Android WindowContainer窗口结构

Android窗口是根据显示屏幕来管理，每个显示屏幕的窗口层级分为37层，0-36层。每层可以放置多个窗口，上层窗口覆盖下面的。

  要理解窗口的结构，需要学习下WindowContainer、RootWindowContainer、DisplayContent、TaskDisplayArea、Task、ActivityRecord、WindowToken、WindowState

WindowContainer等类。

WindowContainer类

  为直接包含窗口或者通过孩子层级形式包含窗口的类，定义了普遍功能。它作为基类被继承，像RootWindowContainer、DisplayContent、TaskDisplayArea、Task、ActivityRecord、WindowToken、WindowState都是直接或间接的继承该类。

class WindowContainer<E extends WindowContainer> extends ConfigurationContainer<E>implements Comparable<WindowContainer>, Animatable, SurfaceFreezer.Freezable {……// List of children for this window container. List is in z-order as the children appear on// screen with the top-most window container at the tail of the list.protected final WindowList<E> mChildren = new WindowList<E>();            ……}

窗口结构层级相关类

  先上一张没添加特色模式窗口结构图：

该图是未添加特色模式时的结构图，添加特色模式之后的结构，更复杂。

  RootWindowContainer：根窗口容器，树的根是它。通过它遍历寻找，可以找到窗口树上的窗口。它的孩子是DisplayContent。

  DisplayContent：该类是对应着显示屏幕的，Android是支持多屏幕的，所以可能存在多个DisplayContent对象。上图只画了一个对象的结构，其他对象的结构也是和画的对象的结构是相似的。

  TaskDisplayArea：它为DisplayContent的孩子，对应着窗口层次的第2层。第2层作为应用层，看它的定义：int APPLICATION_LAYER = 2，应用层的窗口是处于第2层。TaskDisplayArea的孩子是Task类，其实它的孩子类型也可以是TaskDisplayArea。而Task的孩子则可以是ActivityRecord，也可以是Task。

  Tokens：它为DisplayContent的孩子，它的孩子是WindowToken。而WindowToken的孩子则为WindowState对象。WindowState是对应着一个窗口的。结构图中，DisplayContent不止包含一个Tokens，还有两个。其实ImeContainer也是继承自Tokens。

  ImeContainer：它也为DisplayContent的孩子，它是输入法窗口的容器，它的孩子是WindowToken类型。WindowToken的孩子为WindowState类型，而WindowState类型则对应着输入法窗口。

  Task：任务，它的孩子可以是Task，也可以是ActivityRecord类型。

  ActivityRecord：是对应着应用进程中的Activity的。ActivityRecord是继承WindowToken的，它的孩子类型为WindowState。

  WindowState：WindowState是对应着一个窗口的。

  结构图中，DisplayContent有5个孩子。图中从上到下，第一个是Tokens，对应着窗口图层0、1。第二个是TaskDisplayArea，对应着窗口图层2。第三个是Tokens，对应着窗口图层3到14。第四个是ImeContainer，对应着窗口图层15到16。第五个是Tokens，对应着窗口图层17到36。

Activity添加窗口过程

@frameworks/base/core/java/android/app/ActivityOptions.java
ActivityOptions(Bundle opts) {private static final String KEY_AVOID_MOVE_TO_FRONT = "android.activity.avoidMoveToFront";mAvoidMoveToFront = opts.getBoolean(KEY_AVOID_MOVE_TO_FRONT, false);@frameworks/base/services/core/java/com/android/server/wm/ActivityStarter.java
startActivityInnerSlog.w(TAG, "xww startActivityInner, targetTask=" + targetTask + " r=" + r + " sourceRecord=" + sourceRecord); //xww startActivityInner, targetTask=null r=ActivityRecord{44c341e u0 com.xxx.launcher/.MainActivity t2} sourceRecord=nullif (!mAvoidMoveToFront && mDoResume) {  mTargetRootTask.getRootTask().moveToFront("reuseOrNewTask", targetTask);  }        
@frameworks/base/services/core/java/com/android/server/wm/Task.javamoveToFrontSlog.w(TAG, "xww moveToFront 3, task=" + task + " reason=" + reason);  //xww moveToFront 3, task=null reason=reuseOrNewTaskmoveToFrontInner(reason, task);
@frameworks/base/services/core/java/com/android/server/wm/TaskDisplayArea.javatask.getParent().positionChildAt(POSITION_TOP, task, true /* includingParents */);Slog.w(TAG, "xww positionChildAt 3aa, child.asTask()=" + child.asTask());//xww positionChildAt 3aa, child.asTask()=Task{7862cf6 #6 type=standard A=1000:com.xxx.launcher U=0 visible=true visibleRequested=false mode=fullscreen translucent=true sz=1}positionChildTaskAt(position, child.asTask(), includingParents);if (includingParents && getParent() != null && (moveToTop || moveToBottom)) {Slog.w(TAG, "xww positionChildAt 6, this=" + this + " getParent()=" + getParent().toString());getParent().positionChildAt(moveToTop ? POSITION_TOP : POSITION_BOTTOM, this /* child */, true /* includingParents */);
@frameworks/base/services/core/java/com/android/server/wm/DisplayArea.javaif (includingParents && parent != null && (position == POSITION_TOP || position == POSITION_BOTTOM)) {Slog.w(TAG, "xww positionChildAt 18, this=" + this);parent.positionChildAt(position, this /* child */, true /* includingParents */);
@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.javacase POSITION_TOP:  Slog.w(TAG, "xww addChild 4 child=" + child.toString() + " position=" + position + " this=" + this.toString());mChildren.add(child);  //ww addChild 4 child=Display{#2 state=ON size=1920x1080 ROTATION_0 name=avd_launcher} position=2147483647 this=com.android.server.wm.RootWindowContainer@973f7ec
@frameworks/base/services/core/java/com/android/server/wm/Task.java                                            mTargetRootTask.startActivityLocked(mStartActivity, topRootTask != null ? topRootTask.getTopNonFinishingActivity() : null, newTask, isTaskSwitch, mOptions, sourceRecord);if (!r.mLaunchTaskBehind && allowMoveToFront && (!isOrhasTask || newTask)) {  positionChildAtTop(rTask);
@frameworks/base/services/core/java/com/android/server/wm/Task.java    moveToFront("positionChildAtTop");@frameworks/base/services/core/java/com/android/server/wm/InputMonitor.java
populateInputWindowHandle
@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.javafinal boolean focusable = w.canReceiveKeys() && (mService.mPerDisplayFocusEnabled || mDisplayContent.isOnTop());Slog.w(TAG, "xww isOnTop 3, this=" + toString() + " parent=" + (parent == null ? "null" : parent.toString()) + " parent.getTopChild()=" + (parent.getTopChild() == null ? "null" : parent.getTopChild().toString()));if(parent != null){for (int i = parent.mChildren.size() - 1; i >= 0; --i) {Object child = parent.mChildren.get(i);Slog.w(TAG, "xww isOnTop, i=" + i + ", child=" + child.toString());}}        return parent != null && parent.getTopChild() == this && parent.isOnTop();//isOnTop 3, this=Display{#3 state=ON size=1920x1080 ROTATION_0 name=avd_launcher} parent=com.android.server.wm.RootWindowContainer@bf43992 parent.getTopChild()=Display{#3 state=ON size=1920x1080 ROTATION_0 name=avd_launcher}
@frameworks/base/services/core/java/com/android/server/wm/WindowList.java        return mChildren.peekLast();return size() > 0 ? get(size() - 1) : null;
@frameworks/base/services/core/java/com/android/server/wm/RootWindowContainer.javaparent.isOnTop()   //parent=com.android.server.wm.RootWindowContainer@bf43992return true;

addWindowToken流程

@frameworks/base/services/core/java/com/android/server/wm/DisplayContent.java
addWindowToken
@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.javada.addChild(token);Slog.w(TAG, "xww addChild 2 child=" + child.toString() + " this=" + this.toString());  //xww addChild 2 child=WindowToken{a0b2c76 android.os.Binder@9f68311} this=Leaf:3:[e-mail](positionToAdd, child);@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java        
addChildSlog.w(TAG, "xww addChild 3 child=" + child.toString() + " index=" + index + " this=" + this.toString());mChildren.add(index, child);

打印窗口信息

@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java    void FindChildInfo(E node, String indent){Slog.w(TAG, "FindMeshInfo: node=" + indent + "|--" + node + ", size=" + node.mChildren.size());if(node.mChildren.size() == 0){return;}}void FindChild(E node, String indent){indent += "|  ";FindChildInfo(node, indent);for(int i = 0; i < node.mChildren.size(); i++){FindChild((E)node.mChildren.get(i), indent);}}@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java
positionChildAtswitch (position) {case POSITION_TOP:if(child.toString().contains("avd_launcher")){String str = new String();Slog.w(TAG, "xww addChild xxxxx begin");this.FindChild((E)this, str);Slog.w(TAG, "xww addChild xxxxx end");}

    FindMeshInfo: node=|  |--com.android.server.wm.RootWindowContainer@58ef5a3, size=xxxFindMeshInfo: node=|  |  |--Display{#4 state=ON size=1920x1080 ROTATION_0 name=avd_launcher}, size=4FindMeshInfo: node=|  |  |  |--WindowedMagnification:0:31@251785581, size=7FindMeshInfo: node=|  |  |  |  |--FullscreenMagnification:0:14@45167010, size=3FindMeshInfo: node=|  |  |  |  |  |--Leaf:0:1@131968563, size=0FindMeshInfo: node=|  |  |  |  |  |--DefaultTaskDisplayArea@48817648, size=1FindMeshInfo: node=|  |  |  |  |  |  |--Task{e9e1c50 #8 type=standard A=1000:com.xxx.launcher U=0 visible=true visibleRequested=false mode=fullscreen translucent=true sz=1}, size=1FindMeshInfo: node=|  |  |  |  |  |  |  |--ActivityRecord{bd29e49 u0 com.xxx.launcher/.MainActivity t8}, size=0FindMeshInfo: node=|  |  |  |  |  |--Leaf:3:14@182007657, size=0FindMeshInfo: node=|  |  |  |  |--ImePlaceholder:15:16@26527214, size=1FindMeshInfo: node=|  |  |  |  |  |--ImeContainer@79362703, size=0FindMeshInfo: node=|  |  |  |  |--FullscreenMagnification:17:23@93221148, size=1FindMeshInfo: node=|  |  |  |  |  |--Leaf:17:23@197452069, size=0FindMeshInfo: node=|  |  |  |  |--Leaf:24:25@118182650, size=0FindMeshInfo: node=|  |  |  |  |--FullscreenMagnification:26:27@175550635, size=1FindMeshInfo: node=|  |  |  |  |  |--Leaf:26:27@228557576, size=0FindMeshInfo: node=|  |  |  |  |--Leaf:28:28@117926561, size=0FindMeshInfo: node=|  |  |  |  |--FullscreenMagnification:29:31@170632390, size=1FindMeshInfo: node=|  |  |  |  |  |--Leaf:29:31@133016711, size=0FindMeshInfo: node=|  |  |  |--Leaf:32:32@36554676, size=0FindMeshInfo: node=|  |  |  |--FullscreenMagnification:33:35@160370653, size=1FindMeshInfo: node=|  |  |  |  |--Leaf:33:35@179128146, size=0FindMeshInfo: node=|  |  |  |--Leaf:36:36@49187363, size=0

@frameworks/base/core/java/android/app/ActivityOptions.java
ActivityOptions(Bundle opts) {
    private static final String KEY_AVOID_MOVE_TO_FRONT = "android.activity.avoidMoveToFront";
    mAvoidMoveToFront = opts.getBoolean(KEY_AVOID_MOVE_TO_FRONT, false);

@frameworks/base/services/core/java/com/android/server/wm/ActivityStarter.java
startActivityInner
    Slog.w(TAG, "xww startActivityInner, targetTask=" + targetTask + " r=" + r + " sourceRecord=" + sourceRecord); //xww startActivityInner, targetTask=null r=ActivityRecord{44c341e u0 com.xxx.launcher/.MainActivity t2} sourceRecord=null
    if (!mAvoidMoveToFront && mDoResume) {  mTargetRootTask.getRootTask().moveToFront("reuseOrNewTask", targetTask);  }        
@frameworks/base/services/core/java/com/android/server/wm/Task.java
        moveToFront
        Slog.w(TAG, "xww moveToFront 3, task=" + task + " reason=" + reason);  //xww moveToFront 3, task=null reason=reuseOrNewTask
            moveToFrontInner(reason, task);
@frameworks/base/services/core/java/com/android/server/wm/TaskDisplayArea.java
                task.getParent().positionChildAt(POSITION_TOP, task, true /* includingParents */);
                    Slog.w(TAG, "xww positionChildAt 3aa, child.asTask()=" + child.asTask());
                    //xww positionChildAt 3aa, child.asTask()=Task{7862cf6 #6 type=standard A=1000:com.xxx.launcher U=0 visible=true visibleRequested=false mode=fullscreen translucent=true sz=1}
                    positionChildTaskAt(position, child.asTask(), includingParents);
                        if (includingParents && getParent() != null && (moveToTop || moveToBottom)) {
                            Slog.w(TAG, "xww positionChildAt 6, this=" + this + " getParent()=" + getParent().toString());
                            getParent().positionChildAt(moveToTop ? POSITION_TOP : POSITION_BOTTOM, this /* child */, true /* includingParents */);
@frameworks/base/services/core/java/com/android/server/wm/DisplayArea.java
                                if (includingParents && parent != null && (position == POSITION_TOP || position == POSITION_BOTTOM)) {
                                    Slog.w(TAG, "xww positionChildAt 18, this=" + this);
                                    parent.positionChildAt(position, this /* child */, true /* includingParents */);
@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java
                                        case POSITION_TOP:  
                                            Slog.w(TAG, "xww addChild 4 child=" + child.toString() + " position=" + position + " this=" + this.toString());
                                            mChildren.add(child);  //ww addChild 4 child=Display{#2 state=ON size=1920x1080 ROTATION_0 name=avd_launcher} position=2147483647 this=com.android.server.wm.RootWindowContainer@973f7ec
@frameworks/base/services/core/java/com/android/server/wm/Task.java                                            
    mTargetRootTask.startActivityLocked(mStartActivity, topRootTask != null ? topRootTask.getTopNonFinishingActivity() : null, newTask, isTaskSwitch, mOptions, sourceRecord);
        if (!r.mLaunchTaskBehind && allowMoveToFront && (!isOrhasTask || newTask)) {  positionChildAtTop(rTask);
@frameworks/base/services/core/java/com/android/server/wm/Task.java    
            moveToFront("positionChildAtTop");

@frameworks/base/services/core/java/com/android/server/wm/InputMonitor.java
populateInputWindowHandle
@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java
    final boolean focusable = w.canReceiveKeys() && (mService.mPerDisplayFocusEnabled || mDisplayContent.isOnTop());
        Slog.w(TAG, "xww isOnTop 3, this=" + toString() + " parent=" + (parent == null ? "null" : parent.toString()) + " parent.getTopChild()=" + (parent.getTopChild() == null ? "null" : parent.getTopChild().toString()));
        if(parent != null){
            for (int i = parent.mChildren.size() - 1; i >= 0; --i) {
                Object child = parent.mChildren.get(i);
                Slog.w(TAG, "xww isOnTop, i=" + i + ", child=" + child.toString());
            }
        }        
        return parent != null && parent.getTopChild() == this && parent.isOnTop();
        //isOnTop 3, this=Display{#3 state=ON size=1920x1080 ROTATION_0 name=avd_launcher} parent=com.android.server.wm.RootWindowContainer@bf43992 parent.getTopChild()=Display{#3 state=ON size=1920x1080 ROTATION_0 name=avd_launcher}
@frameworks/base/services/core/java/com/android/server/wm/WindowList.java        
            return mChildren.peekLast();
                return size() > 0 ? get(size() - 1) : null;
@frameworks/base/services/core/java/com/android/server/wm/RootWindowContainer.java
            parent.isOnTop()   //parent=com.android.server.wm.RootWindowContainer@bf43992
                return true;

@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java    
    void FindChildInfo(E node, String indent){
        Slog.w(TAG, "FindMeshInfo: node=" + indent + "|--" + node + ", size=" + node.mChildren.size());
        if(node.mChildren.size() == 0){
            return;
        }
    }

    void FindChild(E node, String indent){
        indent += "|  ";
        FindChildInfo(node, indent);
        for(int i = 0; i < node.mChildren.size(); i++){
            FindChild((E)node.mChildren.get(i), indent);
        }
    }
    
@frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java
positionChildAt
    switch (position) {
    case POSITION_TOP:
        if(child.toString().contains("avd_launcher")){
                String str = new String();
                Slog.w(TAG, "xww addChild xxxxx begin");
                this.FindChild((E)this, str);
                Slog.w(TAG, "xww addChild xxxxx end");
        }