Android5.0 输入系统（一）————InputManagerService服务及相关对象的创建与启动

frameworks\base\services\java\com\android\server\SystemServer.java

public static void main(String[] args) {
new SystemServer().run();
}

frameworks\base\services\java\com\android\server\SystemServer.java

private void run() {
......

try {
startBootstrapServices();
startCoreServices();
startOtherServices();
} catch (Throwable ex) {
Slog.e("System", "******************************************");
Slog.e("System", "************ Failure starting system services", ex);
throw ex;
}
......
}

frameworks\base\services\java\com\android\server\SystemServer.java

startOtherServices(){

......
/*Step1: 新建IMS*/
inputManager = new InputManagerService(context);

wm = WindowManagerService.main(context, inputManager,
mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
!mFirstBoot, mOnlyCore);
ServiceManager.addService(Context.WINDOW_SERVICE, wm);
/*Step2: 注册*/
ServiceManager.addService(Context.INPUT_SERVICE, inputManager);

mActivityManagerService.setWindowManager(wm);
/*Step3: 设置向WMS发起回调的callback对象*/
inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
/*Step4: 正式启动*/
inputManager.start();
......
}

Step1: 新建IMS

frameworks\base\services\core\java\com\android\server\input\InputManagerService.java

public InputManagerService(Context context) {
this.mContext = context;
this.mHandler = new InputManagerHandler(DisplayThread.get().getLooper());

mUseDevInputEventForAudioJack =
context.getResources().getBoolean(R.bool.config_useDevInputEventForAudioJack);
Slog.i(TAG, "Initializing input manager, mUseDevInputEventForAudioJack="
+ mUseDevInputEventForAudioJack);
/*每一个分为Java和Native两部分的对象在创建时都有一个nativeInput函数,
mPtr保存native层的InputMangerService*/
mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());

LocalServices.addService(InputManagerInternal.class, new LocalService());
}

frameworks\base\services\core\jni\com_android_server_input_InputManagerService.cpp

static jlong nativeInit(JNIEnv* env, jclass clazz,
jobject serviceObj, jobject contextObj, jobject messageQueueObj) {
/*java层转换为C++层*/
sp<MessageQueue> messageQueue = android_os_MessageQueue_getMessageQueue(env, messageQueueObj);
if (messageQueue == NULL) {
jniThrowRuntimeException(env, "MessageQueue is not initialized.");
return 0;
}

/*NativeInputManager是Native层组件与java层IMS进行通信的桥梁*/
NativeInputManager* im = new NativeInputManager(contextObj, serviceObj,
messageQueue->getLooper());
im->incStrong(0);
/*返回NativeInputManager对象的指针给Java层的IMS，IMS将其
*保存在mPtr成员变量中*/
return reinterpret_cast<jlong>(im);
}frameworks\base\services\core\jni\com_android_server_input_InputManagerService.cpp
NativeInputManager::NativeInputManager(jobject contextObj,
jobject serviceObj, const sp<Looper>& looper) :
mLooper(looper), mInteractive(true) {
JNIEnv* env = jniEnv();
......
/*创建一个EventHub*/
sp<EventHub> eventHub = new EventHub();
/*创建一个native层的InputManager*/
mInputManager = new InputManager(eventHub, this, this);
}frameworks\native\services\inputflinger\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);
/*初始化，即创建两个线程。*/
initialize();
}frameworks\native\services\inputflinger\InputDispatcher.cpp

InputDispatcher::InputDispatcher(const sp<InputDispatcherPolicyInterface>& policy) :
mPolicy(policy),
mPendingEvent(NULL), mAppSwitchSawKeyDown(false), mAppSwitchDueTime(LONG_LONG_MAX),
mNextUnblockedEvent(NULL),
mDispatchEnabled(false), mDispatchFrozen(false), mInputFilterEnabled(false),
mInputTargetWaitCause(INPUT_TARGET_WAIT_CAUSE_NONE) {
mLooper = new Looper(false);

mKeyRepeatState.lastKeyEntry = NULL;
/*配置相关*/
policy->getDispatcherConfiguration(&mConfig);
}

      注意InputDispatcher类和InputReader类的成员变量mPolicy的赋值都为为NativeInputManager对象，请看博文最后的类图。
frameworks\native\services\inputflinger\InputReader.cpp

InputReader::InputReader(const sp<EventHubInterface>& eventHub,
const sp<InputReaderPolicyInterface>& policy,
const sp<InputListenerInterface>& listener) :
mContext(this), mEventHub(eventHub), mPolicy(policy),
mGlobalMetaState(0), mGeneration(1),
mDisableVirtualKeysTimeout(LLONG_MIN), mNextTimeout(LLONG_MAX),
mConfigurationChangesToRefresh(0) {
mQueuedListener = new QueuedInputListener(listener);

{ // acquire lock
AutoMutex _l(mLock);

refreshConfigurationLocked(0);
updateGlobalMetaStateLocked();
} // release lock
}

      注意InputReader对象的构造函数的参数，第一个参数是前面创建的EventHub对象的引用，第二个参数是NativeInputManager对象的引用，第三个参数是InputDispatcher对象的引用。InputRead对象的构造函数创建一个队列监听器mQueuedListener，传入的参数是InputDispatcher对象的引用。

QueuedInputListener::QueuedInputListener(const sp<InputListenerInterface>& innerListener) :
mInnerListener(innerListener) {
}

      传入的参数是InputDispatcher对象的引用。
frameworks\native\services\inputflinger\InputManager.cpp

void InputManager::initialize() {
mReaderThread = new InputReaderThread(mReader);
mDispatcherThread = new InputDispatcherThread(mDispatcher);
}

Step2: 正式启动
frameworks\base\services\core\java\com\android\server\input\InputManagerService.java
public void start() {
Slog.i(TAG, "Starting input manager");
nativeStart(mPtr);

// Add ourself to the Watchdog monitors.
Watchdog.getInstance().addMonitor(this);

registerPointerSpeedSettingObserver();
registerShowTouchesSettingObserver();

mContext.registerReceiver(new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
updatePointerSpeedFromSettings();
updateShowTouchesFromSettings();
}
}, new IntentFilter(Intent.ACTION_USER_SWITCHED), null, mHandler);

updatePointerSpeedFromSettings();
updateShowTouchesFromSettings();
}frameworks\base\services\core\jni\com_android_server_input_InputManagerService.cpp

static void nativeStart(JNIEnv* env, jclass clazz, jlong ptr) {
NativeInputManager* im = reinterpret_cast<NativeInputManager*>(ptr);

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

      Java层传递过来的参数ptr实际上是Native层创建的NativeInputManager的指针，故可以转换。调用NativeInputManager对象的getInputManager()方法，得到InputManager对象，并调用其start()方法。
frameworks\native\services\inputflinger\InputManager.cpp
status_t InputManager::start() {
status_t result = mDispatcherThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY);
result = mReaderThread->run("InputReader", PRIORITY_URGENT_DISPLAY);
return OK;
}



      这幅图形象的描述了上面一系列代码所创建的对象