Android 4.0 用户输入子系统

1.Android 4.0 用户输入子系统代码模块
frameworks/base/services/java/com/android/server/SystemServer.java
frameworks/base/services/java/com/android/server/wm/WindowManagerService.java
frameworks/base/services/java/com/android/server/wm/InputManager.java
frameworks/base/services/jni/com_android_server_InputManager.cpp
frameworks/base/services/input/Android.mk
frameworks/base/services/input/EventHub.cpp
frameworks/base/services/input/EventHub.h
frameworks/base/services/input/InputApplication.cpp
frameworks/base/services/input/InputDispatcher.cpp
frameworks/base/services/input/InputListener.cpp
frameworks/base/services/input/InputDispatcher.h
frameworks/base/services/input/InputListener.h
frameworks/base/services/input/InputManager.cpp
frameworks/base/services/input/InputManager.h
frameworks/base/services/input/InputReader.cpp
frameworks/base/services/input/InputReader.h
frameworks/base/services/input/InputWindow.cpp
frameworks/base/services/input/InputWindow.h
frameworks/base/services/input/PointerController.cpp
frameworks/base/services/input/PointerController.h
frameworks/base/services/input/SpriteController.cpp

frameworks/base/services/input/SpriteController.h

2.Service and WindowManagerService

Source code:frameworks/base/services/java/com/android/server/SystemServer.java
    class ServerThread extends Thread {
          private static final String TAG = "SystemServer";

          /*。。。。。。。。。。处略过若干行。。。。。。。。。*/
                  Slog.i(TAG, "Window Manager");
                  wm = WindowManagerService.main(context, power,
                          factoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL,
                          !firstBoot);
                  ServiceManager.addService(Context.WINDOW_SERVICE, wm);

                  ActivityManagerService.self().setWindowManager(wm);

    }

功能描述：系统启动过程通过SystemServer添加WindowManagerService到服务列表

--WindowManagerService的构造方法

Source code:frameworks/base/services/java/com/android/server/wm/WindowManagerService.java
    private WindowManagerService(Context context, PowerManagerService pm,
                  boolean haveInputMethods, boolean showBootMsgs) {

              mInputManager = new InputManager(context, this);/*构造InputManager*/

              PolicyThread thr = new PolicyThread(mPolicy, this, context, pm);
              thr.start();
                    /*debug by Joyce*/
              synchronized (thr) {
                  while (!thr.mRunning) {
                      try {
                          thr.wait();
                      } catch (InterruptedException e) {
                      }
                  }
              }
              mInputManager.start();/*启动InputManager*/
          }

功能描述：1)初始化并构造一个InputManager实例mInputManager
                    2)开启InputManager(由InputManager本身start()方法实现)

--InputManager构造方法以及start()方法的实现

Source code:frameworks/base/services/java/com/android/server/wm/InputManager.java
    public InputManager(Context context, WindowManagerService windowManagerService) {
              this.mContext = context;
              this.mWindowManagerService = windowManagerService;
              this.mCallbacks = new Callbacks();
                    /*现在知道为何与WindowManagerService有关系了吧
                     *因为InputManager的各种需求
                        */
                    /*获取Looper循环队列?说实话我已经忘记了,只不过还记得那一副经典的图*/
              Looper looper = windowManagerService.mH.getLooper();
              Slog.i(TAG, "Initializing input manager");

              nativeInit(mContext, mCallbacks, looper.getQueue());/*初始化InputManager*/
          }
            /*debug by Joyce*/
          public void start() {
              Slog.i(TAG, "Hey Joyce Starting input manager");

              nativeStart();/*启动InputManager的本地实现*/

          }
    }

功能描述：1)调用JNI本地框架中的nativeInit方法来初始化InputManager
                    2)调用JNI本地框架中的nativeStart方法来开启InputManager

3.JNI本地框架的实现
--com_android_server_InputManager中给上层InputManager所提供的两个本地AP的实现

------------------>A部分

Source code:frameworks/base/services/jni/com_android_server_InputManager.cpp
    /*方法映射表*/
    static JNINativeMethod gInputManagerMethods[] = {
          /* name, signature, funcPtr */
          { "nativeInit", "(Landroid/content/Context;"
                  "Lcom/android/server/wm/InputManager$Callbacks;Landroid/os/MessageQueue;)V",
                  (void*) android_server_InputManager_nativeInit },
          { "nativeStart", "()V",
                  (void*) android_server_InputManager_nativeStart },
    }

    static void android_server_InputManager_nativeInit(JNIEnv* env, jclass clazz,
              jobject contextObj, jobject callbacksObj, jobject messageQueueObj) {
          if (gNativeInputManager == NULL) {/*首次调用肯定为NULL*/
              sp<Looper> looper = android_os_MessageQueue_getLooper(env, messageQueueObj);
              gNativeInputManager = new NativeInputManager(contextObj, callbacksObj, looper);
          } else {
              LOGE("Input manager already initialized.");
              jniThrowRuntimeException(env, "Input manager already initialized.");
          }
    }

--NativeInputManager本地类的构造函数
    NativeInputManager::NativeInputManager(jobject contextObj,
              jobject callbacksObj, const sp<Looper>& looper) :
              mLooper(looper) {
          JNIEnv* env = jniEnv();
            /*程序到这里就已经为我们创建一个inputdevice HAL 的实例了*/
          sp<EventHub> eventHub = new EventHub();/*creat the EventHub 一系列的memset*/
            /*并以eventHub为参数为我们创建了一个InputManager本地实例,注意这个InputManager
                是上层InputManager的本地实现定义在InputManager.cpp中
                */
          mInputManager = new InputManager(eventHub, this, this);
    }
--InputManager构造函数的实现
Source code：frameworks/base/services/input/InputManager.cpp
InputManager::InputManager(
        const sp<EventHubInterface>& eventHub,
        const sp<InputReaderPolicyInterface>& readerPolicy,
        const sp<InputDispatcherPolicyInterface>& dispatcherPolicy) {
    mDispatcher = new InputDispatcher(dispatcherPolicy);
    mReader = new InputReader(eventHub, readerPolicy, mDispatcher);
    initialize();
}

功能描述：1)创建NativeInputManager对象并保存成gNativeInputManager,该变量马上就会被用到
                    2)创建NativeInputManager对象的同时创建EventHub对象，并将创建的EventHub对象mEventHub作为参数传递给InputManager
                       的构造函数创建InputManager对象mInputManager
                    3)构建InputManager的同时会为我们构建InputDispatcher和InputReader对象
                    4)好了其实到这里就已经进入了本地C++框架层了,先到此打住,把下面这个JNI方法先分析一番

------------------>B部分

static void android_server_InputManager_nativeStart(JNIEnv* env, jclass clazz) {
      if (checkInputManagerUnitialized(env)) {
          return;
      }

      status_t result = gNativeInputManager->getInputManager()->start();
      if (result) {
          jniThrowRuntimeException(env, "Input manager could not be started.");
      }
}

功能描述：1)很简单直接调用上面初始化过程中创建的NativeInputManager对象mNativeInputManager去调用getInputManager()函数,该函数又刚好返回InputManager对象mInputManager了
                    2)再由mInputManager去调用它本身的start()方法来启动InputManager
                    3)从上面的这些方法可以得知在上层我们开启InputManager实质是开启了本地C++框架中的InputManager
4.C++Input框架的实现