Android InputMonitor

InputMonitor是InputManagerService和WMS之间的纽带，SystemServer.java中 startOtherServices()方法下进行初始化：

            inputManager = new InputManagerService(context);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);

            traceBeginAndSlog("StartWindowManagerService");
            wm = WindowManagerService.main(context, inputManager,
                    mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
                    !mFirstBoot, mOnlyCore);
            ServiceManager.addService(Context.WINDOW_SERVICE, wm);
            ServiceManager.addService(Context.INPUT_SERVICE, inputManager);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);

            traceBeginAndSlog("StartVrManagerService");
            mSystemServiceManager.startService(VrManagerService.class);
            Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);

            mActivityManagerService.setWindowManager(wm);

            inputManager.setWindowManagerCallbacks(wm.getInputMonitor());//互相关联
            inputManager.start();

其中 wm.getInputMonitor()方法在WindowManagerService.java中如下：

 public InputMonitor getInputMonitor() {
        return mInputMonitor;
    }

    final InputMonitor mInputMonitor = new InputMonitor(this);

当IMS接收到相应输入事件后，会通过mWindowManagerCallbacks 来调用mInputMonitor对象方法：

return  mWindowManagerCallbacks.notifyConfigurationChanged();
return  mWindowManagerCallbacks.notifyLidSwitchChanged(whenNanos, lidOpen);       

return  mWindowManagerCallbacks.notifyCameraLensCoverSwitchChanged(whenNanos, lensCovered);

return mWindowManagerCallbacks.notifyInputChannelBroken(inputWindowHandle);
return mWindowManagerCallbacks.notifyANR(
return mWindowManagerCallbacks.interceptKeyBeforeQueueing(event, policyFlags);
 return mWindowManagerCallbacks.interceptMotionBeforeQueueingNonInteractive(
 return mWindowManagerCallbacks.interceptKeyBeforeDispatching(focus, event, policyFlags);
 return mWindowManagerCallbacks.dispatchUnhandledKey(focus, event, policyFlags);
 return mWindowManagerCallbacks.getPointerLayer();