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android /inputmanager-jni,Android InputManager分析

本篇为鸡生蛋系列第二篇文章

主要讲一下inputmanager相关的，即驱动把数据上报到用户空间后，用户空间到应用这么个流程，

在上一遍讲内核的input子系统时候，我们采取的反向分析，即由驱动出发，最后到input core，input子系统架构这么个由点到面的分析方法，

那分析inputmanager是否可采用这种方法如何呢？实际上，对于Android上层(Native framework/framework, c++/java)的分析，我一般

采用的是由上而下的分析，即从其初始化(main,构造，onFirstRef())开始, 通常在其初始化时候，会重一些很重要的上下层的连接，如果由下往上看，会麻烦点，

然后再结合实例，看看他的数据流向是如何的，或者一些重要的API, 例如对于Audio来说，可以结合播放音乐流程来分析整个系统架构。

简单说来，input到应用的流程为

EventHub监控并读取/dev/input下数据 --> 给InputReader 加工处理 --> 到InputDispacher --> 找到focused窗口并通过input channel发出去

相关代码目录:

Android 9.0 http://androidxref.com/9.0.0_r3/

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

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

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

frameworks/native/services/inputflinger/

1.1 初始化frameworks/base/services/java/com/android/server/SystemServer.java

startOtherServices() {

inputManager = new InputManagerService(context);

....

wm = WindowManagerService.main(context, inputManager,

ServiceManager.addService(Context.INPUT_SERVICE, inputManager,

/* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);

....

inputManager.setWindowManagerCallbacks(wm.getInputMonitor());

inputManager.start();

......

}

IMS(InputManagerService)的初始化，是从SystemServer开始的，通过搜索代码(如上)，我们可以看到构造了一个实例，

并做为参数传给了WMS, 由此我们也猜想，会和WMS有紧密的关系，然后

IMS设置了setWindowManagerCallbacks()并通过start()函数启动了，

SystemServer里有关IMS的就这么几个地方，我们再看下构造和start()具体的流程，与WMS的关联不分析。frameworks/base/services/core/java/com/android/server/input/InputManagerService.java

// Pointer to native input manager service object.

private final long mPtr;

public InputManagerService(Context context) {

this.mContext = context;

this.mHandler = new InputManagerHandler(DisplayThread.get().getLooper());

// config_useDevInputEventForAudioJack配置为true, 耳机事件可通过input上报

mUseDevInputEventForAudioJack =

context.getResources().getBoolean(R.bool.config_useDevInputEventForAudioJack);

......

mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());

......

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

}

public void start() {

Slog.i(TAG, "Starting input manager");

nativeStart(mPtr);

....

}

InputManagerService构造和start()主要也是调到JNI的 nativeInit() nativeStart().frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cpp

static jlong nativeInit(JNIEnv* env, jclass /* clazz */,

jobject serviceObj, jobject contextObj, jobject messageQueueObj) {

....

NativeInputManager* im = new NativeInputManager(contextObj, serviceObj,

messageQueue->getLooper());

im->incStrong(0);

return reinterpret_cast(im);

}

static void nativeStart(JNIEnv* env, jclass /* clazz */, jlong ptr) {

......

status_t result = im->getInputManager()->start();

......

}

nativeInit()又构造了一个 NativeInputManager(),该类可认为是上层JAVA和下层EventHub InputManager的桥梁，

nativeStart()通过 NativeInputManager最终调到 InputManager 的 start()方法NativeInputManager::NativeInputManager(jobject contextObj,

jobject serviceObj, const sp& looper) :

mLooper(looper), mInteractive(true) {

......

sp eventHub = new EventHub();

mInputManager = new InputManager(eventHub, this, this);

}

NativeInputManager()的构造又new了 EventHub 和 InputManager ，其中

eventHub做为参数传给了 InputManager()frameworks/native/services/inputflinger/EventHub.cpp

EventHub::EventHub(void) :

......{

acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);

mEpollFd = epoll_create(EPOLL_SIZE_HINT); // epoll机制

LOG_ALWAYS_FATAL_IF(mEpollFd < 0, "Could not create epoll instance. errno=%d", errno);

mINotifyFd = inotify_init(); // inotify机制

int result = inotify_add_watch(mINotifyFd, DEVICE_PATH, IN_DELETE | IN_CREATE); // 利用inotify监控 DEVICE_PATH(/dev/input)创建和删除

......

eventItem.events = EPOLLIN;

eventItem.data.u32 = EPOLL_ID_INOTIFY;

result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mINotifyFd, &eventItem); // 将inotify的fd添加到Epoll监控中

LOG_ALWAYS_FATAL_IF(result != 0, "Could not add INotify to epoll instance. errno=%d", errno);

int wakeFds[2];

result = pipe(wakeFds); //读写pipe, InputReader有事件时唤醒

LOG_ALWAYS_FATAL_IF(result != 0, "Could not create wake pipe. errno=%d", errno);

mWakeReadPipeFd = wakeFds[0];

mWakeWritePipeFd = wakeFds[1];

......

result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, &eventItem);

......

}

EventHub相当于一个集线器，把底层的USB, TOUCH,鼠标等事件统一收集上来，再给上层。

其构造函数当中利用inotify机制监控"/dev/input" 目录下设备的创建和删除，这样当有设备变更时就可以收到通知了，

构造函数也创建了所需要的mEpollFd，这个作为IO多路复用的机制，不清楚的可以查下如何使用，

构造里将mINotifyFd添加到了epoll里，在后续input设备创建的时候，也会把input设备的fd添加进去，这样当有数据或者设备变化时，

EventHub就可获取这些事件，进一步处理。

构造还创建了两个pipe,作为wakeup的读端和写端，当InputReader.cpp有事件(配置变更，monitor, 超时请求等)唤醒EventHub处理。InputManager::InputManager(

const sp& eventHub,

const sp& readerPolicy,

const sp& dispatcherPolicy) {

mDispatcher = new InputDispatcher(dispatcherPolicy);

mReader = new InputReader(eventHub, readerPolicy, mDispatcher); // eventHub又传给了 InputReader,最终他们俩是紧密联系在一起的

initialize(); // eventHub又传给了

}

void InputManager::initialize() {

mReaderThread = new InputReaderThread(mReader);

mDispatcherThread = new InputDispatcherThread(mDispatcher);

}

InputManager(),创建了InputDispatcher和InputReader实例并与对应的InputDispatcherThread InputReaderThread 线程关联

具体的我们不往下跟了，有兴趣的可以再看看，

至此，初始化流程告一段落。

InputManagerService.java的 start方法，最终到InputManager::start(),status_t InputManager::start() {

status_t result = mDispatcherThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY);

......

result = mReaderThread->run("InputReader", PRIORITY_URGENT_DISPLAY);

......

}

start() 方法目的就是让这两个线程跑起来，这样就可以不断的获取，处理消息了。

1.2 小结startOtherServices()/SystemServer.java

+ new InputManagerService(context) --> nativeInit(...) --> new NativeInputManager(...)

+ + new EventHub() --> inotify监控/dev/input + epoll + wake pipe

+ + new InputManager(eventHub,...)

+ + new InputDispatcher()

+ + new InputReader(eventHub,...)

+ + initialize()

+ + new InputReaderThread(mReader)

+ + new InputDispatcherThread(mDispatcher)

+ ^

+ +

+ inputManager.start() --> nativeStart(mPtr) --> im->getInputManager()->start() --> mDispatcherThread->run() mReaderThread->run()

2. 读取数据bool InputReaderThread::threadLoop() {

mReader->loopOnce();

return true;

}

bool InputDispatcherThread::threadLoop() {

mDispatcher->dispatchOnce();

return true;

}

上一小节讲到IMS通过start()函数，最终让InputReaderThread InputDispatcherThread两个线程跑起来了，

线程跑起来后，他们因为返回值为true, 所以他们会不断的loop, 即不断的读取，分发，读取，分发……

看上面几行代码，觉得整个过程很简单清晰，然而当我们继续跟下去看细节的时候，你能哇～～哇～～哇～～

这一节我们看看 mReader->loopOnce()，下一节继续看Dispatcher过程void InputReader::loopOnce() {

......

size_t count = mEventHub->getEvents(timeoutMillis, mEventBuffer, EVENT_BUFFER_SIZE);

......

if (count) {

processEventsLocked(mEventBuffer, count);

}

......// 通知dispather分发

mQueuedListener->flush();

}

InputReader的loopOnce()通过

EventHub getEvents()

获得元数据，然后通过

processEventsLocked()

进一步的处理，

然后再通过

mQueuedListener->flush()

通知InputDispatcher有数据了，该处理了

2.1 InputReader::loopOnce()之 EventHub->getEvents()size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSize) {

......

for (;;) {

nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);

// Reopen input devices if needed.

......

// Report any devices that had last been added/removed.

while (mClosingDevices) {

......

}

// 扫描设备

if (mNeedToScanDevices) {

mNeedToScanDevices = false;

scanDevicesLocked();

mNeedToSendFinishedDeviceScan = true;

}

......

// Grab the next input event.

bool deviceChanged = false;

while (mPendingEventIndex < mPendingEventCount) {

const struct epoll_event& eventItem = mPendingEventItems[mPendingEventIndex++];

......

ssize_t deviceIndex = mDevices.indexOfKey(eventItem.data.u32);

......

Device* device = mDevices.valueAt(deviceIndex);

if (eventItem.events & EPOLLIN) { //epoll事件

// 读取数据

int32_t readSize = read(device->fd, readBuffer,

sizeof(struct input_event) * capacity);

......

event->deviceId = deviceId; //

event->type = iev.type;

event->code = iev.code;

event->value = iev.value;

event += 1;

......

// Return now if we have collected any events or if we were explicitly awoken.

if (event != buffer || awoken) {

break;

}

// Poll for events. Mind the wake lock dance!

......

int pollResult = epoll_wait(mEpollFd, mPendingEventItems, EPOLL_MAX_EVENTS, timeoutMillis);

......

return event - buffer;

}

getEvents()会检查是否需要扫描设备，如果需要的话，则会建立设备KeyedVector向量表，

之后若有数据到来则通过read()函数读取数据，返回RawEvent* buffer给processEventsLocked()进行下一步处理，

若啥事都没有通过epoll_wait()阻塞等待。

本来数据的读取(read())比较简单, 这里只列下设备扫描流程，作为个人笔记，有兴趣的可以看下EventHub::scanDevicesLocked() --> scanDirLocked(DEVICE_PATH) "/dev/input" --> while处理 openDeviceLocked() -->

status_t EventHub::openDeviceLocked(const char *devicePath) {

......

int fd = open(devicePath, O_RDWR | O_CLOEXEC | O_NONBLOCK);

......//一大堆ioctl的信息获取

if(ioctl(......)) {

......//生成唯一的 deviceId,和device, 做为mdevices的 key, value. 以后的操作会常用到这个deviceId

// Allocate device. (The device object takes ownership of the fd at this point.)

int32_t deviceId = mNextDeviceId++;

Device* device = new Device(fd, deviceId, String8(devicePath), identifier);

......

// Load the configuration file for the device.

// 加载这个设备的 idc(Input Device Configuration)配置文件

loadConfigurationLocked(device);

......//能力获取和分类

// Figure out the kinds of events the device reports.

ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(device->keyBitmask)), device->keyBitmask);

ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(device->absBitmask)), device->absBitmask);

ioctl(fd, EVIOCGBIT(EV_REL, sizeof(device->relBitmask)), device->relBitmask);

...... // 设备分类

device->classes |= ......;

......

//加入到epoll当中

if (registerDeviceForEpollLocked(device) != OK) {

......

configureFd(device);

......//加入mDevices并更新 mOpeningDevices 链表

addDeviceLocked(device);

return OK;

}// 对于我们的触屏来说class为

// See if this is a touch pad.

// Is this a new modern multi-touch driver?

if (test_bit(ABS_MT_POSITION_X, device->absBitmask)

&& test_bit(ABS_MT_POSITION_Y, device->absBitmask)) {

......

if (test_bit(BTN_TOUCH, device->keyBitmask) || !haveGamepadButtons) {

device->classes |= INPUT_DEVICE_CLASS_TOUCH | INPUT_DEVICE_CLASS_TOUCH_MT;

}

......//之后还会加载虚拟key.

// Configure virtual keys.

if ((device->classes & INPUT_DEVICE_CLASS_TOUCH)) {

// Load the virtual keys for the touch screen, if any.

// We do this now so that we can make sure to load the keymap if necessary.

status_t status = loadVirtualKeyMapLocked(device);

status_t EventHub::loadVirtualKeyMapLocked(Device* device) {

// The virtual key map is supplied by the kernel as a system board property file.

......

path.append("/sys/board_properties/virtualkeys.");

path.append(device->identifier.name);

......

return VirtualKeyMap::load(path, &device->virtualKeyMap);

addDeviceLocked()即添加到

EventHub.h KeyedVector mDevices;

并更新链表mOpeningDevicesvoid EventHub::addDeviceLocked(Device* device) {

mDevices.add(device->id, device);

device->next = mOpeningDevices;

mOpeningDevices = device;

}

另外要注意一点的是，在scanDevicesLocked()时候也会创建虚拟键盘。void EventHub::scanDevicesLocked() {

status_t res = scanDirLocked(DEVICE_PATH);

.......

// 创建虚拟键盘

if (mDevices.indexOfKey(VIRTUAL_KEYBOARD_ID) < 0) {

createVirtualKeyboardLocked();

}

2.2 InputReader::loopOnce()之 processEventsLocked

mEventHub->getEvents(), 反回元数据后，传给 processEventsLocked()进一步处理

元数据的定义如下，主要记录了时间，设备id, type, code, value.struct RawEvent {

nsecs_t when;

int32_t deviceId;

int32_t type;

int32_t code;

int32_t value;

};

其中的deviceId起了个连接作用，用于标识eventhub和iputreader中的设备，void InputReader::processEventsLocked(const RawEvent* rawEvents, size_t count) {

for (const RawEvent* rawEvent = rawEvents; count;) {

int32_t type = rawEvent->type;

size_t batchSize = 1;

if (type < EventHubInterface::FIRST_SYNTHETIC_EVENT) {

int32_t deviceId = rawEvent->deviceId;

......

processEventsForDeviceLocked(deviceId, rawEvent, batchSize);

......

case EventHubInterface::DEVICE_ADDED:

addDeviceLocked(rawEvent->when, rawEvent->deviceId);

case EventHubInterface::DEVICE_REMOVED:

......

case EventHubInterface::FINISHED_DEVICE_SCAN:

......

}

processEventsLocked()函数有个

processEventsForDeviceLocked() 对于对数据的处理，

另外还根据type, 处理了对设备添加移除，扫描的处理，

大家就有点奇怪了，咦，eventhub扫描设备的时候，不是有处理添加设备吗？

咋这儿又有添加设备了？而且看代码，两者都有个mDevices变量EventHub.h KeyedVector mDevices;

InputReader.h KeyedVector mDevices;

上面可看到两者value类型不同，他们之间的key 即deviceID是相同的，

其实我个人认为EventHub中的Device为设备的本身属性，是下层设备的实例化，

而InputReader中的InputDevice为更高层次的抽象，主要用于往上层处理数据，

addDeviceLocked()过程中还会根据input设备的不同属性设置不同的Mapper事件转换器。

我们先看下processEventsForDeviceLocked()过程:void InputReader::processEventsForDeviceLocked(int32_t deviceId,

const RawEvent* rawEvents, size_t count) {

ssize_t deviceIndex = mDevices.indexOfKey(deviceId);

......

InputDevice* device = mDevices.valueAt(deviceIndex);

......

device->process(rawEvents, count);

}

void InputDevice::process(const RawEvent* rawEvents, size_t count) {

// Process all of the events in order for each mapper.

......

// 可能会有多个mapper

size_t numMappers = mMappers.size();

for (const RawEvent* rawEvent = rawEvents; count != 0; rawEvent++) {

......

for (size_t i = 0; i < numMappers; i++) {

InputMapper* mapper = mMappers[i];

mapper->process(rawEvent);

}

......

}

processEventsForDeviceLocked() --> device->process() --> mapper->process()

最终数据的处理也是通过mapper来处理的，所以我们还得看下mapper咋添加的

Mapper添加

mapper的添加是根据分类来添加的, 以触屏为例frameworks/native/services/inputflinger/InputReader.cpp

InputReader::processEventsLocked() --> addDeviceLocked() --> createDeviceLocked() -->

// Touchscreens and touchpad devices.

if (classes & INPUT_DEVICE_CLASS_TOUCH_MT) {

device->addMapper(new MultiTouchInputMapper(device));

} else if (classes & INPUT_DEVICE_CLASS_TOUCH) {

device->addMapper(new SingleTouchInputMapper(device));

}

所以触屏的最后数据处理函数会调到

MultiTouchInputMapper的process函数不再详细看void MultiTouchInputMapper::process(const RawEvent* rawEvent) {

TouchInputMapper::process(rawEvent);

mMultiTouchMotionAccumulator.process(rawEvent);

}

2.3 InputReader数据如何到InputDispatcher的？

InputReader::loopOnce() 数据处理完后便调用 mQueuedListener->flush() 通知 InputDispatcher 该处理数据了。void QueuedInputListener::flush() {

size_t count = mArgsQueue.size();

for (size_t i = 0; i < count; i++) {

NotifyArgs* args = mArgsQueue[i];

args->notify(mInnerListener);

delete args;

}

mArgsQueue.clear();

}

flush()方法即把mArgsQueue Vector一个个取出来，然后再调用notify()方法，

那我们肯定想要知道

1. 数据是咋压入 mArgsQueue的？

2. notify() 后续流程咋把数据给到 InputDispatcher

1.void QueuedInputListener::notifyConfigurationChanged(

const NotifyConfigurationChangedArgs* args) {

mArgsQueue.push(new NotifyConfigurationChangedArgs(*args));

}

void QueuedInputListener::notifyKey(const NotifyKeyArgs* args) {

mArgsQueue.push(new NotifyKeyArgs(*args));

}

void QueuedInputListener::notifyMotion(const NotifyMotionArgs* args) {

mArgsQueue.push(new NotifyMotionArgs(*args));

}

void QueuedInputListener::notifySwitch(const NotifySwitchArgs* args) {

mArgsQueue.push(new NotifySwitchArgs(*args));

}

void QueuedInputListener::notifyDeviceReset(const NotifyDeviceResetArgs* args) {

mArgsQueue.push(new NotifyDeviceResetArgs(*args));

}

在QueuedInputListener中看到 notifyConfigurationChanged() notifyKey() notifyMotion() notifySwitch() notifyDeviceReset()

当有配置变化或事件时，都会新创建个notify args实例(都继承自NotifyArgs)，然后push到mArgsQueue，

以触屏事件为例，push流程为:TouchInputMapper::sync() --> processRawTouches() --> cookAndDispatch() --> dispatchTouches() --> dispatchMotion()

--> NotifyMotionArgs args(...) getListener()->notifyMotion(&args) -->

frameworks/native/services/inputflinger/InputListener.cpp

void QueuedInputListener::notifyMotion(const NotifyMotionArgs* args) {

mArgsQueue.push(new NotifyMotionArgs(*args));

}InputReader::loopOnce() --> QueuedInputListener::flush() --> for args->notify(mInnerListener);

以触屏NotifyMotionArgs为例，其调用到void NotifyMotionArgs::notify(const sp& listener) const {

listener->notifyMotion(this);

}

注意其 listener 为 InputDispatcher (InputDispatcher 继承自 InputDispatcherInterface class InputDispatcher : public InputDispatcherInterface),frameworks/native/services/inputflinger/InputManager.cpp

mDispatcher = new InputDispatcher(dispatcherPolicy); mReader = new InputReader(..., ..., mDispatcher); --> InputReader::InputReader(..., ..., ...listener) --> new QueuedInputListener(listener);

所以最终就调到了

InputDispatcher::notifyMotion()void InputDispatcher::notifyMotion(const NotifyMotionArgs* args) {

......// 合法性检查

if (!validateMotionEvent(args->action, args->actionButton,

args->pointerCount, args->pointerProperties)) {

......// 预处理

mPolicy->interceptMotionBeforeQueueing(args->eventTime, /*byref*/ policyFlags);

......

if (shouldSendMotionToInputFilterLocked(args)) {

mLock.unlock();

MotionEvent event;

event.initialize(args->deviceId, args->source, args->action, args->actionButton,

args->flags, args->edgeFlags, args->metaState, args->buttonState,

0, 0, args->xPrecision, args->yPrecision,

args->downTime, args->eventTime,

args->pointerCount, args->pointerProperties, args->pointerCoords);

policyFlags |= POLICY_FLAG_FILTERED;

// 过滤

if (!mPolicy->filterInputEvent(&event, policyFlags)) {

return; // event was consumed by the filter

}

mLock.lock();

}

// Just enqueue a new motion event.

MotionEntry* newEntry = new MotionEntry(args->eventTime,

args->deviceId, args->source, policyFlags,

args->action, args->actionButton, args->flags,

args->metaState, args->buttonState,

args->edgeFlags, args->xPrecision, args->yPrecision, args->downTime,

args->displayId,

args->pointerCount, args->pointerProperties, args->pointerCoords, 0, 0);

// 入队

needWake = enqueueInboundEventLocked(newEntry);

mLock.unlock();

} // release lock

if (needWake) {

// 唤醒

mLooper->wake();

}

notifyMotion()会先检查合法性，然后预处理，如果需要过滤则进行过滤处理，

否则构建 MotionEntry，并入队，随后将looper唤醒。bool InputDispatcher::enqueueInboundEventLocked(EventEntry* entry) {

bool needWake = mInboundQueue.isEmpty();

// 入队

mInboundQueue.enqueueAtTail(entry);

......

}

InputReader这一侧大至就分析完了，数据从InputReader传到InputDispatcher也清楚了，

接下来看看数据分发。

3. 分发数据

在开头也讲到，InputDispatcherThread里不断的loop,调用dispatchOnce()进行数据的分发。frameworks/native/services/inputflinger/InputDispatcher.cpp

void InputDispatcher::dispatchOnce() {

......

// Run a dispatch loop if there are no pending commands.

// The dispatch loop might enqueue commands to run afterwards.

if (!haveCommandsLocked()) {

// 如果命令列队为空，进行事件分发

dispatchOnceInnerLocked(&nextWakeupTime);

}

//如果looper里没有信息，会阻塞，直到timeoutMillis超时

mLooper->pollOnce(timeoutMillis);

}

dispatchOnce()里如果命令处理完了，才会调用dispatchOnceInnerLocked()进行事件处理。void InputDispatcher::dispatchOnceInnerLocked(nsecs_t* nextWakeupTime) {

.....//如果没有event,抓取一个

// Ready to start a new event.

// If we don't already have a pending event, go grab one.

if (! mPendingEvent) {

if (mInboundQueue.isEmpty()) {

......

} else {

// Inbound queue has at least one entry.

mPendingEvent = mInboundQueue.dequeueAtHead(); //

traceInboundQueueLengthLocked();

}

......//一些错误处理，包括anr时间重置，略过

switch (mPendingEvent->type) {

case EventEntry::TYPE_CONFIGURATION_CHANGED: ....

case EventEntry::TYPE_DEVICE_RESET: ....

case EventEntry::TYPE_KEY: .....

......//对我们的touch来说是motion事件

case EventEntry::TYPE_MOTION: {

MotionEntry* typedEntry = static_cast(mPendingEvent);

if (dropReason == DROP_REASON_NOT_DROPPED && isAppSwitchDue) {

dropReason = DROP_REASON_APP_SWITCH;

}

if (dropReason == DROP_REASON_NOT_DROPPED

&& isStaleEventLocked(currentTime, typedEntry)) {

dropReason = DROP_REASON_STALE;

}

if (dropReason == DROP_REASON_NOT_DROPPED && mNextUnblockedEvent) {

dropReason = DROP_REASON_BLOCKED;

}

//分发事件

done = dispatchMotionLocked(currentTime, typedEntry,

&dropReason, nextWakeupTime);

break;

}

......

}

dispatchOnceInnerLocked从mInboundQueue队列中取出之前的MotionEntry，

然后错误处理，对于触屏事件做dispatchMotionLocked()bool InputDispatcher::dispatchMotionLocked(

nsecs_t currentTime, MotionEntry* entry, DropReason* dropReason, nsecs_t* nextWakeupTime) {

......// 是否为 point event

bool isPointerEvent = entry->source & AINPUT_SOURCE_CLASS_POINTER;

// Identify targets.

Vector inputTargets;

......

if (isPointerEvent) {

// Pointer event. (eg. touchscreen)

injectionResult = findTouchedWindowTargetsLocked(currentTime,

entry, inputTargets, nextWakeupTime, &conflictingPointerActions);

} else {

// Non touch event. (eg. trackball)

injectionResult = findFocusedWindowTargetsLocked(currentTime,

entry, inputTargets, nextWakeupTime);

}

......

dispatchEventLocked(currentTime, entry, inputTargets);

return true;

}

对于point event，会先用

findTouchedWindowTargetsLocked() 找到目标窗口，否则用

findFocusedWindowTargetsLocked() 找到目标窗口

对我们的触屏来说，包含有该属性

frameworks/native/include/android/input.h

AINPUT_SOURCE_TOUCHSCREEN = 0x00001000 | AINPUT_SOURCE_CLASS_POINTER,

找到目标窗口后，再用 dispatchEventLocked() 发给目标窗口dispatchEventLocked() --> prepareDispatchCycleLocked() --> enqueueDispatchEntriesLocked()

void InputDispatcher::dispatchEventLocked(nsecs_t currentTime,

EventEntry* eventEntry, const Vector& inputTargets) {

......

for (size_t i = 0; i < inputTargets.size(); i++) {

const InputTarget& inputTarget = inputTargets.itemAt(i);

ssize_t connectionIndex = getConnectionIndexLocked(inputTarget.inputChannel);

if (connectionIndex >= 0) {

sp connection = mConnectionsByFd.valueAt(connectionIndex);

prepareDispatchCycleLocked(currentTime, connection, eventEntry, &inputTarget);

......

}

void InputDispatcher::prepareDispatchCycleLocked(nsecs_t currentTime,

......

// Not splitting. Enqueue dispatch entries for the event as is.

enqueueDispatchEntriesLocked(currentTime, connection, eventEntry, inputTarget);

}void InputDispatcher::enqueueDispatchEntriesLocked(nsecs_t currentTime,

const sp& connection, EventEntry* eventEntry, const InputTarget* inputTarget) {

bool wasEmpty = connection->outboundQueue.isEmpty();

// Enqueue dispatch entries for the requested modes.