Window和WindowManager知识点深入解析

超、凢脫俗 2022-06-01 11:29 190阅读 0赞

关键字：Window WindowManager Android

转载请注明链接：[http://blog.csdn.net/feather\_wch/article/details/79186967][http_blog.csdn.net_feather_wch_article_details_79186967]

> 1.  以面试题形式总结Window、WindowManager所有知识点
> 2.  总结Window和WindowManager的基本使用以及概念
> 3.  分析Window的内部机制
> 4.  分析Activity、Dialog、Toast的Window创建过程

# Window和WindowManager #

版本：2018/2/13-1

--------------------

*  Window和WindowManager
    
     *  Window的内部机制
     *  Window的创建过程
     *  Dialog
     *  Toast
     *  Window源码流程图

1、Window是什么？

> 1.  表示一个窗口的概念，是所有`View`的直接管理者，任何视图都通过`Window`呈现(单击事件由Window->DecorView->View; Activity的`setContentView`底层通过`Window`完成)
> 2.  `Window`是一个抽象类，具体实现是`PhoneWindow`
> 3.  创建`Window`需要通过`WindowManager`创建
> 4.  `WindowManager`是外界访问`Window`的入口
> 5.  `Window`具体实现位于`WindowManagerService`中
> 6.  `WindowManager`和`WindowManagerService`的交互是通过`IPC`完成

2、如果通过`WindowManager`添加`Window`(代码实现)？

//1. 控件
            Button button = new Button(this);
            button.setText("Window Button");
            //2. 布局参数
            WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT,
                    WindowManager.LayoutParams.WRAP_CONTENT, 0, 0, PixelFormat.TRANSPARENT);
            layoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                    | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                    | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED;
            layoutParams.gravity = Gravity.LEFT | Gravity.TOP;
            layoutParams.x = 100;
            layoutParams.y = 300;
            // 必须要有type不然会异常: the specified window type 0 is not valid
            layoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ERROR;
            //3. 获取WindowManager并添加控件到Window中
            WindowManager windowManager = getWindowManager();
            windowManager.addView(button, layoutParams);

> 1.  注意一定要指定布局类型`layoutParams.type`
> 2.  需要动态申请`Draw over other apps`权限：[http://blog.csdn.net/feather\_wch/article/details/79185045][http_blog.csdn.net_feather_wch_article_details_79185045]

3、LayoutParams的`flags`属性

<table> 
 <thead> 
  <tr> 
   <th>Flags</th> 
   <th>解释</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>FLAG_NOT_FOCUSABLE</td> 
   <td>表示<code>Window</code>不需要焦点，会同时启用<code>FLAG_NOT_TOUCH_MODAL</code>, 最终事件会直接传递到下层具有焦点的<code>Window</code></td> 
  </tr> 
  <tr> 
   <td>FLAG_NOT_TOUCH_MODEL</td> 
   <td>将当前<code>Window</code>区域以外的单击事件传递给底层<code>Window</code>，当前区域内的单击事件自己处理(如果不开启，其他<code>Window</code>会无法收到单击事件)</td> 
  </tr> 
  <tr> 
   <td>FLAG_SHOW_WHEN_LOCKED</td> 
   <td>可以让<code>Window</code>显示在锁屏的界面上</td> 
  </tr> 
 </tbody> 
</table>

4、LayoutParams的`type`属性

<table> 
 <thead> 
  <tr> 
   <th>Window类型</th> 
   <th>含义</th> 
   <th>Window层级</th> 
   <th>Type参数</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>应用Window</td> 
   <td>对应着一个Activity</td> 
   <td>1~99(视图最下层)</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>子Window</td> 
   <td>不能单独存在，需要附属在特定的父<code>Window</code>之中(如Dialog就是子Window)</td> 
   <td>1000~1999</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>系统Window</td> 
   <td>需要声明权限才能创建的<code>Window</code>，比如<code>Toast</code>和<code>系统状态栏</code></td> 
   <td>2000~2999(视图最上层)</td> 
   <td>TYPE_SYSTEM_OVERLAY / TYPE_SYSTEM_ERROR</td> 
  </tr> 
 </tbody> 
</table>

> 需要在AndroidManifest中声明权限：`SYSTEM_ALERT_WINDOW`

5、WindowManager的三个主要功能：添加、更新、删除View

public interface ViewManager { 
        public void addView(View view, ViewGroup.LayoutParams params); //添加View
        public void updateViewLayout(View view, ViewGroup.LayoutParams params); //更新View
        public void removeView(View view); //删除View
    }

6、通过WindowManager实现拖动View的效果

> 1.  给`View`设置`onTouchListener`监听器
> 2.  在`onTouch`方法中根据当前坐标，来更新View`updateViewLayout`

mButton.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            int rawX = (int) event.getRawX();
            int rawY = (int) event.getRawY();
            switch (event.getAction()){
                case MotionEvent.ACTION_MOVE:
                    mLayoutParams.x = rawX;
                    mLayoutParams.y = rawY;
                    mWindowManager.updateViewLayout(mButton, mLayoutParams);
                    break;
            }
            return false;
        }
    });

## Window的内部机制 ##

7、Window概念解析

> 1.  Window和View通过`ViewRootImpl`建立联系
> 2.  `Window`并不是实际存在的，而是以`View`的形式存在
> 3.  `WindowManager`的三个接口方法也是针对`View`的
> 4.  实际使用中无法直接访问Window，必须通过`WindowManager`
> 5.  View是视图的呈现方式，但是不能单独存在，必须依附在`Window`这个抽象的概念上

8、Window的添加过程`addView`

> 1.  `WindowManager`是一个接口，真正实现类是`WindowManagerImpl`，并最终以代理模式交给`WindowManagerGlobal`实现

//WindowManagerImpl中的三大方法都交给WindowManangerGlobal实现
            public void addView(View view, ViewGroup.LayoutParams params) {
                applyDefaultToken(params);
                mGlobal.addView(view, params, mContext.getDisplay(), mParentWindow);
            }
            public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
                applyDefaultToken(params);
                mGlobal.updateViewLayout(view, params);
            }
            public void removeView(View view) {
                mGlobal.removeView(view, false);
            }

> 1.  `WindowManagerGlobal`的`setView`会通过`ViewRootImpl`的`setView`建立`View`和`Window`的联系

public void addView(View view, ViewGroup.LayoutParams params, Display display, Window parentWindow) {
            //1. 检查参数是否合法
            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");}
            //2. 如果是子Window会调整布局参数
            final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
            if (parentWindow != null) {
                parentWindow.adjustLayoutParamsForSubWindow(wparams);
            } else {
                //3. 如果没有父Window则根据该app的硬件加速设置，设置给该View
                ...
            }
            synchronized (mLock) {
                //...省略....
                //4. 创建Window所对应的ViewRootImpl
                ViewRootImpl root = new ViewRootImpl(view.getContext(), display);
                //5. 将Window对应的ViewRootImpl、View、布局参数添加到列表中
                view.setLayoutParams(wparams);
                mViews.add(view);//将Window对应的View添加到列表中
                mRoots.add(root);//将ViewRootImpl添加到列表中
                mParams.add(wparams);//将Window对应的布局参数添加到列表中
                //6. 通过ViewRootImpl完成View的绘制过程，以及Window的添加过程
                try {
                    root.setView(view, wparams, panelParentView);
                } catch (RuntimeException e) {
                    //...
                }
            }
        }

> 1.  通过ViewRootImpl的setView完成View的绘制过程，以及Window的添加过程

//ViewRootImpl.java
    public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
        ...
        //1. 完成异步刷新请求-进行View绘制
        requestLayout();
        ...
        //2. WindowSession的类型是IWindowSession，Binder对象(IPC调用)，真正实现类是Session
        res = mWindowSession.addToDisplay(mWindow, ...);
        ...
    }
    //ViewRootImpl.java: 完成异步刷新请求(绘制View)
    public void requestLayout() {
        if (!mHandlingLayoutInLayoutRequest) {
            checkThread();
            mLayoutRequested = true;
            //1. 实际是View绘制的入口(测量、布局、重绘)
            scheduleTraversals();
        }
    }
    //Session.java
    public int addToDisplay(IWindow window, ...) {
        //通过`WindowManagerService`实现Window的添加
        return mService.addWindow(this, window, ...);
    }

9、Window的删除过程`removeView`  
如同`addView`一样最终由`WindowManagerGlobal`实现:

//WindowManagerImpl.java
        public void removeView(View view) {
            mGlobal.removeView(view, false);
        }
        //WindowManagerGlobal.java
        public void removeView(View view, boolean immediate) {
            ...
            synchronized (mLock) {
                //1. 查询待删除的View的索引
                int index = findViewLocked(view, true);
                View curView = mRoots.get(index).getView();
                //2. 进行进一步删除
                removeViewLocked(index, immediate);
                ...
            }
        }
        //WindowManagerGlobal.java
        private void removeViewLocked(int index, boolean immediate) {
            ViewRootImpl root = mRoots.get(index);
            View view = root.getView();
            ...
            //1. ViewRoot调用die，发送删除请求后立即返回，此时View并没有完成删除
            boolean deferred = root.die(immediate);
            if (view != null) {
                view.assignParent(null);
                //2. 将View添加到等待删除的列表中
                if (deferred) {
                    mDyingViews.add(view);
                }
            }
        }
        //ViewRootImpl.java
        boolean die(boolean immediate) {
            //1. 如果是同步删除，直接调用doDie
            if (immediate && !mIsInTraversal) {
                doDie();
                return false;
            }
            //2. 如果是异步删除，发送消息。最终由Handler接收并且调用`doDie()`
            mHandler.sendEmptyMessage(MSG_DIE);
            return true;
        }
        //ViewRootImpl.java: 同步删除
        void doDie() {
            ...
            synchronized (this) {
                //1. 删除`view`
                dispatchDetachedFromWindow();
                ...
            }
            //2. 刷新数据，将Window对应的所有对象从列表中删除
            WindowManagerGlobal.getInstance().doRemoveView(this);
        }
    
        //ViewRootImpl.java: 删除View
        void dispatchDetachedFromWindow() {
            /**================================= * 1. 调用View的dispatchDetachedFromWindow * -内部会调用onDetachedFromWindow和onDetachedFromWindowInternal * -onDetachedFromWindow()在View删除时调用，可以进行：终止动画和线程等操作 *=================================*/
            if (mView != null && mView.mAttachInfo != null) {
                mAttachInfo.mTreeObserver.dispatchOnWindowAttachedChange(false);
                mView.dispatchDetachedFromWindow();
            }
            //2. 【IPC】调用`Session`的方法删除`Window`, 最终调用WMS的`removeWindow()`
            mWindowSession.remove(mWindow);
            ......
        }

> `WindowManager`中提供了两种删除接口：`removeView`异步删除、`removeViewImmediate`同步删除(不建议使用)

11、Window的更新过程`updateViewLayout`

public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
            ...
            final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams)params;
            //1. 给View设置新布局
            view.setLayoutParams(wparams);
            //2. 按照index从列表中删除旧布局，并添加新布局
            synchronized (mLock) {
                int index = findViewLocked(view, true);
                ViewRootImpl root = mRoots.get(index);
                mParams.remove(index);
                mParams.add(index, wparams);
                //3. 更新ViewRootImpl中的布局(会对View进行测量、布局、重绘，)
                root.setLayoutParams(wparams, false);
            }
        }

> 1.  和添加删除类似，最终调用`WindowManagerGlobal`的`updateViewLayout`方法
> 2.  `root.setLayoutParams`会对View进行重新布局——测量、布局、重绘
> 3.  `root.setLayoutParams`还会通过`WindowSession`更新`Window`的视图——最终通过`WindowManagerService`的`relayoutWindow()`实现(IPC)

## Window的创建过程 ##

12、Activity的启动过程  
启动最终由主线程(ActivityThread)的handleLaunchActivity()处理:

//ActivityThread.java : 处理Activity的创建
        private void handleLaunchActivity(ActivityClientRecord r, Intent customIntent, String reason) {
            //1. 创建Activity前进行初始化
            WindowManagerGlobal.initialize();
            //2. 完成整个启动过程
            Activity a = performLaunchActivity(r, customIntent);
            if (a != null) {
                //3. 内部调用onResume()
                handleResumeActivity(r.token, false, r.isForward, ......);
                ......
            }
            ......
        }
        //ActivityThread.java
        private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
            //1. 创建Context
            ContextImpl appContext = createBaseContextForActivity(r);
            //2. 类加载器创建Activity
            java.lang.ClassLoader cl = appContext.getClassLoader();
            activity = mInstrumentation.newActivity(cl, component.getClassName(), r.intent);
            //3. 创建Application
            Application app = r.packageInfo.makeApplication(false, mInstrumentation);
            //4. window
            Window window = null;
            if (r.mPendingRemoveWindow != null && r.mPreserveWindow) {
                window = r.mPendingRemoveWindow;
                ...
            }
            //5. 给Activity关联Context、创建所属于的Window对象并设置回调接口
            activity.attach(appContext, this, ...,window, ...);
            //6. 调用onCreate()-最终完成整个启动过程
            if (r.isPersistable()) {
                mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
            } else {
                mInstrumentation.callActivityOnCreate(activity, r.state);
            }
            return activity;
        }
        //Activity.java
        final void attach(Context context, ..., Window window, ...) {
            //1. 创建PhoneWindow
            mWindow = new PhoneWindow(this, window, activityConfigCallback);
            /**======================================================= * 2. `Activity`实现了`window`的`callback接口` * -外界状态改变时会回调Activity的方法: * -dispatchTouchEvent(处理屏幕点击事件) * -onAttachedToWindow(window被关联到WindowManager时调用) * -... *=========================================================*/
            mWindow.setWindowControllerCallback(this);
            mWindow.setCallback(this);
            mWindow.setOnWindowDismissedCallback(this);
            ...
            //3. 建立Window和WindowManager的联系
            mWindow.setWindowManager((WindowManager)context.getSystemService(Context.WINDOW_SERVICE), ...);
            if (mParent != null) {
                mWindow.setContainer(mParent.getWindow());
            }
            mWindowManager = mWindow.getWindowManager();
            mCurrentConfig = config;
            ...
        }
        //Window.java内部接口:
        public interface Callback { 
            //1. 事件分发机制源头
            public boolean dispatchTouchEvent(MotionEvent event);
            public boolean dispatchKeyEvent(KeyEvent event);
            public void onAttachedToWindow();
            public void onDetachedFromWindow();
            ......
        }

13、\* 老版`Window`对象的创建是通过`PolicyManager`的`makeNewWindow`方法实现:

> 1.  `PolicyManager`是一个策略类
> 2.  Activity的`Window`就是通过`PolicyManager`的一个工厂方法创建
> 3.  `PolicyManager`实现的工厂方法全部在策略接口`IPolicy`中声明
> 4.  `PolicyManager`的实现类是`Policy`类

//Window的实现类就是`PhoneWindow`
    public Window makeNewWindow(Context context){
      return new PhoneWindow(context);
    }

14、Activity的视图附加到Window的流程分析(setContentView)

//Activity.java
    public void setContentView(View view) {
        //通过PhoneWindow的setContentView
        getWindow().setContentView(view);
        initWindowDecorActionBar();
    }
    //PhoneWindow.java
    public void setContentView(int layoutResID) {
        //1. 创建DecorView
        if (mContentParent == null) {
            installDecor();
        }
        //2. 将Activity视图添加到mContentParent中(android.R.id.content)
        mLayoutInflater.inflate(layoutResID, mContentParent);
        /**======================================== * 3. 回调Activity的onContentChanged()方法 * -用于通知Activity视图发生改变 * -onContentChanged()是空实现可以自定义处理 *========================================*/
        final Callback cb = getCallback();
        if (cb != null && !isDestroyed()) {
            cb.onContentChanged();
        }
        ...
    }
    //PhoneWindow.java
    private void installDecor() {
        mForceDecorInstall = false;
        //1. DecorView不存在, 则创建
        if (mDecor == null) {
            mDecor = generateDecor(-1);
            ...
        } else {
            //2. DecorView存在，则与PhoneWindow关联
            mDecor.setWindow(this);
        }
        //3. 加载具体布局文件，到DecorView中
        if (mContentParent == null) {
            mContentParent = generateLayout(mDecor);
            ...
        }
    }
    /**============================================================= * `DecorView`的真正显示过程 * -通过onCreate()仅仅是将`Activity`的布局添加到`DecorView` * -`DecorView`添加到`Window`中后才能真正显示出来 * -`DecorView`是在主线程的handleResumeActivity()中添加到Window并显示 * //ActivityThread.java *=============================================================*/
    final void handleResumeActivity(IBinder token, ...) {
        //1. onResume()
        r = performResumeActivity(token, clearHide, reason);
        //2. 完成`DecorView`的添加和显示两个过程
        r.activity.makeVisible();
        ...
    }
    //Activity.java
    void makeVisible() {
        //1. 将`DecorView`添加到`Window`中(通过WindowManager)
        if (!mWindowAdded) {
            ViewManager wm = getWindowManager();
            wm.addView(mDecor, getWindow().getAttributes());
            mWindowAdded = true;
        }
        //2. 将DecorView显示出来
        mDecor.setVisibility(View.VISIBLE);
    }

## Dialog ##

15、Dialog的Window创建过程详解  
Dialog的使用:

AlertDialog alertDialog = new AlertDialog.Builder(this).setTitle("AlerDialog!").create();
    alertDialog.show();

Dialog的流程源码:

//Dialog.java: 显示Dialog
    public void show() {
        if (mShowing) {
            if (mDecor != null) {
                //1. 如果对应DecorView已经存在，直接显示
                mDecor.setVisibility(View.VISIBLE);
            }
            return;
        }
        //2. 获取DecorView
        mDecor = mWindow.getDecorView();
        //3. 通过WM的addView将Dialog进行显示
        WindowManager.LayoutParams l = mWindow.getAttributes();
        mWindowManager.addView(mDecor, l);
        ...
    }

16、Dialog的销毁流程分析

//Dialog.java
    public void dismiss() {
        //1. 线程安全，最终都在主线程移除该Dialog
        if (Looper.myLooper() == mHandler.getLooper()) {
            dismissDialog();
        } else {
            mHandler.post(mDismissAction);
        }
    }
    //Dialog.java
    void dismissDialog() {
        //1. 移除Window
        mWindowManager.removeViewImmediate(mDecor);
        ...
    }
    //WindowManagerImpl.java
    public void removeViewImmediate(View view) {
        mGlobal.removeView(view, true);
    }

17、 Dialog的注意点

> 1.  `Dialog`必须采用`Activity`的`Context`，因为需要有应用`token`(`Application`的`Context`没有应用token)
> 2.  也可以将`Dialog`的`Window`通过`type`设置为系统Window就不再需要token。

alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);

完整代码

//权限判断
    if (Build.VERSION.SDK_INT >= 23) {
        if (!Settings.canDrawOverlays(this)) {
            Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivityForResult(intent, 1);
        } else {
            //TODO 做你需要的事情
            alertDialog = new AlertDialog.Builder(getApplicationContext()).setTitle("AlerDialog!").create();
            alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
            alertDialog.show();
        }
    }

//AndroidManifest.xml-没有系统权限会导致报错
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

## Toast ##

18、Toast的内部机制介绍

> 1.  `Toast`也是基于`Window`来实现的
> 2.  `Toast`具有定时取消功能，系统采用`Handler`实现
> 3.  `Toast`内部有两类IPC过程：1-Toast访问NotificationManagerService；2-NotificationManagerService回调`Toast`的`TN`接口

19、Toast的show()方法原理分析

/** * Toast.java中显示和隐藏都是IPC过程 */
    public void show() {
        if (mNextView == null) {
            throw new RuntimeException("setView must have been called");
        }
        //1. 获取NotificaitonMnagerService
        INotificationManager service = getService();
        String pkg = mContext.getOpPackageName();
        //2. TN是Binder类，NotificationManagerService处理Toast显示时，会跨进程回调TN中的方法
        //3. TN运行在Binder线程池中，需要通过Hanlder将其切换到(发送Toast请求的)线程中
        //4. 使用Hanlder意味着Toast无法在没有Looper的线程中弹出
        TN tn = mTN;
        tn.mNextView = mNextView;
        try {
            //5. NotificationManagerService进行toast
            service.enqueueToast(pkg, //当前应用包名
                    tn,
                    mDuration);
        } catch (RemoteException e) {
            // Empty
        }
    }
    
    //NotificationManagerService
    public void enqueueToast(String pkg, ITransientNotification callback, int duration)
    {
        ...参数合法性判断...
        ...省略...
        synchronized (mToastQueue) {
            .......
            try {
                //1. 将Toast请求封装为`ToastRecord`
                ToastRecord record;
                int index = indexOfToastLocked(pkg, callback);
                //2. 如果ToastRecord已经在队列中(mToastQueue)，则直接更新
                if (index >= 0) {
                    record = mToastQueue.get(index);
                    record.update(duration);
                } else {
                    /**================================================================= *3. 限制非系统应用，队列最多能存50个(MAX_PACKAGE_NOTIFICATIONS)。 * 防止DOS(Denail of Service)攻击： * 如果一个应用大量连续弹出Toast，会导致其他应用没有机会弹出Toast *===============================================================*/
                    if (!isSystemToast) {
                        int count = 0;
                        final int N = mToastQueue.size();
                        for (int i=0; i<N; i++) {
                            final ToastRecord r = mToastQueue.get(i);
                            if (r.pkg.equals(pkg)) { //同一个包
                                count++;
                                if (count >= MAX_PACKAGE_NOTIFICATIONS) {
                                    Slog.e(TAG, "Package has already posted " + count
                                            + " toasts. Not showing more. Package=" + pkg);
                                    return;
                                }
                            }
                        }
                    }
                    //4. 将Toast存放到队列中
                    record = new ToastRecord(callingPid, pkg, callback, duration);
                    mToastQueue.add(record);
                    ......
                }
                /**=========================================================== * 5. 用于显示当前Toast * Toast显示由ToastRecord的callback(Toast的TN对象的远程Binder)完成 * 通过CallBack调用了TN中的方法，该方法运行在Toast请求方的Binder线程池中 *===========================================================*/
                //5. 用于显示当前Toast。
                if (index == 0) {
                    showNextToastLocked(); //Toast显示由ToastRecord的callback(Toast的TN对象的远程Binder)完成
                }
            } finally {
                Binder.restoreCallingIdentity(callingId);
            }
        }
    }
    
    //NotificationManagerService.java
    void showNextToastLocked() {
        ToastRecord record = mToastQueue.get(0);
        while (record != null) {
             ...省略...
            try {
                //1. 跨进程调用Toast中TN内部的show()方法进行展示
                record.callback.show();
                /**=========================================================== * 2. 会发送一个延时消息(取决于Toast的时长)。 * 1-Message最终会由NotificationMaService中的WorkerHandler处理 * 2-调用handleTimeout->cancelToastLocked->`record.callback.hide(); * 3-最终调用TN中的hide方法并且将ToastRecord从队列中移除 *===========================================================*/
                scheduleTimeoutLocked(record);
                return;
            } catch (RemoteException e) {
                ...省略...
            }
        }
    }

20、Toast的cancel()方法原理分析

> 1.  内部调用`NotificationManagerService`的cancelToast方法()
> 2.  cancelToast方法()->cancelToastLocked()->record.callback.hide();
> 3.  record.callback.hide()通过IPC调用TN中的hide方法
> 4.  最后将ToastRecord移除队列

//Toast.java
    public void cancel() {
        mTN.hide();
    
        try {
            getService().cancelToast(mContext.getPackageName(), mTN);
        } catch (RemoteException e) {
            // Empty
        }
    }

21、Toast的TN(Binder)内部机制

//Toast.java TN
    private static class TN extends ITransientNotification.Stub { 
        ...省略...
        WindowManager mWM;
        TN() { ...省略... }
        //1. 开启了mShow的Runnable
        public void show() {
            mHandler.post(mShow);
        }
        //2. 开启了mHide的Runnable
        public void hide() {
            if (localLOGV) Log.v(TAG, "HIDE: " + this);
            mHandler.post(mHide);
        }
        //3. 调用handleShow()进行显示
        final Runnable mShow = new Runnable() {
            public void run() {
                handleShow();
            }
        };
        //4. 调用handleHide()进行显示
        final Runnable mHide = new Runnable() {
            public void run() {
                handleHide();
                mNextView = null;
            }
        };
        //5. 真正完成显示功能
        public void handleShow() {
            ......
            //7. 将Toast视图添加到Window中
            mWM = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
            ......
            mWM.addView(mView, mParams);
            ......
        }
        //6. 真正完成隐藏功能
        public void handleHide() {
            if (mView != null) {
                //8. 将Toast视图从Window中移除
                if (mView.getParent() != null) {
                    mWM.removeView(mView);
                }
                mView = null;
            }
        }
        private void trySendAccessibilityEvent() {
            ......
        }
    }

## Window源码流程图 ##

22、WindowManager的addView工作流程:

Created with Raphaël 2.1.2WindowManagerServiceWindowManagerServiceSessionSessionWindowManagerWindowManagerWindowManagerGlobalWindowManagerGlobalViewRootImplViewRootImpl1.WM本身为接口 继承自ViewManager2.实现类: WindowManagerImpl3.mGlobal.addView()4.(3)new ViewRootImpl()5.(3)将ViewRootImpl View 布局参数 添加到列表中6.(3)root.setView()7.(6)requestLayout()8.(7)scheduleTraversals() \-绘制三大流程的入口9.(6)mWindowSession.addToDisplay(mWindow, ...)【IPC】10.mService. addWindow(...);

23、Window的removeView()流程分析:

Created with Raphaël 2.1.2WindowManagerGlobalWindowManagerGlobalViewRootImplViewRootImplWindowManagerServiceWindowManagerService1. 查询View的索引2. removeViewLocked()3. root.die()4. 将View添加到 等待删除列表中5. 同步删除: doDie()6. 异步删除: mHandler. sendEmptyMessage(MSG\_DIE)7.(5)dispatchDetachedFromWindow()8.(5)WindowManagerGlobal. doRemoveView(this)9.(7)mView. dispatchDetachedFromWindow()【IPC】10.(7)mWindowSession. remove(mWindow)11.removeWindow()

24、Activity从创建到显示的工作流程:

Created with Raphaël 2.1.2ActivityThreadActivityThreadActivityActivityPhoneWindowPhoneWindow1. handleLaunchActivity()2. performLaunchActivity()3.(2) 创建Context4.(2) 创建Activity5.(2) 创建Application6.(2) activity.attach()7.(2) mInstrumentation. callActivityOnCreate()8.(6) new PhoneWindow()9.(6) 给Window设置 Activity的回调： dispatchTouchEvent...10.(6) mWindow. setWindowManager()11.(7) onCreate()12. setContentView()13. getWindow(). setContentView(view)14. installDecor()15. mLayoutInflater. inflate(layoutResID, mContentParent)16. cb.onContentChanged()17.(14) generateDecor(-1)18.(14) generateLayout(mDecor)19. handleResumeActivity()20(19) performResumeActivity()21(19) activity.makeVisible()22.wm.addView(mDecor...)23.mDecor.setVisibility()

> 1.  建立Window和WindowManager联系：  
>     `mWindow.setWindowManager((WindowManager)context.getSystemService(Context.WINDOW_SERVICE), ...);`

[http_blog.csdn.net_feather_wch_article_details_79186967]: http://blog.csdn.net/feather_wch/article/details/79186967
[http_blog.csdn.net_feather_wch_article_details_79185045]: http://blog.csdn.net/feather_wch/article/details/79185045