injectInputEvent 在Android上的调用过程

Android 2.3
frameworks/base/core/java/android/app/Instrumentation.java:   
public void sendPointerSync(MotionEvent event){
IWindowManager.Stub.asInterface(ServiceManager.getService("window"))).injectPointerEvent(event, true)
frameworks/base/services/java/com/android/server/WindowManagerService.java:  
final InputManager mInputManager;
public boolean injectPointerEvent(MotionEvent ev, boolean sync)
final int result = mInputManager.injectInputEvent(newEvent, pid, uid,
                sync ? InputManager.INPUT_EVENT_INJECTION_SYNC_WAIT_FOR_FINISH
                        : InputManager.INPUT_EVENT_INJECTION_SYNC_WAIT_FOR_RESULT,
                INJECTION_TIMEOUT_MILLIS);
frameworks/base/services/java/com/android/server/InputManager.java:    
 public int injectInputEvent(InputEvent event, int injectorPid, int injectorUid, int syncMode, int timeoutMillis) {
        if (event == null) {
            throw new IllegalArgumentException("event must not be null");
        }
        if (injectorPid < 0 || injectorUid < 0) {
            throw new IllegalArgumentException("injectorPid and injectorUid must not be negative.");
        }
        if (timeoutMillis <= 0) {
            throw new IllegalArgumentException("timeoutMillis must be positive");
        }

        return nativeInjectInputEvent(event, injectorPid, injectorUid, syncMode, timeoutMillis);
    }

frameworks/base/services/jni/com_android_server_InputManager.cpp:static jint android_server_InputManager_nativeInjectInputEvent(JNIEnv* env, jclass clazz,
frameworks/base/services/jni/com_android_server_InputManager.cpp:    { "nativeInjectInputEvent", "(Landroid/view/InputEvent;IIII)I",
return gNativeInputManager->getInputManager()->getDispatcher()->injectInputEvent(& motionEvent, injectorPid, injectorUid, syncMode, timeoutMillis);
mInputManager = new InputManager(eventHub, this, this);

Android 4.0:

\frameworks\base\core\java\android\app\Instrumentation.java
public void sendPointerSync(MotionEvent event) {
        validateNotAppThread();
        if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) == 0) {
            event.setSource(InputDevice.SOURCE_TOUCHSCREEN);
        }
        InputManager.getInstance().injectInputEvent(event,
                InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_FINISH);
    }
\frameworks\base\core\java\android\hardware\input\InputManager.java

private final IInputManager mIm;

 public boolean injectInputEvent(InputEvent event, int mode) {
        if (event == null) {
            throw new IllegalArgumentException("event must not be null");
        }
        if (mode != INJECT_INPUT_EVENT_MODE_ASYNC
                && mode != INJECT_INPUT_EVENT_MODE_WAIT_FOR_FINISH
                && mode != INJECT_INPUT_EVENT_MODE_WAIT_FOR_RESULT) {
            throw new IllegalArgumentException("mode is invalid");
        }
        try {
            return mIm.injectInputEvent(event, mode);
        } catch (RemoteException ex) {
            return false;
        }
    }
\frameworks\base\services\java\com\android\server\input\InputManagerService.java
 public boolean injectInputEvent(InputEvent event, int mode) {
        if (event == null) {
            throw new IllegalArgumentException("event must not be null");
        }
        if (mode != InputManager.INJECT_INPUT_EVENT_MODE_ASYNC
                && mode != InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_FINISH
                && mode != InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_RESULT) {
            throw new IllegalArgumentException("mode is invalid");
        }


        final int pid = Binder.getCallingPid();
        final int uid = Binder.getCallingUid();
        final long ident = Binder.clearCallingIdentity();
        final int result;
        try {
            result = nativeInjectInputEvent(mPtr, event, pid, uid, mode,
                    INJECTION_TIMEOUT_MILLIS, WindowManagerPolicy.FLAG_DISABLE_KEY_REPEAT);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
        switch (result) {
            case INPUT_EVENT_INJECTION_PERMISSION_DENIED:
                Slog.w(TAG, "Input event injection from pid " + pid + " permission denied.");
                throw new SecurityException(
                        "Injecting to another application requires INJECT_EVENTS permission");
            case INPUT_EVENT_INJECTION_SUCCEEDED:
                return true;
            case INPUT_EVENT_INJECTION_TIMED_OUT:
                Slog.w(TAG, "Input event injection from pid " + pid + " timed out.");
                return false;
            case INPUT_EVENT_INJECTION_FAILED:
            default:
                Slog.w(TAG, "Input event injection from pid " + pid + " failed.");
                return false;
        }
    }


Note：Inject event to Android system need system permission.