WMS启动流程梳理（基于AndroidU）

WMS也是由SystemServer启动的
Q:\MTK_U\t-alps-mp-u0.mp1.rc-phone-Vx.xx\frameworks\base\services\java\com\android\server\SystemServer.java
    private void startOtherServices(@NonNull TimingsTraceAndSlog t) {
        t.traceBegin("startOtherServices");
        .......
        WindowManagerService wm = null;
        
        ......
        t.traceBegin("StartWindowManagerService");
        //在启动WMS之前需要先启动Sensor service
        mSystemServiceManager.startBootPhase(t, SystemService.PHASE_WAIT_FOR_SENSOR_SERVICE);
       //传入inputmanager ATMS 对象
       //创建一个PhoneWindowManager 对象
       //这里的PhoneWindowManager对象实际上是WindowManagerPolicy 
       wm = WindowManagerService.main(context, inputManager, !mFirstBoot,
                    new PhoneWindowManager(), mActivityManagerService.mActivityTaskManager);
         //把WMS对象加入到ServiceManager的监控队列之中         
            ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
                    DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);

            t.traceBegin("SetWindowManagerService");
            //把WMS 对象给到AMS
            mActivityManagerService.setWindowManager(wm);
            t.traceEnd();
 
            //调用WMS的onInitReady 初始化方法
            t.traceBegin("WindowManagerServiceOnInitReady");
            wm.onInitReady();
            t.traceEnd();
            
            .......
        t.traceBegin("MakeDisplayReady");
        try {
            wm.displayReady();
        } catch (Throwable e) {
            reportWtf("making display ready", e);
        }
        t.traceEnd();
        .......
        
        
        t.traceBegin("MakeWindowManagerServiceReady");
        try {
            wm.systemReady();
        } catch (Throwable e) {
            reportWtf("making Window Manager Service ready", e);
        }
        t.traceEnd();
        
        .......
        //更新下Configuration
        final Configuration config = wm.computeNewConfiguration(DEFAULT_DISPLAY);
        DisplayMetrics metrics = new DisplayMetrics();
        context.getDisplay().getMetrics(metrics);
        context.getResources().updateConfiguration(config, metrics);

systemserver 中执行了WMS的以下方法：

main

onInitReady

displayReady

systemReady

computeNewConfiguration

main

Q:\MTK_U\t-alps-mp-u0.mp1.rc-phone-Vx.xx\frameworks\base\services\core\java\com\android\server\wm\WindowManagerService.java
public static WindowManagerService main(final Context context, final InputManagerService im,
            final boolean showBootMsgs, WindowManagerPolicy policy,
            ActivityTaskManagerService atm) {
        return main(context, im, showBootMsgs, policy, atm, new DisplayWindowSettingsProvider(),
                SurfaceControl.Transaction::new, SurfaceControl.Builder::new);
    }
       public static WindowManagerService main(final Context context, final InputManagerService im,
            final boolean showBootMsgs, WindowManagerPolicy policy, ActivityTaskManagerService atm,
            DisplayWindowSettingsProvider displayWindowSettingsProvider,
            Supplier<SurfaceControl.Transaction> transactionFactory,
            Function<SurfaceSession, SurfaceControl.Builder> surfaceControlFactory) {
        final WindowManagerService[] wms = new WindowManagerService[1];
        DisplayThread.getHandler().runWithScissors(() ->
                wms[0] = new WindowManagerService(context, im, showBootMsgs, policy, atm,
                        displayWindowSettingsProvider, transactionFactory,
                        surfaceControlFactory), 0);
        return wms[0];
    }

main方法主要做两件事情：

1.调用WMS的构造方法，创建WMS对象并返回；

2.调用DisplayThread的getHandler对象，并将WMS对象传递给DisplayThread；

WMS构造方法

    private WindowManagerService(Context context, InputManagerService inputManager,
            boolean showBootMsgs, WindowManagerPolicy policy, ActivityTaskManagerService atm,
            DisplayWindowSettingsProvider displayWindowSettingsProvider,
            Supplier<SurfaceControl.Transaction> transactionFactory,
            Function<SurfaceSession, SurfaceControl.Builder> surfaceControlFactory) {
        installLock(this, INDEX_WINDOW);
        mGlobalLock = atm.getGlobalLock();
      
      //拿到AMS context进行赋值
        mAtmService = atm;
        mContext = context;
      ........
       //拿到InputManager对象
      mInputManager = inputManager; 
      ........
      //surface相关
        mSurfaceControlFactory = surfaceControlFactory;
        mTransactionFactory = transactionFactory;
        mTransaction = mTransactionFactory.get();
     .......
        //创建 WindowAnimator 对象 窗口动画
        mAnimator = new WindowAnimator(this);
        //创建RootWindowContainer 对象 根窗口容器
        mRoot = new RootWindowContainer(this);
     ........
       //拿到DisplayerManagerservice
       mDisplayManager = (DisplayManager)context.getSystemService(Context.DISPLAY_SERVICE);
      
      // AMS相关
        mActivityManager = ActivityManager.getService();
        mAmInternal = LocalServices.getService(ActivityManagerInternal.class);
        mUmInternal = LocalServices.getService(UserManagerInternal.class);
     ........
}

onInitReady

    public void onInitReady() {
      //PhoneWindowManager相关
        initPolicy();
        
      //把WMS加入到WatchDog的监控中
        Watchdog.getInstance().addMonitor(this);
      //创建系统水印
        createWatermark();
        showEmulatorDisplayOverlayIfNeeded();

displayReady

    public void displayReady() {
        synchronized (mGlobalLock) {
            if (mMaxUiWidth > 0) {
                mRoot.forAllDisplays(displayContent -> displayContent.setMaxUiWidth(mMaxUiWidth));
            }
            applyForcedPropertiesForDefaultDisplay();
            mAnimator.ready();
            mDisplayReady = true;
          //根据DisplayContent重新配置显示器的大小
            mRoot.forAllDisplays(DisplayContent::reconfigureDisplayLocked);
          //判断是否是触摸屏
            mIsTouchDevice = mContext.getPackageManager().hasSystemFeature(
                    PackageManager.FEATURE_TOUCHSCREEN);
            mIsFakeTouchDevice = mContext.getPackageManager().hasSystemFeature(
                    PackageManager.FEATURE_FAKETOUCH);
        }
      //AMS更新
        mAtmService.updateConfiguration(null /* request to compute config */);
    }

systemReady

    public void systemReady() {
        mSystemReady = true;
      //调用PhoneWindowManager的systemReady
        mPolicy.systemReady();
        mRoot.forAllDisplayPolicies(DisplayPolicy::systemReady);
        mSnapshotController.systemReady();
        mHasWideColorGamutSupport = queryWideColorGamutSupport();
        mHasHdrSupport = queryHdrSupport();
      //加载系统设置信息
        UiThread.getHandler().post(mSettingsObserver::loadSettings);
        IVrManager vrManager = IVrManager.Stub.asInterface(
                ServiceManager.getService(Context.VR_SERVICE));
      //VR相关
        if (vrManager != null) {
            try {
                final boolean vrModeEnabled = vrManager.getVrModeState();
                synchronized (mGlobalLock) {
                    vrManager.registerListener(mVrStateCallbacks);
                    if (vrModeEnabled) {
                        mVrModeEnabled = vrModeEnabled;
                        mVrStateCallbacks.onVrStateChanged(vrModeEnabled);
                    }
                }
            } catch (RemoteException e) {
                // Ignore, we cannot do anything if we failed to register VR mode listener
            }
        }
    

DisplayThread

Q:\MTK_U\t-alps-mp-u0.mp1.rc-phone-Vx.xx\frameworks\base\services\core\java\com\android\server\DisplayThread.java
public final class DisplayThread extends ServiceThread {
    private static DisplayThread sInstance;
    private static Handler sHandler;

    private DisplayThread() {
        // DisplayThread runs important stuff, but these are not as important as things running in
        // AnimationThread. Thus, set the priority to one lower.
        super("android.display", Process.THREAD_PRIORITY_DISPLAY + 1, false /*allowIo*/);
    }

DisplayThread继承自ServiceThread

trace中看到的android.display 线程就是DisplayThread,该线程的优先级是Process.THREAD_PRIORITY_DISPLAY + 1（-3）

Q:\MTK_U\t-alps-mp-u0.mp1.rc-phone-Vx.xx\frameworks\base\services\core\java\com\android\server\UiThread.java
public final class UiThread extends ServiceThread {
    private static final long SLOW_DISPATCH_THRESHOLD_MS = 100;
    private static final long SLOW_DELIVERY_THRESHOLD_MS = 200;
    private static UiThread sInstance;
    private static Handler sHandler;

    private UiThread() {
        super("android.ui", Process.THREAD_PRIORITY_FOREGROUND, false /*allowIo*/);
    }

    @Override
    public void run() {
        // Make sure UiThread is in the fg stune boost group
        Process.setThreadGroup(Process.myTid(), Process.THREAD_GROUP_TOP_APP);
        super.run();
    }