie = new InflateException( attrs.getPositionDescription() + ": Error inflating class " + (clazz == null ? "<unknown>" : clazz.getName()), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } finally { Trace.traceEnd(Trace.TRACE_TAG_VIEW); } }
这样就把xml解析成View了。。。。
View生成了一个View数，然后加到(ViewGroup) parent;上
final View view = createViewFromTag(parent, name, context, attrs); //通过xml生成View final ViewGroup viewGroup = (ViewGroup) parent; final ViewGroup.LayoutParams params = viewGroup.generateLayoutParams(attrs); rInflateChildren(parser, view, attrs, true); viewGroup.addView(view, params);
变成了View树。。。。
怎么显示出来的呢？
那就是了，现在是onCreate()生命周期，是不显示的。。。。
总结起来，xml是怎么变成View的？
Activity.setContextView(layoutId)，方法内获取到PhoneWindow(Window)对象，PhoneWindow.setContextView(layoutId)方法，调用LayoutInflater.inflate()方法 ；
LayoutInflater.inflate()方法，通过XmlParser解析读取xml文件，遍历XML树，通过Factory或反射来创建View。
好像简单了点。。。。
4，View怎么显示到屏幕上
这一翻不要紧，原来几年前就分析完代码了，结果几年后费这么大劲。。。。
在创建Activity的时候，会调用onCreate()，创建DecorView，并将DecorView添加到Window中，同时会创建ViewRootImpl对象，并与DecorView建立关联。
从ActivityThread.handleLauncherActivity()开始
/** 绘制V1,从启动一个Activity的流程上，到了这里，开始创建Activity * Extended implementation of activity launch. Used when server requests a launch or relaunch.在server请求启动或重启动时，继承实现activity的启动 */ @Override public Activity handleLaunchActivity(ActivityClientRecord r, PendingTransactionActions pendingActions, Intent customIntent) { // If we are getting ready to gc after going to the background, well如果我们在前往后台后准备好gc，那么 // we are back active so skip it.我们回来了，所以跳过它。 unscheduleGcIdler(); mSomeActivitiesChanged = true; if (r.profilerInfo != null) { mProfiler.setProfiler(r.profilerInfo); mProfiler.startProfiling(); } // Make sure we are running with the most recent config.确保我们使用最新的配置运行 handleConfigurationChanged(null, null); if (localLOGV) Slog.v( TAG, "Handling launch of " + r); // Initialize before creating the activity if (!ThreadedRenderer.sRendererDisabled) { GraphicsEnvironment.earlyInitEGL(); } WindowManagerGlobal.initialize(); final Activity a = performLaunchActivity(r, customIntent);//创建Activity，会调用Activity的onCreate方法从而完成DecorView的创建 绘制VA1 if (a != null) { r.createdConfig = new Configuration(mConfiguration); reportSizeConfigurations(r); if (!r.activity.mFinished && pendingActions != null) { pendingActions.setOldState(r.state); pendingActions.setRestoreInstanceState(true); pendingActions.setCallOnPostCreate(true); } } else { // If there was an error, for any reason, tell the activity manager to stop us. try { ActivityManager.getService() .finishActivity(r.token, Activity.RESULT_CANCELED, null, Activity.DONT_FINISH_TASK_WITH_ACTIVITY); } catch (RemoteException ex) { throw ex.rethrowFromSystemServer(); } } return a; }
然后看实际创建 ActivityThread#performLaunchActivity方法
/** Core implementation of activity launch. */ private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) { ActivityInfo aInfo = r.activityInfo; if (r.packageInfo == null) { r.packageInfo = getPackageInfo(aInfo.applicationInfo, r.compatInfo, Context.CONTEXT_INCLUDE_CODE); } ComponentName component = r.intent.getComponent(); if (component == null) { component = r.intent.resolveActivity( mInitialApplication.getPackageManager()); r.intent.setComponent(component); } if (r.activityInfo.targetActivity != null) { component = new ComponentName(r.activityInfo.packageName, r.activityInfo.targetActivity); } ContextImpl appContext = createBaseContextForActivity(r); Activity activity = null; try { java.lang.ClassLoader cl = appContext.getClassLoader(); activity = mInstrumentation.newActivity( cl, component.getClassName(), r.intent); //绘制VA2 反射创建Activity对象 StrictMode.incrementExpectedActivityCount(activity.getClass()); r.intent.setExtrasClassLoader(cl); r.intent.prepareToEnterProcess(); if (r.state != null) { r.state.setClassLoader(cl); } } catch (Exception e) { if (!mInstrumentation.onException(activity, e)) { throw new RuntimeException( "Unable to instantiate activity " + component + ": " + e.toString(), e); } } try { Application app = r.packageInfo.makeApplication(false, mInstrumentation);//绘制VA3 反射创建Application if (localLOGV) Slog.v(TAG, "Performing launch of " + r); if (localLOGV) Slog.v( TAG, r + ": app=" + app + ", appName=" + app.getPackageName() + ", pkg=" + r.packageInfo.getPackageName() + ", comp=" + r.intent.getComponent().toShortString() + ", dir=" + r.packageInfo.getAppDir()); if (activity != null) { CharSequence title = r.activityInfo.loadLabel(appContext.getPackageManager()); Configuration config = new Configuration(mCompatConfiguration); if (r.overrideConfig != null) { config.updateFrom(r.overrideConfig); } if (DEBUG_CONFIGURATION) Slog.v(TAG, "Launching activity " + r.activityInfo.name + " with config " + config); Window window = null; if (r.mPendingRemoveWindow != null && r.mPreserveWindow) { window = r.mPendingRemoveWindow; r.mPendingRemoveWindow = null; r.mPendingRemoveWindowManager = null; } appContext.setOuterContext(activity); activity.attach(appContext, this, getInstrumentation(), r.token, r.ident, app, r.intent, r.activityInfo, title, r.parent, r.embeddedID, r.lastNonConfigurationInstances, config, r.referrer, r.voiceInteractor, window, r.configCallback); if (customIntent != null) { activity.mIntent = customIntent; } r.lastNonConfigurationInstances = null; checkAndBlockForNetworkAccess(); activity.mStartedActivity = false; int theme = r.activityInfo.getThemeResource(); if (theme != 0) { activity.setTheme(theme); } activity.mCalled = false; if (r.isPersistable()) { mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState); //绘制VA4 调用onCreate生命周期 } else { mInstrumentation.callActivityOnCreate(activity, r.state); } if (!activity.mCalled) { throw new SuperNotCalledException( "Activity " + r.intent.getComponent().toShortString() + " did not call through to super.onCreate()"); } r.activity = activity; } r.setState(ON_CREATE); mActivities.put(r.token, r); } catch (SuperNotCalledException e) { throw e; } catch (Exception e) { if (!mInstrumentation.onException(activity, e)) { throw new RuntimeException( "Unable to start activity " + component + ": " + e.toString(), e); } } return activity; }
Instrumentation创建Activity对象
/** * Perform instantiation of the process's {@link Activity} object. The * default implementation provides the normal system behavior. * * @param cl The ClassLoader with which to instantiate the object. * @param className The name of the class implementing the Activity * object. * @param intent The Intent object that specified the activity class being * instantiated. * * @return The newly instantiated Activity object. */ public Activity newActivity(ClassLoader cl, String className, Intent intent) throws InstantiationException, IllegalAccessException, ClassNotFoundException { String pkg = intent != null && intent.getComponent() != null ? intent.getComponent().getPackageName() : null; return getFactory(pkg).instantiateActivity(cl, className, intent); }
调用到了AppComponentFactory#instantiateActivity()反射创建
/** * Allows application to override the creation of activities. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * <p> * This method is only intended to provide a hook for instantiation. It does not provide * earlier access to the Activity object. The returned object will not be initialized * as a Context yet and should not be used to interact with other android APIs. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. * @param intent Intent creating the class. */ public @NonNull Activity instantiateActivity(@NonNull ClassLoader cl, @NonNull String className, @Nullable Intent intent) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (Activity) cl.loadClass(className).newInstance(); }
Application的创建也基本一样
调用LoadApk#makeApplication()方法
public Application makeApplication(boolean forceDefaultAppClass, Instrumentation instrumentation) { if (mApplication != null) { return mApplication; } Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "makeApplication"); Application app = null; String appClass = mApplicationInfo.className; if (forceDefaultAppClass || (appClass == null)) { appClass = "android.app.Application"; } try { java.lang.ClassLoader cl = getClassLoader(); if (!mPackageName.equals("android")) { Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "initializeJavaContextClassLoader"); initializeJavaContextClassLoader(); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); } ContextImpl appContext = ContextImpl.createAppContext(mActivityThread, this); app = mActivityThread.mInstrumentation.newApplication( cl, appClass, appContext); appContext.setOuterContext(app); } catch (Exception e) { if (!mActivityThread.mInstrumentation.onException(app, e)) { Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); throw new RuntimeException( "Unable to instantiate application " + appClass + ": " + e.toString(), e); } } mActivityThread.mAllApplications.add(app); mApplication = app; if (instrumentation != null) { try { instrumentation.callApplicationOnCreate(app); } catch (Exception e) { if (!instrumentation.onException(app, e)) { Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); throw new RuntimeException( "Unable to create application " + app.getClass().getName() + ": " + e.toString(), e); } } } // Rewrite the R 'constants' for all library apks. SparseArray<String> packageIdentifiers = getAssets().getAssignedPackageIdentifiers(); final int N = packageIdentifiers.size(); for (int i = 0; i < N; i++) { final int id = packageIdentifiers.keyAt(i); if (id == 0x01 || id == 0x7f) { continue; } rewriteRValues(getClassLoader(), packageIdentifiers.valueAt(i), id); } Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); return app; }
回到Instrumentation#newApplication()
/** * Perform instantiation of the process's {@link Application} object. The * default implementation provides the normal system behavior. * * @param cl The ClassLoader with which to instantiate the object. * @param className The name of the class implementing the Application * object. * @param context The context to initialize the application with * * @return The newly instantiated Application object. */ public Application newApplication(ClassLoader cl, String className, Context context) throws InstantiationException, IllegalAccessException, ClassNotFoundException { Application app = getFactory(context.getPackageName()) .instantiateApplication(cl, className); app.attach(context); return app; }
实际调用AppComponentFactory创建
/** * Allows application to override the creation of the application object. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * <p> * This method is only intended to provide a hook for instantiation. It does not provide * earlier access to the Application object. The returned object will not be initialized * as a Context yet and should not be used to interact with other android APIs. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. */ public @NonNull Application instantiateApplication(@NonNull ClassLoader cl, @NonNull String className) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (Application) cl.loadClass(className).newInstance(); }
然后发现 AppComponentFactory类，全是创建。。。。
/** * Interface used to control the instantiation of manifest elements. * * @see #instantiateApplication * @see #instantiateActivity * @see #instantiateService * @see #instantiateReceiver * @see #instantiateProvider */ public class AppComponentFactory { /** * Allows application to override the creation of the application object. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * <p> * This method is only intended to provide a hook for instantiation. It does not provide * earlier access to the Application object. The returned object will not be initialized * as a Context yet and should not be used to interact with other android APIs. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. */ public @NonNull Application instantiateApplication(@NonNull ClassLoader cl, @NonNull String className) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (Application) cl.loadClass(className).newInstance(); } /** * Allows application to override the creation of activities. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * <p> * This method is only intended to provide a hook for instantiation. It does not provide * earlier access to the Activity object. The returned object will not be initialized * as a Context yet and should not be used to interact with other android APIs. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. * @param intent Intent creating the class. */ public @NonNull Activity instantiateActivity(@NonNull ClassLoader cl, @NonNull String className, @Nullable Intent intent) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (Activity) cl.loadClass(className).newInstance(); } /** * Allows application to override the creation of receivers. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. * @param intent Intent creating the class. */ public @NonNull BroadcastReceiver instantiateReceiver(@NonNull ClassLoader cl, @NonNull String className, @Nullable Intent intent) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (BroadcastReceiver) cl.loadClass(className).newInstance(); } /** * Allows application to override the creation of services. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * <p> * This method is only intended to provide a hook for instantiation. It does not provide * earlier access to the Service object. The returned object will not be initialized * as a Context yet and should not be used to interact with other android APIs. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. * @param intent Intent creating the class. */ public @NonNull Service instantiateService(@NonNull ClassLoader cl, @NonNull String className, @Nullable Intent intent) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (Service) cl.loadClass(className).newInstance(); } /** * Allows application to override the creation of providers. This can be used to * perform things such as dependency injection or class loader changes to these * classes. * <p> * This method is only intended to provide a hook for instantiation. It does not provide * earlier access to the ContentProvider object. The returned object will not be initialized * with a Context yet and should not be used to interact with other android APIs. * * @param cl The default classloader to use for instantiation. * @param className The class to be instantiated. */ public @NonNull ContentProvider instantiateProvider(@NonNull ClassLoader cl, @NonNull String className) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return (ContentProvider) cl.loadClass(className).newInstance(); } /** * @hide */ public static final AppComponentFactory DEFAULT = new AppComponentFactory(); }
里面创建了四大组件。。。。
扯远了，回到View绘制。。。。
在Activity和Application创建后，Instrumentation会调用执行onCreate()，VA4
调用Instrumentation#callActivityOnCreate()
/** * Perform calling of an activity's {@link Activity#onCreate} * method. The default implementation simply calls through to that method. * @param activity The activity being created. * @param icicle The previously frozen state (or null) to pass through to * @param persistentState The previously persisted state (or null) */ public void callActivityOnCreate(Activity activity, Bundle icicle, PersistableBundle persistentState) { prePerformCreate(activity); activity.performCreate(icicle, persistentState); postPerformCreate(activity); }
调用Activity#performCreate()
final void performCreate(Bundle icicle, PersistableBundle persistentState) { mCanEnterPictureInPicture = true; restoreHasCurrentPermissionRequest(icicle); if (persistentState != null) { onCreate(icicle, persistentState); //绘制VA5 实际调用onCreate() } else { onCreate(icicle); } writeEventLog(LOG_AM_ON_CREATE_CALLED, "performCreate"); mActivityTransitionState.readState(icicle); mVisibleFromClient = !mWindow.getWindowStyle().getBoolean( com.android.internal.R.styleable.Window_windowNoDisplay, false); mFragments.dispatchActivityCreated(); mActivityTransitionState.setEnterActivityOptions(this, getActivityOptions()); }
实际执行onCreate()
/** 绘制VA6 实际调用onCreate() * Called when the activity is starting. This is where most initialization * should go: calling {@link #setContentView(int)} to inflate the * activity's UI, using {@link #findViewById} to programmatically interact * with widgets in the UI, calling * {@link #managedQuery(android.net.Uri , String[], String, String[], String)} to retrieve * cursors for data being displayed, etc. * * <p>You can call {@link #finish} from within this function, in * which case onDestroy() will be immediately called after {@link #onCreate} without any of the * rest of the activity lifecycle ({@link #onStart}, {@link #onResume}, {@link #onPause}, etc) * executing. * * <p><em>Derived classes must call through to the super class's * implementation of this method. If they do not, an exception will be * thrown.</em></p> * * @param savedInstanceState If the activity is being re-initialized after * previously being shut down then this Bundle contains the data it most * recently supplied in {@link #onSaveInstanceState}. <b><i>Note: Otherwise it is null.</i></b> * * @see #onStart * @see #onSaveInstanceState * @see #onRestoreInstanceState * @see #onPostCreate */ @MainThread @CallSuper protected void onCreate(@Nullable Bundle savedInstanceState) { if (DEBUG_LIFECYCLE) Slog.v(TAG, "onCreate " + this + ": " + savedInstanceState); if (mLastNonConfigurationInstances != null) { mFragments.restoreLoaderNonConfig(mLastNonConfigurationInstances.loaders); } if (mActivityInfo.parentActivityName != null) { if (mActionBar == null) { mEnableDefaultActionBarUp = true; } else { mActionBar.setDefaultDisplayHomeAsUpEnabled(true); } } if (savedInstanceState != null) { mAutoFillResetNeeded = savedInstanceState.getBoolean(AUTOFILL_RESET_NEEDED, false); mLastAutofillId = savedInstanceState.getInt(LAST_AUTOFILL_ID, View.LAST_APP_AUTOFILL_ID); if (mAutoFillResetNeeded) { getAutofillManager().onCreate(savedInstanceState); } Parcelable p = savedInstanceState.getParcelable(FRAGMENTS_TAG); mFragments.restoreAllState(p, mLastNonConfigurationInstances != null ? mLastNonConfigurationInstances.fragments : null); } mFragments.dispatchCreate(); getApplication().dispatchActivityCreated(this, savedInstanceState); if (mVoiceInteractor != null) { mVoiceInteractor.attachActivity(this); } mRestoredFromBundle = savedInstanceState != null; mCalled = true; }
handleLauncherActivity()方法，创建了Activity对象，调用onCreate()方法。。。。
然后准备绘制，绘制是在onResume()生命周期，开始于ActivityThread.handleResume()
//绘制V2,在activity#onResume()方法后，addView @Override public void handleResumeActivity(IBinder token, boolean finalStateRequest, boolean isForward, String reason) { // If we are getting ready to gc after going to the background, well // we are back active so skip it. unscheduleGcIdler(); mSomeActivitiesChanged = true; // TODO Push resumeArgs into the activity for consideration 调用Activity的onResume方法 final ActivityClientRecord r = performResumeActivity(token, finalStateRequest, reason); if (r == null) { // We didn't actually resume the activity, so skipping any follow-up actions. return; } final Activity a = r.activity; if (localLOGV) { Slog.v(TAG, "Resume " + r + " started activity: " + a.mStartedActivity + ", hideForNow: " + r.hideForNow + ", finished: " + a.mFinished); } final int forwardBit = isForward ? WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION : 0; // If the window hasn't yet been added to the window manager,如果窗口尚未添加到窗口管理器， // and this guy didn't finish itself or start another activity,而这个家伙没有完成自己或开始另一项活动， // then go ahead and add the window. 然后继续添加窗口。 boolean willBeVisible = !a.mStartedActivity; if (!willBeVisible) { try { willBeVisible = ActivityManager.getService().willActivityBeVisible( a.getActivityToken()); } catch (RemoteException e) { throw e.rethrowFromSystemServer(); } } if (r.window == null && !a.mFinished && willBeVisible) { r.window = r.activity.getWindow(); View decor = r.window.getDecorView(); //得到DecorView decor.setVisibility(View.INVISIBLE); ViewManager wm = a.getWindowManager(); // 得到了WindowManager，WindowManager是一个接口并且继承了接口ViewManager WindowManager.LayoutParams l = r.window.getAttributes(); a.mDecor = decor; l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION; l.softInputMode |= forwardBit; if (r.mPreserveWindow) { a.mWindowAdded = true; r.mPreserveWindow = false; // Normally the ViewRoot sets up callbacks with the Activity通常，ViewRoot会使用Activity设置回调 // in addView->ViewRootImpl#setView. If we are instead reusing在addView-> ViewRootImpl＃setView中。 如果我们反而重复使用 // the decor view we have to notify the view root that the装饰视图我们必须通知视图根 // callbacks may have changed. 回调可能已经改变。 ViewRootImpl impl = decor.getViewRootImpl(); if (impl != null) { impl.notifyChildRebuilt(); } } if (a.mVisibleFromClient) { if (!a.mWindowAdded) { a.mWindowAdded = true; wm.addView(decor, l); //WindowManager的实现类是WindowManagerImpl，所以实际调用的是WindowManagerImpl的addView方法 decor和LayoutParams } else { // The activity will get a callback for this {@link LayoutParams} change // earlier. However, at that time the decor will not be set (this is set // in this method), so no action will be taken. This call ensures the // callback occurs with the decor set. a.onWindowAttributesChanged(l); } } // If the window has already been added, but during resume // we started another activity, then don't yet make the // window visible. } else if (!willBeVisible) { if (localLOGV) Slog.v(TAG, "Launch " + r + " mStartedActivity set"); r.hideForNow = true; } // Get rid of anything left hanging around. cleanUpPendingRemoveWindows(r, false /* force */); // The window is now visible if it has been added, we are not // simply finishing, and we are not starting another activity. if (!r.activity.mFinished && willBeVisible && r.activity.mDecor != null && !r.hideForNow) { if (r.newConfig != null) { performConfigurationChangedForActivity(r, r.newConfig); if (DEBUG_CONFIGURATION) { Slog.v(TAG, "Resuming activity " + r.activityInfo.name + " with newConfig " + r.activity.mCurrentConfig); } r.newConfig = null; } if (localLOGV) Slog.v(TAG, "Resuming " + r + " with isForward=" + isForward); WindowManager.LayoutParams l = r.window.getAttributes(); if ((l.softInputMode & WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION) != forwardBit) { l.softInputMode = (l.softInputMode & (~WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION)) | forwardBit; if (r.activity.mVisibleFromClient) { ViewManager wm = a.getWindowManager(); View decor = r.window.getDecorView(); wm.updateViewLayout(decor, l); } } r.activity.mVisibleFromServer = true; mNumVisibleActivities++; if (r.activity.mVisibleFromClient) { r.activity.makeVisible(); } } r.nextIdle = mNewActivities; mNewActivities = r; if (localLOGV) Slog.v(TAG, "Scheduling idle handler for " + r); Looper.myQueue().addIdleHandler(new Idler()); }
这个方法，先去调用onResume()，然后添加View
其中调用onResunme()流程
/** * Resume the activity. * @param token Target activity token. * @param finalStateRequest Flag indicating if this is part of final state resolution for a * transaction. * @param reason Reason for performing the action. * * @return The {@link ActivityClientRecord} that was resumed, {@code null} otherwise. */ @VisibleForTesting public ActivityClientRecord performResumeActivity(IBinder token, boolean finalStateRequest, String reason) { 。。。 try { 。。。 r.activity.performResume(r.startsNotResumed, reason); 。。。 } catch (Exception e) { if (!mInstrumentation.onException(r.activity, e)) { throw new RuntimeException("Unable to resume activity " + r.intent.getComponent().toShortString() + ": " + e.toString(), e); } } return r; }
然后执行activity.performResume()
final void performResume(boolean followedByPause, String reason) { performRestart(true /* start */, reason); mFragments.execPendingActions(); 。。。 // mResumed is set by the instrumentation mInstrumentation.callActivityOnResume(this); writeEventLog(LOG_AM_ON_RESUME_CALLED, reason); 。。。 mFragments.dispatchResume(); mFragments.execPendingActions(); onPostResume(); if (!mCalled) { throw new SuperNotCalledException( "Activity " + mComponent.toShortString() + " did not call through to super.onPostResume()"); } }
也就是通过Instrumentation去调用的onResume()
/** * Perform calling of an activity's {@link Activity#onResume} method. The * default implementation simply calls through to that method. * * @param activity The activity being resumed. */ public void callActivityOnResume(Activity activity) { activity.mResumed = true; activity.onResume(); 。。。。 }
最终执行到了onResume()
/** * Called after {@link #onRestoreInstanceState}, {@link #onRestart}, or * {@link #onPause}, for your activity to start interacting with the user. * This is a good place to begin animations, open exclusive-access devices * (such as the camera), etc. * * <p>Keep in mind that onResume is not the best indicator that your activity * is visible to the user; a system window such as the keyguard may be in * front. Use {@link #onWindowFocusChanged} to know for certain that your * activity is visible to the user (for example, to resume a game). * * <p><em>Derived classes must call through to the super class's * implementation of this method. If they do not, an exception will be * thrown.</em></p> * * @see #onRestoreInstanceState * @see #onRestart * @see #onPostResume * @see #onPause */ @CallSuper protected void onResume() { if (DEBUG_LIFECYCLE) Slog.v(TAG, "onResume " + this); getApplication().dispatchActivityResumed(this); mActivityTransitionState.onResume(this, isTopOfTask()); if (mAutoFillResetNeeded) { if (!mAutoFillIgnoreFirstResumePause) { View focus = getCurrentFocus(); if (focus != null && focus.canNotifyAutofillEnterExitEvent()) { // TODO: in Activity killed/recreated case, i.e. SessionLifecycleTest# // testDatasetVisibleWhileAutofilledAppIsLifecycled: the View's initial // window visibility after recreation is INVISIBLE in onResume() and next frame // ViewRootImpl.performTraversals() changes window visibility to VISIBLE. // So we cannot call View.notifyEnterOrExited() which will do nothing // when View.isVisibleToUser() is false. getAutofillManager().notifyViewEntered(focus); } } } mCalled = true; }
onResume()就完了。。。。
回到handleResumeActivity()方法。。。。
在activity onResume()后，拿到了ActivityClientRecord对象r,通过r取到PhoneWindow，继而取到DecorView，又通过DecorView取到ViewRootImpl对象。
通过activity取到WindowManager,WindowManager是个接口，它继承自ViewManager接口，然后调用viewManager.addView()方法传入DecorView，在这里把DecorView添加进WindowManager。
/** Interface to let you add and remove child views to an Activity. To get an instance * of this class, call {@link android.content.Context#getSystemService(java.lang.String) Context.getSystemService()}. */ public interface ViewManager { /** * Assign the passed LayoutParams to the passed View and add the view to the window. * <p>Throws {@link android.view.WindowManager.BadTokenException} for certain programming * errors, such as adding a second view to a window without removing the first view. * <p>Throws {@link android.view.WindowManager.InvalidDisplayException} if the window is on a * secondary {@link Display} and the specified display can't be found * (see {@link android.app.Presentation}). * @param view The view to be added to this window. * @param params The LayoutParams to assign to view. */ public void addView(View view, ViewGroup.LayoutParams params); public void updateViewLayout(View view, ViewGroup.LayoutParams params); public void removeView(View view); }
实际调用的是WindowManagerImpl.addView()
//绘制3， @Override public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) { applyDefaultToken(params); mGlobal.addView(view, params, mContext.getDisplay(), mParentWindow); }
addView的实现在WindowManagerGlobal里。
//绘制4， public void addView(View view, ViewGroup.LayoutParams params, Display display, Window parentWindow) { if (view == null) { throw new IllegalArgumentException("view must not be null"); } if (display == null) { throw new IllegalArgumentException("display must not be null"); } if (!(params instanceof WindowManager.LayoutParams)) { throw new IllegalArgumentException("Params must be WindowManager.LayoutParams"); } final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params; if (parentWindow != null) { parentWindow.adjustLayoutParamsForSubWindow(wparams); } else { // If there's no parent, then hardware acceleration for this view is // set from the application's hardware acceleration setting. final Context context = view.getContext(); if (context != null && (context.getApplicationInfo().flags & ApplicationInfo.FLAG_HARDWARE_ACCELERATED) != 0) { wparams.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED; } } ViewRootImpl root; View panelParentView = null; synchronized (mLock) { // Start watching for system property changes. if (mSystemPropertyUpdater == null) { mSystemPropertyUpdater = new Runnable() { @Override public void run() { synchronized (mLock) { for (int i = mRoots.size() - 1; i >= 0; --i) { mRoots.get(i).loadSystemProperties(); } } } }; SystemProperties.addChangeCallback(mSystemPropertyUpdater); } int index = findViewLocked(view, false); if (index >= 0) { if (mDyingViews.contains(view)) { // Don't wait for MSG_DIE to make it's way through root's queue. mRoots.get(index).doDie(); } else { throw new IllegalStateException("View " + view + " has already been added to the window manager."); } // The previous removeView() had not completed executing. Now it has. } // If this is a panel window, then find the window it is being // attached to for future reference. if (wparams.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW && wparams.type <= WindowManager.LayoutParams.LAST_SUB_WINDOW) { final int count = mViews.size(); for (int i = 0; i < count; i++) { if (mRoots.get(i).mWindow.asBinder() == wparams.token) { panelParentView = mViews.get(i); } } } root = new ViewRootImpl(view.getContext(), display); //创建ViewRootImpl实例 view.setLayoutParams(wparams); mViews.add(view); mRoots.add(root); mParams.add(wparams); // do this last because it fires off messages to start doing things try { root.setView(view, wparams, panelParentView); //把DecorView加载到Window中 } catch (RuntimeException e) { // BadTokenException or InvalidDisplayException, clean up. if (index >= 0) { removeViewLocked(index, true); } throw e; } } }
在这个方法里，先根据view上下文创建ViewRootImpl，然后给view设置layoutParams，然后setView()
root.setView()方法会调用requestLayout()方法
/** * We have one child */ public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) { synchronized (this) { if (mView == null) { mView = view; mAttachInfo.mDisplayState = mDisplay.getState(); mDisplayManager.registerDisplayListener(mDisplayListener, mHandler); mViewLayoutDirectionInitial = mView.getRawLayoutDirection(); mFallbackEventHandler.setView(view); mWindowAttributes.copyFrom(attrs); if (mWindowAttributes.packageName == null) { mWindowAttributes.packageName = mBasePackageName; } attrs = mWindowAttributes; setTag(); if (DEBUG_KEEP_SCREEN_ON && (mClientWindowLayoutFlags & WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON) != 0 && (attrs.flags&WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON) == 0) { Slog.d(mTag, "setView: FLAG_KEEP_SCREEN_ON changed from true to false!"); } // Keep track of the actual window flags supplied by the client. mClientWindowLayoutFlags = attrs.flags; setAccessibilityFocus(null, null); if (view instanceof RootViewSurfaceTaker) { mSurfaceHolderCallback = ((RootViewSurfaceTaker)view).willYouTakeTheSurface(); if (mSurfaceHolderCallback != null) { mSurfaceHolder = new TakenSurfaceHolder(); mSurfaceHolder.setFormat(PixelFormat.UNKNOWN); mSurfaceHolder.addCallback(mSurfaceHolderCallback); } } // Compute surface insets required to draw at specified Z value. // TODO: Use real shadow insets for a constant max Z. if (!attrs.hasManualSurfaceInsets) { attrs.setSurfaceInsets(view, false /*manual*/, true /*preservePrevious*/); } CompatibilityInfo compatibilityInfo = mDisplay.getDisplayAdjustments().getCompatibilityInfo(); mTranslator = compatibilityInfo.getTranslator(); // If the application owns the surface, don't enable hardware acceleration if (mSurfaceHolder == null) { // While this is supposed to enable only, it can effectively disable // the acceleration too. enableHardwareAcceleration(attrs); final boolean useMTRenderer = MT_RENDERER_AVAILABLE && mAttachInfo.mThreadedRenderer != null; if (mUseMTRenderer != useMTRenderer) { // Shouldn't be resizing, as it's done only in window setup, // but end just in case. endDragResizing(); mUseMTRenderer = useMTRenderer; } } boolean restore = false; if (mTranslator != null) { mSurface.setCompatibilityTranslator(mTranslator); restore = true; attrs.backup(); mTranslator.translateWindowLayout(attrs); } if (DEBUG_LAYOUT) Log.d(mTag, "WindowLayout in setView:" + attrs); if (!compatibilityInfo.supportsScreen()) { attrs.privateFlags |= WindowManager.LayoutParams.PRIVATE_FLAG_COMPATIBLE_WINDOW; mLastInCompatMode = true; } mSoftInputMode = attrs.softInputMode; mWindowAttributesChanged = true; mWindowAttributesChangesFlag = WindowManager.LayoutParams.EVERYTHING_CHANGED; mAttachInfo.mRootView = view; mAttachInfo.mScalingRequired = mTranslator != null; mAttachInfo.mApplicationScale = mTranslator == null ? 1.0f : mTranslator.applicationScale; if (panelParentView != null) { mAttachInfo.mPanelParentWindowToken = panelParentView.getApplicationWindowToken(); } mAdded = true; int res; /* = WindowManagerImpl.ADD_OKAY; */ // Schedule the first layout -before- adding to the window // manager, to make sure we do the relayout before receiving // any other events from the system.在添加到窗口管理器之前安排第一个布局，以确保我们在从系统接收任何其他事件之前进行重新布局。 requestLayout(); if ((mWindowAttributes.inputFeatures & WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHANNEL) == 0) { mInputChannel = new InputChannel(); } mForceDecorViewVisibility = (mWindowAttributes.privateFlags & PRIVATE_FLAG_FORCE_DECOR_VIEW_VISIBILITY) != 0; try { mOrigWindowType = mWindowAttributes.type; mAttachInfo.mRecomputeGlobalAttributes = true; collectViewAttributes(); res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes, getHostVisibility(), mDisplay.getDisplayId(), mWinFrame, mAttachInfo.mContentInsets, mAttachInfo.mStableInsets, mAttachInfo.mOutsets, mAttachInfo.mDisplayCutout, mInputChannel); } catch (RemoteException e) { mAdded = false; mView = null; mAttachInfo.mRootView = null; mInputChannel = null; mFallbackEventHandler.setView(null); unscheduleTraversals(); setAccessibilityFocus(null, null); throw new RuntimeException("Adding window failed", e); } finally { if (restore) { attrs.restore(); } } if (mTranslator != null) { mTranslator.translateRectInScreenToAppWindow(mAttachInfo.mContentInsets); } mPendingOverscanInsets.set(0, 0, 0, 0); mPendingContentInsets.set(mAttachInfo.mContentInsets); mPendingStableInsets.set(mAttachInfo.mStableInsets); mPendingDisplayCutout.set(mAttachInfo.mDisplayCutout); mPendingVisibleInsets.set(0, 0, 0, 0); mAttachInfo.mAlwaysConsumeNavBar = (res & WindowManagerGlobal.ADD_FLAG_ALWAYS_CONSUME_NAV_BAR) != 0; mPendingAlwaysConsumeNavBar = mAttachInfo.mAlwaysConsumeNavBar; if (DEBUG_LAYOUT) Log.v(mTag, "Added window " + mWindow); if (res < WindowManagerGlobal.ADD_OKAY) { mAttachInfo.mRootView = null; mAdded = false; mFallbackEventHandler.setView(null); unscheduleTraversals(); setAccessibilityFocus(null, null); switch (res) { case WindowManagerGlobal.ADD_BAD_APP_TOKEN: case WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN: throw new WindowManager.BadTokenException( "Unable to add window -- token " + attrs.token + " is not valid; is your activity running?"); case WindowManagerGlobal.ADD_NOT_APP_TOKEN: throw new WindowManager.BadTokenException( "Unable to add window -- token " + attrs.token + " is not for an application"); case WindowManagerGlobal.ADD_APP_EXITING: throw new WindowManager.BadTokenException( "Unable to add window -- app for token " + attrs.token + " is exiting"); case WindowManagerGlobal.ADD_DUPLICATE_ADD: throw new WindowManager.BadTokenException( "Unable to add window -- window " + mWindow + " has already been added"); case WindowManagerGlobal.ADD_STARTING_NOT_NEEDED: // Silently ignore -- we would have just removed it // right away, anyway. return; case WindowManagerGlobal.ADD_MULTIPLE_SINGLETON: throw new WindowManager.BadTokenException("Unable to add window " + mWindow + " -- another window of type " + mWindowAttributes.type + " already exists"); case WindowManagerGlobal.ADD_PERMISSION_DENIED: throw new WindowManager.BadTokenException("Unable to add window " + mWindow + " -- permission denied for window type " + mWindowAttributes.type); case WindowManagerGlobal.ADD_INVALID_DISPLAY: throw new WindowManager.InvalidDisplayException("Unable to add window " + mWindow + " -- the specified display can not be found"); case WindowManagerGlobal.ADD_INVALID_TYPE: throw new WindowManager.InvalidDisplayException("Unable to add window " + mWindow + " -- the specified window type " + mWindowAttributes.type + " is not valid"); } throw new RuntimeException( "Unable to add window -- unknown error code " + res); } if (view instanceof RootViewSurfaceTaker) { mInputQueueCallback = ((RootViewSurfaceTaker)view).willYouTakeTheInputQueue(); } if (mInputChannel != null) { if (mInputQueueCallback != null) { mInputQueue = new InputQueue(); mInputQueueCallback.onInputQueueCreated(mInputQueue); } mInputEventReceiver = new WindowInputEventReceiver(mInputChannel, Looper.myLooper()); } view.assignParent(this); mAddedTouchMode = (res & WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE) != 0; mAppVisible = (res & WindowManagerGlobal.ADD_FLAG_APP_VISIBLE) != 0; if (mAccessibilityManager.isEnabled()) { mAccessibilityInteractionConnectionManager.ensureConnection(); } if (view.getImportantForAccessibility() == View.IMPORTANT_FOR_ACCESSIBILITY_AUTO) { view.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES); } // Set up the input pipeline. CharSequence counterSuffix = attrs.getTitle(); mSyntheticInputStage = new SyntheticInputStage(); InputStage viewPostImeStage = new ViewPostImeInputStage(mSyntheticInputStage); InputStage nativePostImeStage = new NativePostImeInputStage(viewPostImeStage, "aq:native-post-ime:" + counterSuffix); InputStage earlyPostImeStage = new EarlyPostImeInputStage(nativePostImeStage); InputStage imeStage = new ImeInputStage(earlyPostImeStage, "aq:ime:" + counterSuffix); InputStage viewPreImeStage = new ViewPreImeInputStage(imeStage); InputStage nativePreImeStage = new NativePreImeInputStage(viewPreImeStage, "aq:native-pre-ime:" + counterSuffix); mFirstInputStage = nativePreImeStage; mFirstPostImeInputStage = earlyPostImeStage; mPendingInputEventQueueLengthCounterName = "aq:pending:" + counterSuffix; } } }
requestLayout()会调用scheduleTraversals()方法加入计划任务
@Override public void requestLayout() { if (!mHandlingLayoutInLayoutRequest) { checkThread(); mLayoutRequested = true; scheduleTraversals(); } }
实际调用
void scheduleTraversals() { if (!mTraversalScheduled) { mTraversalScheduled = true; mTraversalBarrier = mHandler.getLooper().getQueue().postSyncBarrier(); mChoreographer.postCallback( Choreographer.CALLBACK_TRAVERSAL, mTraversalRunnable, null); if (!mUnbufferedInputDispatch) { scheduleConsumeBatchedInput(); } notifyRendererOfFramePending(); pokeDrawLockIfNeeded(); } }
绘制View消息入队方法
在handleResumeActivity()执行完成后，会给当前Looper MessageQueue添加一个IdleHandler()。。。。
ViewRootImpl在线程内，处理收到的view绘制信息
final class TraversalRunnable implements Runnable { @Override public void run() { doTraversal(); } } //绘制V5，直接new线程了 final TraversalRunnable mTraversalRunnable = new TraversalRunnable();
//绘制V6，线程里执行 void doTraversal() { if (mTraversalScheduled) { mTraversalScheduled = false; mHandler.getLooper().getQueue().removeSyncBarrier(mTraversalBarrier); if (mProfile) { Debug.startMethodTracing("ViewAncestor"); } performTraversals(); //划重点 if (mProfile) { Debug.stopMethodTracing(); mProfile = false; } } }
方法调用了view绘制的执行方法，performTraversals().
Traversal 遍历 英[træ'vɜ:sl]
ViewRootImpl.performTraversals()
//绘制V7，自定义View的三个步骤都在这里面了 private void performTraversals() { // cache mView since it is used so much below... final View host = mView; if (DBG) { System.out.println("======================================"); System.out.println("performTraversals"); host.debug(); } if (host == null || !mAdded) return; mIsInTraversal = true; mWillDrawSoon = true; boolean windowSizeMayChange = false; boolean newSurface = false; boolean surfaceChanged = false; WindowManager.LayoutParams lp = mWindowAttributes; int desiredWindowWidth; int desiredWindowHeight; final int viewVisibility = getHostVisibility(); final boolean viewVisibilityChanged = !mFirst && (mViewVisibility != viewVisibility || mNewSurfaceNeeded // Also check for possible double visibility update, which will make current // viewVisibility value equal to mViewVisibility and we may miss it. || mAppVisibilityChanged); mAppVisibilityChanged = false; final boolean viewUserVisibilityChanged = !mFirst && ((mViewVisibility == View.VISIBLE) != (viewVisibility == View.VISIBLE)); WindowManager.LayoutParams params = null; if (mWindowAttributesChanged) { mWindowAttributesChanged = false; surfaceChanged = true; params = lp; } CompatibilityInfo compatibilityInfo = mDisplay.getDisplayAdjustments().getCompatibilityInfo(); if (compatibilityInfo.supportsScreen() == mLastInCompatMode) { params = lp; mFullRedrawNeeded = true; mLayoutRequested = true; if (mLastInCompatMode) { params.privateFlags &= ~WindowManager.LayoutParams.PRIVATE_FLAG_COMPATIBLE_WINDOW; mLastInCompatMode = false; } else { params.privateFlags |= WindowManager.LayoutParams.PRIVATE_FLAG_COMPATIBLE_WINDOW; mLastInCompatMode = true; } } mWindowAttributesChangesFlag = 0; Rect frame = mWinFrame; if (mFirst) { mFullRedrawNeeded = true; mLayoutRequested = true; final Configuration config = mContext.getResources().getConfiguration(); if (shouldUseDisplaySize(lp)) { // NOTE -- system code, won't try to do compat mode. Point size = new Point(); mDisplay.getRealSize(size); desiredWindowWidth = size.x; desiredWindowHeight = size.y; } else { desiredWindowWidth = mWinFrame.width(); desiredWindowHeight = mWinFrame.height(); } // We used to use the following condition to choose 32 bits drawing caches: // PixelFormat.hasAlpha(lp.format) || lp.format == PixelFormat.RGBX_8888 // However, windows are now always 32 bits by default, so choose 32 bits mAttachInfo.mUse32BitDrawingCache = true; mAttachInfo.mHasWindowFocus = false; mAttachInfo.mWindowVisibility = viewVisibility; mAttachInfo.mRecomputeGlobalAttributes = false; mLastConfigurationFromResources.setTo(config); mLastSystemUiVisibility = mAttachInfo.mSystemUiVisibility; // Set the layout direction if it has not been set before (inherit is the default) if (mViewLayoutDirectionInitial == View.LAYOUT_DIRECTION_INHERIT) { host.setLayoutDirection(config.getLayoutDirection()); } host.dispatchAttachedToWindow(mAttachInfo, 0); mAttachInfo.mTreeObserver.dispatchOnWindowAttachedChange(true); dispatchApplyInsets(host); } else { desiredWindowWidth = frame.width(); desiredWindowHeight = frame.height(); if (desiredWindowWidth != mWidth || desiredWindowHeight != mHeight) { if (DEBUG_ORIENTATION) Log.v(mTag, "View " + host + " resized to: " + frame); mFullRedrawNeeded = true; mLayoutRequested = true; windowSizeMayChange = true; } } if (viewVisibilityChanged) { mAttachInfo.mWindowVisibility = viewVisibility; host.dispatchWindowVisibilityChanged(viewVisibility); if (viewUserVisibilityChanged) { host.dispatchVisibilityAggregated(viewVisibility == View.VISIBLE); } if (viewVisibility != View.VISIBLE || mNewSurfaceNeeded) { endDragResizing(); destroyHardwareResources(); } if (viewVisibility == View.GONE) { // After making a window gone, we will count it as being // shown for the first time the next time it gets focus. mHasHadWindowFocus = false; } } // Non-visible windows can't hold accessibility focus. if (mAttachInfo.mWindowVisibility != View.VISIBLE) { host.clearAccessibilityFocus(); } // Execute enqueued actions on every traversal in case a detached view enqueued an action getRunQueue().executeActions(mAttachInfo.mHandler); boolean insetsChanged = false; boolean layoutRequested = mLayoutRequested && (!mStopped || mReportNextDraw); if (layoutRequested) { final Resources res = mView.getContext().getResources(); if (mFirst) { // make sure touch mode code executes by setting cached value // to opposite of the added touch mode. mAttachInfo.mInTouchMode = !mAddedTouchMode; ensureTouchModeLocally(mAddedTouchMode); } else { if (!mPendingOverscanInsets.equals(mAttachInfo.mOverscanInsets)) { insetsChanged = true; } if (!mPendingContentInsets.equals(mAttachInfo.mContentInsets)) { insetsChanged = true; } if (!mPendingStableInsets.equals(mAttachInfo.mStableInsets)) { insetsChanged = true; } if (!mPendingDisplayCutout.equals(mAttachInfo.mDisplayCutout)) { insetsChanged = true; } if (!mPendingVisibleInsets.equals(mAttachInfo.mVisibleInsets)) { mAttachInfo.mVisibleInsets.set(mPendingVisibleInsets); if (DEBUG_LAYOUT) Log.v(mTag, "Visible insets changing to: " + mAttachInfo.mVisibleInsets); } if (!mPendingOutsets.equals(mAttachInfo.mOutsets)) { insetsChanged = true; } if (mPendingAlwaysConsumeNavBar != mAttachInfo.mAlwaysConsumeNavBar) { insetsChanged = true; } if (lp.width == ViewGroup.LayoutParams.WRAP_CONTENT || lp.height == ViewGroup.LayoutParams.WRAP_CONTENT) { windowSizeMayChange = true; if (shouldUseDisplaySize(lp)) { // NOTE -- system code, won't try to do compat mode. Point size = new Point(); mDisplay.getRealSize(size); desiredWindowWidth = size.x; desiredWindowHeight = size.y; } else { Configuration config = res.getConfiguration(); desiredWindowWidth = dipToPx(config.screenWidthDp); desiredWindowHeight = dipToPx(config.screenHeightDp); } } } // Ask host how big it wants to be windowSizeMayChange |= measureHierarchy(host, lp, res, desiredWindowWidth, desiredWindowHeight); } if (collectViewAttributes()) { params = lp; } if (mAttachInfo.mForceReportNewAttributes) { mAttachInfo.mForceReportNewAttributes = false; params = lp; } if (mFirst || mAttachInfo.mViewVisibilityChanged) { mAttachInfo.mViewVisibilityChanged = false; int resizeMode = mSoftInputMode & WindowManager.LayoutParams.SOFT_INPUT_MASK_ADJUST; // If we are in auto resize mode, then we need to determine // what mode to use now. if (resizeMode == WindowManager.LayoutParams.SOFT_INPUT_ADJUST_UNSPECIFIED) { final int N = mAttachInfo.mScrollContainers.size(); for (int i=0; i<N; i++) { if (mAttachInfo.mScrollContainers.get(i).isShown()) { resizeMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE; } } if (resizeMode == 0) { resizeMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN; } if ((lp.softInputMode & WindowManager.LayoutParams.SOFT_INPUT_MASK_ADJUST) != resizeMode) { lp.softInputMode = (lp.softInputMode & ~WindowManager.LayoutParams.SOFT_INPUT_MASK_ADJUST) | resizeMode; params = lp; } } } if (params != null) { if ((host.mPrivateFlags & View.PFLAG_REQUEST_TRANSPARENT_REGIONS) != 0) { if (!PixelFormat.formatHasAlpha(params.format)) { params.format = PixelFormat.TRANSLUCENT; } } mAttachInfo.mOverscanRequested = (params.flags & WindowManager.LayoutParams.FLAG_LAYOUT_IN_OVERSCAN) != 0; } if (mApplyInsetsRequested) { mApplyInsetsRequested = false; mLastOverscanRequested = mAttachInfo.mOverscanRequested; dispatchApplyInsets(host); if (mLayoutRequested) { // Short-circuit catching a new layout request here, so // we don't need to go through two layout passes when things // change due to fitting system windows, which can happen a lot. windowSizeMayChange |= measureHierarchy(host, lp, mView.getContext().getResources(), desiredWindowWidth, desiredWindowHeight); } } if (layoutRequested) { // Clear this now, so that if anything requests a layout in the // rest of this function we will catch it and re-run a full // layout pass. mLayoutRequested = false; } boolean windowShouldResize = layoutRequested && windowSizeMayChange && ((mWidth != host.getMeasuredWidth() || mHeight != host.getMeasuredHeight()) || (lp.width == ViewGroup.LayoutParams.WRAP_CONTENT && frame.width() < desiredWindowWidth && frame.width() != mWidth) || (lp.height == ViewGroup.LayoutParams.WRAP_CONTENT && frame.height() < desiredWindowHeight && frame.height() != mHeight)); windowShouldResize |= mDragResizing && mResizeMode == RESIZE_MODE_FREEFORM; // If the activity was just relaunched, it might have unfrozen the task bounds (while // relaunching), so we need to force a call into window manager to pick up the latest // bounds. windowShouldResize |= mActivityRelaunched; // Determine whether to compute insets. // If there are no inset listeners remaining then we may still need to compute // insets in case the old insets were non-empty and must be reset. final boolean computesInternalInsets = mAttachInfo.mTreeObserver.hasComputeInternalInsetsListeners() || mAttachInfo.mHasNonEmptyGivenInternalInsets; boolean insetsPending = false; int relayoutResult = 0; boolean updatedConfiguration = false; final int surfaceGenerationId = mSurface.getGenerationId(); final boolean isViewVisible = viewVisibility == View.VISIBLE; final boolean windowRelayoutWasForced = mForceNextWindowRelayout; if (mFirst || windowShouldResize || insetsChanged || viewVisibilityChanged || params != null || mForceNextWindowRelayout) { mForceNextWindowRelayout = false; if (isViewVisible) { // If this window is giving internal insets to the window // manager, and it is being added or changing its visibility, // then we want to first give the window manager "fake" // insets to cause it to effectively ignore the content of // the window during layout. This avoids it briefly causing // other windows to resize/move based on the raw frame of the // window, waiting until we can finish laying out this window // and get back to the window manager with the ultimately // computed insets. insetsPending = computesInternalInsets && (mFirst || viewVisibilityChanged); } if (mSurfaceHolder != null) { mSurfaceHolder.mSurfaceLock.lock(); mDrawingAllowed = true; } boolean hwInitialized = false; boolean contentInsetsChanged = false; boolean hadSurface = mSurface.isValid(); try { if (DEBUG_LAYOUT) { Log.i(mTag, "host=w:" + host.getMeasuredWidth() + ", h:" + host.getMeasuredHeight() + ", params=" + params); } if (mAttachInfo.mThreadedRenderer != null) { // relayoutWindow may decide to destroy mSurface. As that decision // happens in WindowManager service, we need to be defensive here // and stop using the surface in case it gets destroyed. if (mAttachInfo.mThreadedRenderer.pauseSurface(mSurface)) { // Animations were running so we need to push a frame // to resume them mDirty.set(0, 0, mWidth, mHeight); } mChoreographer.mFrameInfo.addFlags(FrameInfo.FLAG_WINDOW_LAYOUT_CHANGED); } relayoutResult = relayoutWindow(params, viewVisibility, insetsPending); if (DEBUG_LAYOUT) Log.v(mTag, "relayout: frame=" + frame.toShortString() + " overscan=" + mPendingOverscanInsets.toShortString() + " content=" + mPendingContentInsets.toShortString() + " visible=" + mPendingVisibleInsets.toShortString() + " stable=" + mPendingStableInsets.toShortString() + " cutout=" + mPendingDisplayCutout.get().toString() + " outsets=" + mPendingOutsets.toShortString() + " surface=" + mSurface); // If the pending {@link MergedConfiguration} handed back from // {@link #relayoutWindow} does not match the one last reported, // WindowManagerService has reported back a frame from a configuration not yet // handled by the client. In this case, we need to accept the configuration so we // do not lay out and draw with the wrong configuration. if (!mPendingMergedConfiguration.equals(mLastReportedMergedConfiguration)) { if (DEBUG_CONFIGURATION) Log.v(mTag, "Visible with new config: " + mPendingMergedConfiguration.getMergedConfiguration()); performConfigurationChange(mPendingMergedConfiguration, !mFirst, INVALID_DISPLAY /* same display */); updatedConfiguration = true; } final boolean overscanInsetsChanged = !mPendingOverscanInsets.equals( mAttachInfo.mOverscanInsets); contentInsetsChanged = !mPendingContentInsets.equals( mAttachInfo.mContentInsets); final boolean visibleInsetsChanged = !mPendingVisibleInsets.equals( mAttachInfo.mVisibleInsets); final boolean stableInsetsChanged = !mPendingStableInsets.equals( mAttachInfo.mStableInsets); final boolean cutoutChanged = !mPendingDisplayCutout.equals( mAttachInfo.mDisplayCutout); final boolean outsetsChanged = !mPendingOutsets.equals(mAttachInfo.mOutsets); final boolean surfaceSizeChanged = (relayoutResult & WindowManagerGlobal.RELAYOUT_RES_SURFACE_RESIZED) != 0; surfaceChanged |= surfaceSizeChanged; final boolean alwaysConsumeNavBarChanged = mPendingAlwaysConsumeNavBar != mAttachInfo.mAlwaysConsumeNavBar; if (contentInsetsChanged) { mAttachInfo.mContentInsets.set(mPendingContentInsets); if (DEBUG_LAYOUT) Log.v(mTag, "Content insets changing to: " + mAttachInfo.mContentInsets); } if (overscanInsetsChanged) { mAttachInfo.mOverscanInsets.set(mPendingOverscanInsets); if (DEBUG_LAYOUT) Log.v(mTag, "Overscan insets changing to: " + mAttachInfo.mOverscanInsets); // Need to relayout with content insets. contentInsetsChanged = true; } if (stableInsetsChanged) { mAttachInfo.mStableInsets.set(mPendingStableInsets); if (DEBUG_LAYOUT) Log.v(mTag, "Decor insets changing to: " + mAttachInfo.mStableInsets); // Need to relayout with content insets. contentInsetsChanged = true; } if (cutoutChanged) { mAttachInfo.mDisplayCutout.set(mPendingDisplayCutout); if (DEBUG_LAYOUT) { Log.v(mTag, "DisplayCutout changing to: " + mAttachInfo.mDisplayCutout); } // Need to relayout with content insets. contentInsetsChanged = true; } if (alwaysConsumeNavBarChanged) { mAttachInfo.mAlwaysConsumeNavBar = mPendingAlwaysConsumeNavBar; contentInsetsChanged = true; } if (contentInsetsChanged || mLastSystemUiVisibility != mAttachInfo.mSystemUiVisibility || mApplyInsetsRequested || mLastOverscanRequested != mAttachInfo.mOverscanRequested || outsetsChanged) { mLastSystemUiVisibility = mAttachInfo.mSystemUiVisibility; mLastOverscanRequested = mAttachInfo.mOverscanRequested; mAttachInfo.mOutsets.set(mPendingOutsets); mApplyInsetsRequested = false; dispatchApplyInsets(host); } if (visibleInsetsChanged) { mAttachInfo.mVisibleInsets.set(mPendingVisibleInsets); if (DEBUG_LAYOUT) Log.v(mTag, "Visible insets changing to: " + mAttachInfo.mVisibleInsets); } if (!hadSurface) { if (mSurface.isValid()) { // If we are creating a new surface, then we need to // completely redraw it. Also, when we get to the // point of drawing it we will hold off and schedule // a new traversal instead. This is so we can tell the // window manager about all of the windows being displayed // before actually drawing them, so it can display then // all at once. newSurface = true; mFullRedrawNeeded = true; mPreviousTransparentRegion.setEmpty(); // Only initialize up-front if transparent regions are not // requested, otherwise defer to see if the entire window // will be transparent if (mAttachInfo.mThreadedRenderer != null) { try { hwInitialized = mAttachInfo.mThreadedRenderer.initialize( mSurface); if (hwInitialized && (host.mPrivateFlags & View.PFLAG_REQUEST_TRANSPARENT_REGIONS) == 0) { // Don't pre-allocate if transparent regions // are requested as they may not be needed mSurface.allocateBuffers(); } } catch (OutOfResourcesException e) { handleOutOfResourcesException(e); return; } } } } else if (!mSurface.isValid()) { // If the surface has been removed, then reset the scroll // positions. if (mLastScrolledFocus != null) { mLastScrolledFocus.clear(); } mScrollY = mCurScrollY = 0; if (mView instanceof RootViewSurfaceTaker) { ((RootViewSurfaceTaker) mView).onRootViewScrollYChanged(mCurScrollY); } if (mScroller != null) { mScroller.abortAnimation(); } // Our surface is gone if (mAttachInfo.mThreadedRenderer != null && mAttachInfo.mThreadedRenderer.isEnabled()) { mAttachInfo.mThreadedRenderer.destroy(); } } else if ((surfaceGenerationId != mSurface.getGenerationId() || surfaceSizeChanged || windowRelayoutWasForced) && mSurfaceHolder == null && mAttachInfo.mThreadedRenderer != null) { mFullRedrawNeeded = true; try { // Need to do updateSurface (which leads to CanvasContext::setSurface and // re-create the EGLSurface) if either the Surface changed (as indicated by // generation id), or WindowManager changed the surface size. The latter is // because on some chips, changing the consumer side's BufferQueue size may // not take effect immediately unless we create a new EGLSurface. // Note that frame size change doesn't always imply surface size change (eg. // drag resizing uses fullscreen surface), need to check surfaceSizeChanged // flag from WindowManager. mAttachInfo.mThreadedRenderer.updateSurface(mSurface); } catch (OutOfResourcesException e) { handleOutOfResourcesException(e); return; } } final boolean freeformResizing = (relayoutResult & WindowManagerGlobal.RELAYOUT_RES_DRAG_RESIZING_FREEFORM) != 0; final boolean dockedResizing = (relayoutResult & WindowManagerGlobal.RELAYOUT_RES_DRAG_RESIZING_DOCKED) != 0; final boolean dragResizing = freeformResizing || dockedResizing; if (mDragResizing != dragResizing) { if (dragResizing) { mResizeMode = freeformResizing ? RESIZE_MODE_FREEFORM : RESIZE_MODE_DOCKED_DIVIDER; // TODO: Need cutout? startDragResizing(mPendingBackDropFrame, mWinFrame.equals(mPendingBackDropFrame), mPendingVisibleInsets, mPendingStableInsets, mResizeMode); } else { // We shouldn't come here, but if we come we should end the resize. endDragResizing(); } } if (!mUseMTRenderer) { if (dragResizing) { mCanvasOffsetX = mWinFrame.left; mCanvasOffsetY = mWinFrame.top; } else { mCanvasOffsetX = mCanvasOffsetY = 0; } } } catch (RemoteException e) { } if (DEBUG_ORIENTATION) Log.v( TAG, "Relayout returned: frame=" + frame + ", surface=" + mSurface); mAttachInfo.mWindowLeft = frame.left; mAttachInfo.mWindowTop = frame.top; // !!FIXME!! This next section handles the case where we did not get the // window size we asked for. We should avoid this by getting a maximum size from // the window session beforehand. if (mWidth != frame.width() || mHeight != frame.height()) { mWidth = frame.width(); mHeight = frame.height(); } if (mSurfaceHolder != null) { // The app owns the surface; tell it about what is going on. if (mSurface.isValid()) { // XXX .copyFrom() doesn't work! //mSurfaceHolder.mSurface.copyFrom(mSurface); mSurfaceHolder.mSurface = mSurface; } mSurfaceHolder.setSurfaceFrameSize(mWidth, mHeight); mSurfaceHolder.mSurfaceLock.unlock(); if (mSurface.isValid()) { if (!hadSurface) { mSurfaceHolder.ungetCallbacks(); mIsCreating = true; SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks(); if (callbacks != null) { for (SurfaceHolder.Callback c : callbacks) { c.surfaceCreated(mSurfaceHolder); } } surfaceChanged = true; } if (surfaceChanged || surfaceGenerationId != mSurface.getGenerationId()) { SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks(); if (callbacks != null) { for (SurfaceHolder.Callback c : callbacks) { c.surfaceChanged(mSurfaceHolder, lp.format, mWidth, mHeight); } } } mIsCreating = false; } else if (hadSurface) { mSurfaceHolder.ungetCallbacks(); SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks(); if (callbacks != null) { for (SurfaceHolder.Callback c : callbacks) { c.surfaceDestroyed(mSurfaceHolder); } } mSurfaceHolder.mSurfaceLock.lock(); try { mSurfaceHolder.mSurface = new Surface(); } finally { mSurfaceHolder.mSurfaceLock.unlock(); } } } final ThreadedRenderer threadedRenderer = mAttachInfo.mThreadedRenderer; if (threadedRenderer != null && threadedRenderer.isEnabled()) { if (hwInitialized || mWidth != threadedRenderer.getWidth() || mHeight != threadedRenderer.getHeight() || mNeedsRendererSetup) { threadedRenderer.setup(mWidth, mHeight, mAttachInfo, mWindowAttributes.surfaceInsets); mNeedsRendererSetup = false; } } if (!mStopped || mReportNextDraw) { boolean focusChangedDueToTouchMode = ensureTouchModeLocally( (relayoutResult&WindowManagerGlobal.RELAYOUT_RES_IN_TOUCH_MODE) != 0); if (focusChangedDueToTouchMode || mWidth != host.getMeasuredWidth() || mHeight != host.getMeasuredHeight() || contentInsetsChanged || updatedConfiguration) { int childWidthMeasureSpec = getRootMeasureSpec(mWidth, lp.width); int childHeightMeasureSpec = getRootMeasureSpec(mHeight, lp.height); if (DEBUG_LAYOUT) Log.v(mTag, "Ooops, something changed! mWidth=" + mWidth + " measuredWidth=" + host.getMeasuredWidth() + " mHeight=" + mHeight + " measuredHeight=" + host.getMeasuredHeight() + " coveredInsetsChanged=" + contentInsetsChanged); // Ask host how big it wants to be测量，想要多大 performMeasure(childWidthMeasureSpec, childHeightMeasureSpec); //绘制V8 // Implementation of weights from WindowManager.LayoutParams // We just grow the dimensions as needed and re-measure if // needs be int width = host.getMeasuredWidth(); int height = host.getMeasuredHeight(); boolean measureAgain = false; if (lp.horizontalWeight > 0.0f) { width += (int) ((mWidth - width) * lp.horizontalWeight); childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY); measureAgain = true; } if (lp.verticalWeight > 0.0f) { height += (int) ((mHeight - height) * lp.verticalWeight); childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY); measureAgain = true; } if (measureAgain) { if (DEBUG_LAYOUT) Log.v(mTag, "And hey let's measure once more: width=" + width + " height=" + height); performMeasure(childWidthMeasureSpec, childHeightMeasureSpec); } layoutRequested = true; } } } else { // Not the first pass and no window/insets/visibility change but the window // may have moved and we need check that and if so to update the left and right // in the attach info. We translate only the window frame since on window move // the window manager tells us only for the new frame but the insets are the // same and we do not want to translate them more than once. maybeHandleWindowMove(frame); } final boolean didLayout = layoutRequested && (!mStopped || mReportNextDraw); boolean triggerGlobalLayoutListener = didLayout || mAttachInfo.mRecomputeGlobalAttributes; if (didLayout) { performLayout(lp, mWidth, mHeight);//布局 // By this point all views have been sized and positioned // We can compute the transparent area if ((host.mPrivateFlags & View.PFLAG_REQUEST_TRANSPARENT_REGIONS) != 0) { // start out transparent // TODO: AVOID THAT CALL BY CACHING THE RESULT? host.getLocationInWindow(mTmpLocation); mTransparentRegion.set(mTmpLocation[0], mTmpLocation[1], mTmpLocation[0] + host.mRight - host.mLeft, mTmpLocation[1] + host.mBottom - host.mTop); host.gatherTransparentRegion(mTransparentRegion); if (mTranslator != null) { mTranslator.translateRegionInWindowToScreen(mTransparentRegion); } if (!mTransparentRegion.equals(mPreviousTransparentRegion)) { mPreviousTransparentRegion.set(mTransparentRegion); mFullRedrawNeeded = true; // reconfigure window manager try { mWindowSession.setTransparentRegion(mWindow, mTransparentRegion); } catch (RemoteException e) { } } } if (DBG) { System.out.println("======================================"); System.out.println("performTraversals -- after setFrame"); host.debug(); } } if (triggerGlobalLayoutListener) { mAttachInfo.mRecomputeGlobalAttributes = false; mAttachInfo.mTreeObserver.dispatchOnGlobalLayout(); } if (computesInternalInsets) { // Clear the original insets. final ViewTreeObserver.InternalInsetsInfo insets = mAttachInfo.mGivenInternalInsets; insets.reset(); // Compute new insets in place. mAttachInfo.mTreeObserver.dispatchOnComputeInternalInsets(insets); mAttachInfo.mHasNonEmptyGivenInternalInsets = !insets.isEmpty(); // Tell the window manager. if (insetsPending || !mLastGivenInsets.equals(insets)) { mLastGivenInsets.set(insets); // Translate insets to screen coordinates if needed. final Rect contentInsets; final Rect visibleInsets; final Region touchableRegion; if (mTranslator != null) { contentInsets = mTranslator.getTranslatedContentInsets(insets.contentInsets); visibleInsets = mTranslator.getTranslatedVisibleInsets(insets.visibleInsets); touchableRegion = mTranslator.getTranslatedTouchableArea(insets.touchableRegion); } else { contentInsets = insets.contentInsets; visibleInsets = insets.visibleInsets; touchableRegion = insets.touchableRegion; } try { mWindowSession.setInsets(mWindow, insets.mTouchableInsets, contentInsets, visibleInsets, touchableRegion); } catch (RemoteException e) { } } } if (mFirst) { if (sAlwaysAssignFocus || !isInTouchMode()) { // handle first focus request if (DEBUG_INPUT_RESIZE) { Log.v(mTag, "First: mView.hasFocus()=" + mView.hasFocus()); } if (mView != null) { if (!mView.hasFocus()) { mView.restoreDefaultFocus(); if (DEBUG_INPUT_RESIZE) { Log.v(mTag, "First: requested focused view=" + mView.findFocus()); } } else { if (DEBUG_INPUT_RESIZE) { Log.v(mTag, "First: existing focused view=" + mView.findFocus()); } } } } else { // Some views (like ScrollView) won't hand focus to descendants that aren't within // their viewport. Before layout, there's a good change these views are size 0 // which means no children can get focus. After layout, this view now has size, but // is not guaranteed to hand-off focus to a focusable child (specifically, the edge- // case where the child has a size prior to layout and thus won't trigger // focusableViewAvailable). View focused = mView.findFocus(); if (focused instanceof ViewGroup && ((ViewGroup) focused).getDescendantFocusability() == ViewGroup.FOCUS_AFTER_DESCENDANTS) { focused.restoreDefaultFocus(); } } } final boolean changedVisibility = (viewVisibilityChanged || mFirst) && isViewVisible; final boolean hasWindowFocus = mAttachInfo.mHasWindowFocus && isViewVisible; final boolean regainedFocus = hasWindowFocus && mLostWindowFocus; if (regainedFocus) { mLostWindowFocus = false; } else if (!hasWindowFocus && mHadWindowFocus) { mLostWindowFocus = true; } if (changedVisibility || regainedFocus) { // Toasts are presented as notifications - don't present them as windows as well boolean isToast = (mWindowAttributes == null) ? false : (mWindowAttributes.type == WindowManager.LayoutParams.TYPE_TOAST); if (!isToast) { host.sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED); } } mFirst = false; mWillDrawSoon = false; mNewSurfaceNeeded = false; mActivityRelaunched = false; mViewVisibility = viewVisibility; mHadWindowFocus = hasWindowFocus; if (hasWindowFocus && !isInLocalFocusMode()) { final boolean imTarget = WindowManager.LayoutParams .mayUseInputMethod(mWindowAttributes.flags); if (imTarget != mLastWasImTarget) { mLastWasImTarget = imTarget; InputMethodManager imm = InputMethodManager.peekInstance(); if (imm != null && imTarget) { imm.onPreWindowFocus(mView, hasWindowFocus); imm.onPostWindowFocus(mView, mView.findFocus(), mWindowAttributes.softInputMode, !mHasHadWindowFocus, mWindowAttributes.flags); } } } // Remember if we must report the next draw. if ((relayoutResult & WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) { reportNextDraw(); } boolean cancelDraw = mAttachInfo.mTreeObserver.dispatchOnPreDraw() || !isViewVisible; if (!cancelDraw && !newSurface) { if (mPendingTransitions != null && mPendingTransitions.size() > 0) { for (int i = 0; i < mPendingTransitions.size(); ++i) { mPendingTransitions.get(i).startChangingAnimations(); } mPendingTransitions.clear(); } performDraw(); //绘制 } else { if (isViewVisible) { // Try again scheduleTraversals(); } else if (mPendingTransitions != null && mPendingTransitions.size() > 0) { for (int i = 0; i < mPendingTransitions.size(); ++i) { mPendingTransitions.get(i).endChangingAnimations(); } mPendingTransitions.clear(); } } mIsInTraversal = false; }
相当庞大，里面依次执行view绘制三步
测量
// Ask host how big it wants to be测量，想要多大 performMeasure(childWidthMeasureSpec, childHeightMeasureSpec); //绘制V8
摆放
performLayout(lp, mWidth, mHeight);//布局
绘制
performDraw(); //绘制
第一步，测量
//绘制V8，测量 private void performMeasure(int childWidthMeasureSpec, int childHeightMeasureSpec) { if (mView == null) { return; } Trace.traceBegin(Trace.TRACE_TAG_VIEW, "measure"); try { mView.measure(childWidthMeasureSpec, childHeightMeasureSpec); //View的自测量 } finally { Trace.traceEnd(Trace.TRACE_TAG_VIEW); } }
调用View.measure（）
/** 绘制V9，视图测量自己 * <p> * This is called to find out how big a view should be. The parent调用它来查明视图应该有多大。 父母 * supplies constraint information in the width and height parameters.提供宽度和高度参数中的约束信息。 * </p> * * <p> * The actual measurement work of a view is performed in * {@link #onMeasure(int, int)}, called by this method. Therefore, only * {@link #onMeasure(int, int)} can and must be overridden by subclasses. * </p> * * * @param widthMeasureSpec Horizontal space requirements as imposed by the * parent * @param heightMeasureSpec Vertical space requirements as imposed by the * parent * * @see #onMeasure(int, int) */ public final void measure(int widthMeasureSpec, int heightMeasureSpec) { boolean optical = isLayoutModeOptical(this); if (optical != isLayoutModeOptical(mParent)) { Insets insets = getOpticalInsets(); int oWidth = insets.left + insets.right; int oHeight = insets.top + insets.bottom; widthMeasureSpec = MeasureSpec.adjust(widthMeasureSpec, optical ? -oWidth : oWidth); heightMeasureSpec = MeasureSpec.adjust(heightMeasureSpec, optical ? -oHeight : oHeight); } // Suppress sign extension for the low bytes long key = (long) widthMeasureSpec << 32 | (long) heightMeasureSpec & 0xffffffffL; if (mMeasureCache == null) mMeasureCache = new LongSparseLongArray(2); final boolean forceLayout = (mPrivateFlags & PFLAG_FORCE_LAYOUT) == PFLAG_FORCE_LAYOUT; // Optimize layout by avoiding an extra EXACTLY pass when the view is // already measured as the correct size. In API 23 and below, this // extra pass is required to make LinearLayout re-distribute weight. final boolean specChanged = widthMeasureSpec != mOldWidthMeasureSpec || heightMeasureSpec != mOldHeightMeasureSpec; final boolean isSpecExactly = MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY && MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.EXACTLY; final boolean matchesSpecSize = getMeasuredWidth() == MeasureSpec.getSize(widthMeasureSpec) && getMeasuredHeight() == MeasureSpec.getSize(heightMeasureSpec); final boolean needsLayout = specChanged && (sAlwaysRemeasureExactly || !isSpecExactly || !matchesSpecSize); if (forceLayout || needsLayout) { // first clears the measured dimension flag mPrivateFlags &= ~PFLAG_MEASURED_DIMENSION_SET; resolveRtlPropertiesIfNeeded(); int cacheIndex = forceLayout ? -1 : mMeasureCache.indexOfKey(key); if (cacheIndex < 0 || sIgnoreMeasureCache) { // measure ourselves, this should set the measured dimension flag back测量自己，这应该设置测量尺寸标志 onMeasure(widthMeasureSpec, heightMeasureSpec); mPrivateFlags3 &= ~PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT; } else { long value = mMeasureCache.valueAt(cacheIndex); // Casting a long to int drops the high 32 bits, no mask needed setMeasuredDimensionRaw((int) (value >> 32), (int) value); mPrivateFlags3 |= PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT; } // flag not set, setMeasuredDimension() was not invoked, we raise // an exception to warn the developer if ((mPrivateFlags & PFLAG_MEASURED_DIMENSION_SET) != PFLAG_MEASURED_DIMENSION_SET) { throw new IllegalStateException("View with id " + getId() + ": " + getClass().getName() + "#onMeasure() did not set the" + " measured dimension by calling" + " setMeasuredDimension()"); } mPrivateFlags |= PFLAG_LAYOUT_REQUIRED; } mOldWidthMeasureSpec = widthMeasureSpec; mOldHeightMeasureSpec = heightMeasureSpec; mMeasureCache.put(key, ((long) mMeasuredWidth) << 32 | (long) mMeasuredHeight & 0xffffffffL); // suppress sign extension }
执行onMeasure()，这个就是自定义View的重写方法onMeasure()
/** 绘制V10， * <p> * Measure the view and its content to determine the measured width and the测量视图及其内容以确定测量的宽度和 * measured height. This method is invoked by {@link #measure(int, int)} and测量高度。此方法由{@link #measure（int，int）}和 * should be overridden by subclasses to provide accurate and efficient应该被子类覆盖以提供准确和有效的 * measurement of their contents.测量其内容。 * </p> * * <p> * <strong>CONTRACT:</strong> When overriding this method, you * <em>must</em> call {@link #setMeasuredDimension(int, int)} to store the * measured width and height of this view. Failure to do so will trigger an * <code>IllegalStateException</code>, thrown by * {@link #measure(int, int)}. Calling the superclass' * {@link #onMeasure(int, int)} is a valid use. * </p> * * <p> * The base class implementation of measure defaults to the background size, * unless a larger size is allowed by the MeasureSpec. Subclasses should * override {@link #onMeasure(int, int)} to provide better measurements of * their content. * </p> * * <p> * If this method is overridden, it is the subclass's responsibility to make * sure the measured height and width are at least the view's minimum height * and width ({@link #getSuggestedMinimumHeight()} and * {@link #getSuggestedMinimumWidth()}). * </p> * * @param widthMeasureSpec horizontal space requirements as imposed by the parent. * The requirements are encoded with * {@link android.view.View.MeasureSpec}. * @param heightMeasureSpec vertical space requirements as imposed by the parent. * The requirements are encoded with * {@link android.view.View.MeasureSpec}. * * @see #getMeasuredWidth() * @see #getMeasuredHeight() * @see #setMeasuredDimension(int, int) * @see #getSuggestedMinimumHeight() * @see #getSuggestedMinimumWidth() * @see android.view.View.MeasureSpec#getMode(int) * @see android.view.View.MeasureSpec#getSize(int) */ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec), getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec)); }
其中MeasureSpec定义的常量
private static final int MODE_MASK = 0x3 << MODE_SHIFT;//将int数据的前面2个bit用于区分不同的布局模式，后面30个bit存放的是尺寸的数据
第二部，摆放
//绘制V11，摆放 private void performLayout(WindowManager.LayoutParams lp, int desiredWindowWidth, int desiredWindowHeight) { mLayoutRequested = false; mScrollMayChange = true; mInLayout = true; final View host = mView; if (host == null) { return; } if (DEBUG_ORIENTATION || DEBUG_LAYOUT) { Log.v(mTag, "Laying out " + host + " to (" + host.getMeasuredWidth() + ", " + host.getMeasuredHeight() + ")"); } Trace.traceBegin(Trace.TRACE_TAG_VIEW, "layout"); try { host.layout(0, 0, host.getMeasuredWidth(), host.getMeasuredHeight());//摆放 mInLayout = false; int numViewsRequestingLayout = mLayoutRequesters.size(); if (numViewsRequestingLayout > 0) { // requestLayout() was called during layout. // If no layout-request flags are set on the requesting views, there is no problem. // If some requests are still pending, then we need to clear those flags and do // a full request/measure/layout pass to handle this situation. ArrayList<View> validLayoutRequesters = getValidLayoutRequesters(mLayoutRequesters, false); if (validLayoutRequesters != null) { // Set this flag to indicate that any further requests are happening during // the second pass, which may result in posting those requests to the next // frame instead mHandlingLayoutInLayoutRequest = true; // Process fresh layout requests, then measure and layout int numValidRequests = validLayoutRequesters.size(); for (int i = 0; i < numValidRequests; ++i) { final View view = validLayoutRequesters.get(i); Log.w("View", "requestLayout() improperly called by " + view + " during layout: running second layout pass"); view.requestLayout(); } measureHierarchy(host, lp, mView.getContext().getResources(), desiredWindowWidth, desiredWindowHeight); mInLayout = true; host.layout(0, 0, host.getMeasuredWidth(), host.getMeasuredHeight()); mHandlingLayoutInLayoutRequest = false; // Check the valid requests again, this time without checking/clearing the // layout flags, since requests happening during the second pass get noop'd validLayoutRequesters = getValidLayoutRequesters(mLayoutRequesters, true); if (validLayoutRequesters != null) { final ArrayList<View> finalRequesters = validLayoutRequesters; // Post second-pass requests to the next frame getRunQueue().post(new Runnable() { @Override public void run() { int numValidRequests = finalRequesters.size(); for (int i = 0; i < numValidRequests; ++i) { final View view = finalRequesters.get(i); Log.w("View", "requestLayout() improperly called by " + view + " during second layout pass: posting in next frame"); view.requestLayout(); } } }); } } } } finally { Trace.traceEnd(Trace.TRACE_TAG_VIEW); } mInLayout = false; }
调用到View.layout()
/** 绘制V12，为视图及其所有后代指定大小和位置 * Assign a size and position to a view and all of its * descendants * * <p>This is the second phase of the layout mechanism. * (The first is measuring). In this phase, each parent calls * layout on all of its children to position them. * This is typically done using the child measurements * that were stored in the measure pass().</p> * * <p>Derived classes should not override this method. * Derived classes with children should override * onLayout. In that method, they should * call layout on each of their children.</p> * * @param l Left position, relative to parent * @param t Top position, relative to parent * @param r Right position, relative to parent * @param b Bottom position, relative to parent */ @SuppressWarnings({"unchecked"}) public void layout(int l, int t, int r, int b) { if ((mPrivateFlags3 & PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT) != 0) { onMeasure(mOldWidthMeasureSpec, mOldHeightMeasureSpec); mPrivateFlags3 &= ~PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT; } int oldL = mLeft; int oldT = mTop; int oldB = mBottom; int oldR = mRight; boolean changed = isLayoutModeOptical(mParent) ? setOpticalFrame(l, t, r, b) : setFrame(l, t, r, b); if (changed || (mPrivateFlags & PFLAG_LAYOUT_REQUIRED) == PFLAG_LAYOUT_REQUIRED) { onLayout(changed, l, t, r, b); if (shouldDrawRoundScrollbar()) { if(mRoundScrollbarRenderer == null) { mRoundScrollbarRenderer = new RoundScrollbarRenderer(this); } } else { mRoundScrollbarRenderer = null; } mPrivateFlags &= ~PFLAG_LAYOUT_REQUIRED; ListenerInfo li = mListenerInfo; if (li != null && li.mOnLayoutChangeListeners != null) { ArrayList<OnLayoutChangeListener> listenersCopy = (ArrayList<OnLayoutChangeListener>)li.mOnLayoutChangeListeners.clone(); int numListeners = listenersCopy.size(); for (int i = 0; i < numListeners; ++i) { listenersCopy.get(i).onLayoutChange(this, l, t, r, b, oldL, oldT, oldR, oldB); } } } final boolean wasLayoutValid = isLayoutValid(); mPrivateFlags &= ~PFLAG_FORCE_LAYOUT; mPrivateFlags3 |= PFLAG3_IS_LAID_OUT; if (!wasLayoutValid && isFocused()) { mPrivateFlags &= ~PFLAG_WANTS_FOCUS; if (canTakeFocus()) { // We have a robust focus, so parents should no longer be wanting focus. clearParentsWantFocus(); } else if (getViewRootImpl() == null || !getViewRootImpl().isInLayout()) { // This is a weird case. Most-likely the user, rather than ViewRootImpl, called // layout. In this case, there's no guarantee that parent layouts will be evaluated // and thus the safest action is to clear focus here. clearFocusInternal(null, /* propagate */ true, /* refocus */ false); clearParentsWantFocus(); } else if (!hasParentWantsFocus()) { // original requestFocus was likely on this view directly, so just clear focus clearFocusInternal(null, /* propagate */ true, /* refocus */ false); } // otherwise, we let parents handle re-assigning focus during their layout passes. } else if ((mPrivateFlags & PFLAG_WANTS_FOCUS) != 0) { mPrivateFlags &= ~PFLAG_WANTS_FOCUS; View focused = findFocus(); if (focused != null) { // Try to restore focus as close as possible to our starting focus. if (!restoreDefaultFocus() && !hasParentWantsFocus()) { // Give up and clear focus once we've reached the top-most parent which wants // focus. focused.clearFocusInternal(null, /* propagate */ true, /* refocus */ false); } } } if ((mPrivateFlags3 & PFLAG3_NOTIFY_AUTOFILL_ENTER_ON_LAYOUT) != 0) { mPrivateFlags3 &= ~PFLAG3_NOTIFY_AUTOFILL_ENTER_ON_LAYOUT; notifyEnterOrExitForAutoFillIfNeeded(true); } }
调用view自定义onLayout
/** 绘制13 * Called from layout when this view should在此视图应该从布局调用 * assign a size and position to each of its children.为每个孩子分配大小和位置。 * * Derived classes with children should override带子项的派生类应该覆盖 * this method and call layout on each of这个方法和每个的调用布局 * their children.他们的孩子 * @param changed This is a new size or position for this view * @param left Left position, relative to parent * @param top Top position, relative to parent * @param right Right position, relative to parent * @param bottom Bottom position, relative to parent */ protected void onLayout(boolean changed, int left, int top, int right, int bottom) { }
第三步，绘制
//绘制13，绘制 private void performDraw() { if (mAttachInfo.mDisplayState == Display.STATE_OFF && !mReportNextDraw) { return; } else if (mView == null) { return; } final boolean fullRedrawNeeded = mFullRedrawNeeded || mReportNextDraw; mFullRedrawNeeded = false; mIsDrawing = true; Trace.traceBegin(Trace.TRACE_TAG_VIEW, "draw"); boolean usingAsyncReport = false; if (mReportNextDraw && mAttachInfo.mThreadedRenderer != null && mAttachInfo.mThreadedRenderer.isEnabled()) { usingAsyncReport = true; mAttachInfo.mThreadedRenderer.setFrameCompleteCallback((long frameNr) -> { // TODO: Use the frame number pendingDrawFinished(); }); } try { boolean canUseAsync = draw(fullRedrawNeeded); //绘制 if (usingAsyncReport && !canUseAsync) { mAttachInfo.mThreadedRenderer.setFrameCompleteCallback(null); usingAsyncReport = false; } } finally { mIsDrawing = false; Trace.traceEnd(Trace.TRACE_TAG_VIEW); } // For whatever reason we didn't create a HardwareRenderer, end any // hardware animations that are now dangling if (mAttachInfo.mPendingAnimatingRenderNodes != null) { final int count = mAttachInfo.mPendingAnimatingRenderNodes.size(); for (int i = 0; i < count; i++) { mAttachInfo.mPendingAnimatingRenderNodes.get(i).endAllAnimators(); } mAttachInfo.mPendingAnimatingRenderNodes.clear(); } if (mReportNextDraw) { mReportNextDraw = false; // if we're using multi-thread renderer, wait for the window frame draws if (mWindowDrawCountDown != null) { try { mWindowDrawCountDown.await(); } catch (InterruptedException e) { Log.e(mTag, "Window redraw count down interrupted!"); } mWindowDrawCountDown = null; } if (mAttachInfo.mThreadedRenderer != null) { mAttachInfo.mThreadedRenderer.setStopped(mStopped); } if (LOCAL_LOGV) { Log.v(mTag, "FINISHED DRAWING: " + mWindowAttributes.getTitle()); } if (mSurfaceHolder != null && mSurface.isValid()) { SurfaceCallbackHelper sch = new SurfaceCallbackHelper(this::postDrawFinished); SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks(); sch.dispatchSurfaceRedrawNeededAsync(mSurfaceHolder, callbacks); } else if (!usingAsyncReport) { if (mAttachInfo.mThreadedRenderer != null) { mAttachInfo.mThreadedRenderer.fence(); } pendingDrawFinished(); } } }
实际绘制
//绘制14，这个跟measure和layout不同的是这个是dispatchDraw来实现的 private boolean draw(boolean fullRedrawNeeded) { Surface surface = mSurface; if (!surface.isValid()) { return false; } if (DEBUG_FPS) { trackFPS(); } 。。。 boolean useAsyncReport = false; if (!dirty.isEmpty() || mIsAnimating || accessibilityFocusDirty) { if (mAttachInfo.mThreadedRenderer != null && mAttachInfo.mThreadedRenderer.isEnabled()) { // If accessibility focus moved, always invalidate the root. boolean invalidateRoot = accessibilityFocusDirty || mInvalidateRootRequested; mInvalidateRootRequested = false; // Draw with hardware renderer. mIsAnimating = false; if (mHardwareYOffset != yOffset || mHardwareXOffset != xOffset) { mHardwareYOffset = yOffset; mHardwareXOffset = xOffset; invalidateRoot = true; } if (invalidateRoot) { mAttachInfo.mThreadedRenderer.invalidateRoot(); } dirty.setEmpty(); // Stage the content drawn size now. It will be transferred to the renderer // shortly before the draw commands get send to the renderer. final boolean updated = updateContentDrawBounds(); if (mReportNextDraw) { // report next draw overrides setStopped() // This value is re-sync'd to the value of mStopped // in the handling of mReportNextDraw post-draw. mAttachInfo.mThreadedRenderer.setStopped(false); } if (updated) { requestDrawWindow(); } useAsyncReport = true; // draw(...) might invoke post-draw, which might register the next callback already. final FrameDrawingCallback callback = mNextRtFrameCallback; mNextRtFrameCallback = null; mAttachInfo.mThreadedRenderer.draw(mView, mAttachInfo, this, callback); } else { // If we get here with a disabled & requested hardware renderer, something went // wrong (an invalidate posted right before we destroyed the hardware surface // for instance) so we should just bail out. Locking the surface with software // rendering at this point would lock it forever and prevent hardware renderer // from doing its job when it comes back. // Before we request a new frame we must however attempt to reinitiliaze the // hardware renderer if it's in requested state. This would happen after an // eglTerminate() for instance. if (mAttachInfo.mThreadedRenderer != null && !mAttachInfo.mThreadedRenderer.isEnabled() && mAttachInfo.mThreadedRenderer.isRequested() && mSurface.isValid()) { try { mAttachInfo.mThreadedRenderer.initializeIfNeeded( mWidth, mHeight, mAttachInfo, mSurface, surfaceInsets); } catch (OutOfResourcesException e) { handleOutOfResourcesException(e); return false; } mFullRedrawNeeded = true; scheduleTraversals(); return false; } //draw.... if (!drawSoftware(surface, mAttachInfo, xOffset, yOffset, scalingRequired, dirty, surfaceInsets)) { return false; } } } if (animating) { mFullRedrawNeeded = true; scheduleTraversals(); } return useAsyncReport; }
调用ViewRootImpl.drawSoftware()
/** * @return true if drawing was successful, false if an error occurred */ private boolean drawSoftware(Surface surface, AttachInfo attachInfo, int xoff, int yoff, boolean scalingRequired, Rect dirty, Rect surfaceInsets) { // Draw with software renderer. final Canvas canvas; // We already have the offset of surfaceInsets in xoff, yoff and dirty region, // therefore we need to add it back when moving the dirty region. int dirtyXOffset = xoff; int dirtyYOffset = yoff; if (surfaceInsets != null) { dirtyXOffset += surfaceInsets.left; dirtyYOffset += surfaceInsets.top; } try { dirty.offset(-dirtyXOffset, -dirtyYOffset); final int left = dirty.left; final int top = dirty.top; final int right = dirty.right; final int bottom = dirty.bottom; canvas = mSurface.lockCanvas(dirty); // The dirty rectangle can be modified by Surface.lockCanvas() //noinspection ConstantConditions if (left != dirty.left || top != dirty.top || right != dirty.right || bottom != dirty.bottom) { attachInfo.mIgnoreDirtyState = true; } // TODO: Do this in native canvas.setDensity(mDensity); } catch (Surface.OutOfResourcesException e) { handleOutOfResourcesException(e); return false; } catch (IllegalArgumentException e) { Log.e(mTag, "Could not lock surface", e); // Don't assume this is due to out of memory, it could be // something else, and if it is something else then we could // kill stuff (or ourself) for no reason. mLayoutRequested = true; // ask wm for a new surface next time. return false; } finally { dirty.offset(dirtyXOffset, dirtyYOffset); // Reset to the original value. } try { if (DEBUG_ORIENTATION || DEBUG_DRAW) { Log.v(mTag, "Surface " + surface + " drawing to bitmap w=" + canvas.getWidth() + ", h=" + canvas.getHeight()); //canvas.drawARGB(255, 255, 0, 0); } // If this bitmap's format includes an alpha channel, we // need to clear it before drawing so that the child will // properly re-composite its drawing on a transparent // background. This automatically respects the clip/dirty region // or // If we are applying an offset, we need to clear the area // where the offset doesn't appear to avoid having garbage // left in the blank areas. if (!canvas.isOpaque() || yoff != 0 || xoff != 0) { canvas.drawColor(0, PorterDuff.Mode.CLEAR); } dirty.setEmpty(); mIsAnimating = false; mView.mPrivateFlags |= View.PFLAG_DRAWN; if (DEBUG_DRAW) { Context cxt = mView.getContext(); Log.i(mTag, "Drawing: package:" + cxt.getPackageName() + ", metrics=" + cxt.getResources().getDisplayMetrics() + ", compatibilityInfo=" + cxt.getResources().getCompatibilityInfo()); } try { canvas.translate(-xoff, -yoff); if (mTranslator != null) { mTranslator.translateCanvas(canvas); } canvas.setScreenDensity(scalingRequired ? mNoncompatDensity : 0); attachInfo.mSetIgnoreDirtyState = false; mView.draw(canvas);//绘制 drawAccessibilityFocusedDrawableIfNeeded(canvas); } finally { if (!attachInfo.mSetIgnoreDirtyState) { // Only clear the flag if it was not set during the mView.draw() call attachInfo.mIgnoreDirtyState = false; } } } finally { try { surface.unlockCanvasAndPost(canvas); } catch (IllegalArgumentException e) { Log.e(mTag, "Could not unlock surface", e); mLayoutRequested = true; // ask wm for a new surface next time. //noinspection ReturnInsideFinallyBlock return false; } if (LOCAL_LOGV) { Log.v(mTag, "Surface " + surface + " unlockCanvasAndPost"); } } return true; }
调用View.draw()进行实际绘制
/** 绘制到画布 * Manually render this view (and all of its children) to the given Canvas. * The view must have already done a full layout before this function is * called. When implementing a view, implement * {@link #onDraw(android.graphics.Canvas)} instead of overriding this method. * If you do need to override this method, call the superclass version. * * @param canvas The Canvas to which the View is rendered. */ @CallSuper public void draw(Canvas canvas) { final int privateFlags = mPrivateFlags; final boolean dirtyOpaque = (privateFlags & PFLAG_DIRTY_MASK) == PFLAG_DIRTY_OPAQUE && (mAttachInfo == null || !mAttachInfo.mIgnoreDirtyState); mPrivateFlags = (privateFlags & ~PFLAG_DIRTY_MASK) | PFLAG_DRAWN; /* * Draw traversal performs several drawing steps which must be executed * in the appropriate order: * * 1. Draw the background * 2. If necessary, save the canvas' layers to prepare for fading * 3. Draw view's content * 4. Draw children * 5. If necessary, draw the fading edges and restore layers * 6. Draw decorations (scrollbars for instance) */ // Step 1, draw the background, if needed 步骤1，绘制背景 int saveCount; if (!dirtyOpaque) { drawBackground(canvas);//绘制背景 } // skip step 2 & 5 if possible (common case) final int viewFlags = mViewFlags; boolean horizontalEdges = (viewFlags & FADING_EDGE_HORIZONTAL) != 0; boolean verticalEdges = (viewFlags & FADING_EDGE_VERTICAL) != 0; if (!verticalEdges && !horizontalEdges) { // Step 3, draw the content 绘制View内容 if (!dirtyOpaque) onDraw(canvas); // Step 4, draw the children 绘制子View dispatchDraw(canvas); drawAutofilledHighlight(canvas); // Overlay is part of the content and draws beneath Foreground if (mOverlay != null && !mOverlay.isEmpty()) { mOverlay.getOverlayView().dispatchDraw(canvas); } // Step 6, draw decorations (foreground, scrollbars) 绘制前景 onDrawForeground(canvas); // Step 7, draw the default focus highlight 绘制默认光标高亮 drawDefaultFocusHighlight(canvas); if (debugDraw()) { debugDrawFocus(canvas); } // we're done... return; } /* * Here we do the full fledged routine... * (this is an uncommon case where speed matters less, * this is why we repeat some of the tests that have been * done above) */ boolean drawTop = false; boolean drawBottom = false; boolean drawLeft = false; boolean drawRight = false; float topFadeStrength = 0.0f; float bottomFadeStrength = 0.0f; float leftFadeStrength = 0.0f; float rightFadeStrength = 0.0f; // Step 2, save the canvas' layers int paddingLeft = mPaddingLeft; final boolean offsetRequired = isPaddingOffsetRequired(); if (offsetRequired) { paddingLeft += getLeftPaddingOffset(); } int left = mScrollX + paddingLeft; int right = left + mRight - mLeft - mPaddingRight - paddingLeft; int top = mScrollY + getFadeTop(offsetRequired); int bottom = top + getFadeHeight(offsetRequired); if (offsetRequired) { right += getRightPaddingOffset(); bottom += getBottomPaddingOffset(); } final ScrollabilityCache scrollabilityCache = mScrollCache; final float fadeHeight = scrollabilityCache.fadingEdgeLength; int length = (int) fadeHeight; // clip the fade length if top and bottom fades overlap // overlapping fades produce odd-looking artifacts if (verticalEdges && (top + length > bottom - length)) { length = (bottom - top) / 2; } // also clip horizontal fades if necessary if (horizontalEdges && (left + length > right - length)) { length = (right - left) / 2; } if (verticalEdges) { topFadeStrength = Math.max(0.0f, Math.min(1.0f, getTopFadingEdgeStrength())); drawTop = topFadeStrength * fadeHeight > 1.0f; bottomFadeStrength = Math.max(0.0f, Math.min(1.0f, getBottomFadingEdgeStrength())); drawBottom = bottomFadeStrength * fadeHeight > 1.0f; } if (horizontalEdges) { leftFadeStrength = Math.max(0.0f, Math.min(1.0f, getLeftFadingEdgeStrength())); drawLeft = leftFadeStrength * fadeHeight > 1.0f; rightFadeStrength = Math.max(0.0f, Math.min(1.0f, getRightFadingEdgeStrength())); drawRight = rightFadeStrength * fadeHeight > 1.0f; } saveCount = canvas.getSaveCount(); int solidColor = getSolidColor(); if (solidColor == 0) { if (drawTop) { canvas.saveUnclippedLayer(left, top, right, top + length); } if (drawBottom) { canvas.saveUnclippedLayer(left, bottom - length, right, bottom); } if (drawLeft) { canvas.saveUnclippedLayer(left, top, left + length, bottom); } if (drawRight) { canvas.saveUnclippedLayer(right - length, top, right, bottom); } } else { scrollabilityCache.setFadeColor(solidColor); } // Step 3, draw the content if (!dirtyOpaque) onDraw(canvas); // Step 4, draw the children 绘制子 dispatchDraw(canvas); // Step 5, draw the fade effect and restore layers final Paint p = scrollabilityCache.paint; final Matrix matrix = scrollabilityCache.matrix; final Shader fade = scrollabilityCache.shader; if (drawTop) { matrix.setScale(1, fadeHeight * topFadeStrength); matrix.postTranslate(left, top); fade.setLocalMatrix(matrix); p.setShader(fade); canvas.drawRect(left, top, right, top + length, p); } if (drawBottom) { matrix.setScale(1, fadeHeight * bottomFadeStrength); matrix.postRotate(180); matrix.postTranslate(left, bottom); fade.setLocalMatrix(matrix); p.setShader(fade); canvas.drawRect(left, bottom - length, right, bottom, p); } if (drawLeft) { matrix.setScale(1, fadeHeight * leftFadeStrength); matrix.postRotate(-90); matrix.postTranslate(left, top); fade.setLocalMatrix(matrix); p.setShader(fade); canvas.drawRect(left, top, left + length, bottom, p); } if (drawRight) { matrix.setScale(1, fadeHeight * rightFadeStrength); matrix.postRotate(90); matrix.postTranslate(right, top); fade.setLocalMatrix(matrix); p.setShader(fade); canvas.drawRect(right - length, top, right, bottom, p); } canvas.restoreToCount(saveCount); drawAutofilledHighlight(canvas); // Overlay is part of the content and draws beneath Foreground if (mOverlay != null && !mOverlay.isEmpty()) { mOverlay.getOverlayView().dispatchDraw(canvas); } // Step 6, draw decorations (foreground, scrollbars) onDrawForeground(canvas); if (debugDraw()) { debugDrawFocus(canvas); } }
大概就完了。。。。。
所以view是怎么绘制出来的？
1）在ActivityThread.handleLauncherActivity()方法中，创建Activity、ViewRootImpl对象；
2）在ActivityThread.handleResumeActivity()方法中，在onResume()后，关联Activity和DecorView对象，然后调用WindowManager.addView()把DecorView添加到WindowManager；
3)Handler调用线程，调起ViewRootImpl.performTraversals()方法，方法内依次调用View的
测量、摆放、绘制方法。
好像愈发简单了点。。。。
2022年06月03日19:17:44
以此来看，Activity层级结构如下：activity.png
2022年06月03日21:54:39
senRsl
2019年05月17日17:19:53
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