Android6.0 WMS（一） WMS和應用進程的關係

之前在分析Activity的時候有很多和WMS相關的，我們這裏再簡單總結下和WMS相關的那部分。

一、appToken在WMS中創建

在博客http://blog.csdn.net/kc58236582/article/details/52413871中在APPWindowToken創建過程這節中，我們分析到在AMS調用startActivityLocked的時候，會調用WMS的addAppToken來創建一個APPWindowToken。


    final void startActivityLocked(ActivityRecord r, boolean newTask,
            boolean doResume, boolean keepCurTransition, Bundle options) {
        TaskRecord rTask = r.task;
        final int taskId = rTask.taskId;
        // mLaunchTaskBehind tasks get placed at the back of the task stack.
        if (!r.mLaunchTaskBehind && (taskForIdLocked(taskId) == null || newTask)) {
            // Last activity in task had been removed or ActivityManagerService is reusing task.
            // Insert or replace.
            // Might not even be in.
            insertTaskAtTop(rTask, r);
            mWindowManager.moveTaskToTop(taskId);
        }
        TaskRecord task = null;
        if (!newTask) {
            // If starting in an existing task, find where that is...
            boolean startIt = true;
            for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
                task = mTaskHistory.get(taskNdx);
                if (task.getTopActivity() == null) {
                    // All activities in task are finishing.
                    continue;
                }
                if (task == r.task) {
                    // Here it is!  Now, if this is not yet visible to the
                    // user, then just add it without starting; it will
                    // get started when the user navigates back to it.
                    if (!startIt) {
                        if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to task "
                                + task, new RuntimeException("here").fillInStackTrace());
                        task.addActivityToTop(r);
                        r.putInHistory();
                        mWindowManager.addAppToken(task.mActivities.indexOf(r), r.appToken,
                                r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
                                (r.info.flags & ActivityInfo.FLAG_SHOW_FOR_ALL_USERS) != 0,
                                r.userId, r.info.configChanges, task.voiceSession != null,
                                r.mLaunchTaskBehind);

我們再來看看WMS的addAppToken函數，在WMS中創建了APPWindowToken然後保存在mTokenMap中。


    public void addAppToken(int addPos, IApplicationToken token, int taskId, int stackId,
            int requestedOrientation, boolean fullscreen, boolean showForAllUsers, int userId,
            int configChanges, boolean voiceInteraction, boolean launchTaskBehind) {
        ......
        synchronized(mWindowMap) {
            AppWindowToken atoken = findAppWindowToken(token.asBinder());//如果已經有了直接退出
            if (atoken != null) {
                Slog.w(TAG, "Attempted to add existing app token: " + token);
                return;
            }
            atoken = new AppWindowToken(this, token, voiceInteraction);//新建一個APPWindowToken
            atoken.inputDispatchingTimeoutNanos = inputDispatchingTimeoutNanos;
            atoken.appFullscreen = fullscreen;
            atoken.showForAllUsers = showForAllUsers;
            atoken.requestedOrientation = requestedOrientation;
            atoken.layoutConfigChanges = (configChanges &
                    (ActivityInfo.CONFIG_SCREEN_SIZE | ActivityInfo.CONFIG_ORIENTATION)) != 0;
            atoken.mLaunchTaskBehind = launchTaskBehind;
            if (DEBUG_TOKEN_MOVEMENT || DEBUG_ADD_REMOVE) Slog.v(TAG, "addAppToken: " + atoken
                    + " to stack=" + stackId + " task=" + taskId + " at " + addPos);
 
            Task task = mTaskIdToTask.get(taskId);
            if (task == null) {
                task = createTaskLocked(taskId, stackId, userId, atoken);
            }
            task.addAppToken(addPos, atoken);
 
            mTokenMap.put(token.asBinder(), atoken);//保存在mTokenMap中 token爲key（Activity的binder對象）
 
            // Application tokens start out hidden.
            atoken.hidden = true;
            atoken.hiddenRequested = true;
        }
    }

再來看看AppWindowToken的構造函數，它是WindowToken的子類，再調用父類構造函數的時候說明了自己是TYPE_APPLICATION類型的。參數_token指向的是一個ActivityRecord對象的IBinder接口，因此，AppWindowToken類的成員變量appToken描述的就是一個ActivityRecord對象。


    AppWindowToken(WindowManagerService _service, IApplicationToken _token,
            boolean _voiceInteraction) {
        super(_service, _token.asBinder(),
                WindowManager.LayoutParams.TYPE_APPLICATION, true);
        appWindowToken = this;
        appToken = _token;
        voiceInteraction = _voiceInteraction;
        mInputApplicationHandle = new InputApplicationHandle(this);
        mAnimator = service.mAnimator;
        mAppAnimator = new AppWindowAnimator(this);
    }

二、Activity的attach函數

首先在博客http://blog.csdn.net/kc58236582/article/details/52397657中主要分析了Activity的創建初始化。

handleLaunchActivity函數先調用performLaunchActivity函數，再調用handleResumeActivity函數。

在performLaunchActivity函數先新建Activity，然後調用其attach函數，最後調用了Activity的onCreate函數。

在Activity的attach函數中，主要代碼如下：


 ......
        mWindow = new PhoneWindow(this);//新建PhoneWindow對象
        mWindow.setCallback(this);//這window中設置回調，在按鍵事件分發的時候中用到。如果有這個回調，就調用Activity的dispatchKeyEvent
        mWindow.setOnWindowDismissedCallback(this);
   ......
   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();

三、創建ViewRootImpl、DecorView

我們繼續分析，在http://blog.csdn.net/kc58236582/article/details/52411791博客，我們分析到了ViewRootImpl和DecorView的創建。

一般在Activity的onCreate函數中會調用setContentView。而在setContentView會創建DecorView對象。

下面我們再從ActivityThread的handleResumeActivity函數看，先調用了performResumeActivity函數來查找這個Activity，後面主要調用了WindowManager的addView函數。


    final void handleResumeActivity(IBinder token,
            boolean clearHide, boolean isForward, boolean reallyResume) {
        // 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
        ActivityClientRecord r = performResumeActivity(token, clearHide);
 
        if (r != null) {
            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,
            // and this guy didn't finish itself or start another activity,
            // then go ahead and add the window.
            boolean willBeVisible = !a.mStartedActivity;
            if (!willBeVisible) {
                try {
                    willBeVisible = ActivityManagerNative.getDefault().willActivityBeVisible(
                            a.getActivityToken());
                } catch (RemoteException e) {
                }
            }
            if (r.window == null && !a.mFinished && willBeVisible) {
                r.window = r.activity.getWindow();
                View decor = r.window.getDecorView();
                decor.setVisibility(View.INVISIBLE);
                ViewManager wm = a.getWindowManager();
                WindowManager.LayoutParams l = r.window.getAttributes();
                a.mDecor = decor;
                l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
                l.softInputMode |= forwardBit;
                if (a.mVisibleFromClient) {
                    a.mWindowAdded = true;
                    wm.addView(decor, l);
                }

我們來看WindowManagerImpl的addView函數，其實就是調用了WindowManagerGlobal的addView函數


    @Override
    public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
        applyDefaultToken(params);
        mGlobal.addView(view, params, mDisplay, mParentWindow);
    }

之前也分析過WindowManagerGlobal，它有3個重要的成員變量：


    private final ArrayList<View> mViews = new ArrayList<View>();//所有的DecorView對象
    private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>();//所有的ViewRootImpl對象
    private final ArrayList<WindowManager.LayoutParams> mParams =//所有頂層View的layout參數
            new ArrayList<WindowManager.LayoutParams>();

們再來看WindowManagerGlobal的addView函數，這個函數先是查找是否已經在WindowManagerGlobal中已經有這個view，如果有的話就調用其ViewRootImpl的doDie函數中主要是調用WindowManagerGlobal函數去除這個ViewRootImpl對象，在這個主要是創建了ViewRootImpl，並且把DecorView，RootViewRootImpl，layout參數都保存起來了。然後調用了ViewRootImpl的setView函數。


    public void addView(View view, ViewGroup.LayoutParams params,
            Display display, Window parentWindow) {
        ......
        int index = findViewLocked(view, false);//查找是否有該view，獲取其index
            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();//調用ViewRootImpl的doDie函數
                } else {
                    throw new IllegalStateException("View " + view
                            + " has already been added to the window manager.");
                }
                // The previous removeView() had not completed executing. Now it has.
            }
        ......
 
            root = new ViewRootImpl(view.getContext(), display);//新建ViewRootImpl對象
 
            view.setLayoutParams(wparams);
 
            mViews.add(view);//成員變量增加
            mRoots.add(root);
            mParams.add(wparams);
        }
 
        // do this last because it fires off messages to start doing things
        try {
            root.setView(view, wparams, panelParentView);//調用ViewRootImpl的setView函數
        } catch (RuntimeException e) {
            // BadTokenException or InvalidDisplayException, clean up.
            synchronized (mLock) {
                final int index = findViewLocked(view, false);
                if (index >= 0) {
                    removeViewLocked(index, true);
                }
            }
            throw e;
        }
    }

四、ViewRootImpl的setView函數

上面在創建完ViewRootImpl之後會調用其setView函數，setView函數主要可以分成兩個部分。

4.1 requestLayout函數

在setView中先會調用requestLayout函數，這個函數在http://blog.csdn.net/kc58236582/article/details/52421683博客中有詳細分析，主要調用了WMS的relayoutWindow函數，然後通過SurfaceFlinger來創建一個Surface

4.2 addToDisplay

另一部分就是如下代碼，最終會調用WMS的addWindow函數，增加窗口。在http://blog.csdn.net/kc58236582/article/details/52413871博客中WindowState的創建過程那節中有詳細分析。


                    res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
                            getHostVisibility(), mDisplay.getDisplayId(),
                            mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
                            mAttachInfo.mOutsets, mInputChannel);

Android6.0 WMS（一） WMS和應用進程的關係

一、appToken在WMS中創建

二、Activity的attach函數

三、創建ViewRootImpl、DecorView

四、ViewRootImpl的setView函數

4.1 requestLayout函數

4.2 addToDisplay

Android6.0 旋轉屏幕（二）旋轉設備

Android6.0 WMS（五） WMS計算Activity窗口大小的過程分析（一）應用進程

Android6.0 WMS（四） WMS中常用變量分析

Android6.0 WMS（二） WMS創建窗口與創建Surface的關係

Android6.0 WMS（一） WMS和應用進程的關係

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