本篇为鸡生蛋系列第二篇文章
- Linux input系统数据上报流程 https://segmentfault.com/a/11...
- Android InputManager分析
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
参考文档:
十分钟了解Android触摸事件原理（InputManagerService）
https://www.jianshu.com/p/f05...
android控件系统:输入事件在控件树中的传递
https://blog.csdn.net/renshug...
https://blog.csdn.net/renshug...
InputManagerService分析一：IMS的启动与事件传递
https://blog.csdn.net/lilian0...
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.javastartOtherServices() { 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.cppstatic 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<jlong>(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>& looper) : mLooper(looper), mInteractive(true) {...... sp<EventHub> 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.cppEventHub::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<EventHubInterface>& eventHub, const sp<InputReaderPolicyInterface>& readerPolicy, const sp<InputDispatcherPolicyInterface>& 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; // <-- 设备id 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<int32_t, Device*> mDevices;
并更新链表mOpeningDevices
void 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<int32_t, Device*> mDevices;InputReader.h KeyedVector<int32_t, InputDevice*> 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.cppInputReader::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.cppvoid 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<InputListenerInterface>& 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.cppmDispatcher = 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.cppvoid 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(); //<---从mInboundQueue队头抓个 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<MotionEntry*>(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<InputTarget> 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<InputTarget>& 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> 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>& connection, EventEntry* eventEntry, const InputTarget* inputTarget) { bool wasEmpty = connection->outboundQueue.isEmpty(); // Enqueue dispatch entries for the requested modes. enqueueDispatchEntryLocked(connection, eventEntry, inputTarget, InputTarget::FLAG_DISPATCH_AS_HOVER_EXIT); enqueueDispatchEntryLocked(connection, eventEntry, inputTarget, InputTarget::FLAG_DISPATCH_AS_OUTSIDE); enqueueDispatchEntryLocked(connection, eventEntry, inputTarget, InputTarget::FLAG_DISPATCH_AS_HOVER_ENTER); enqueueDispatchEntryLocked(connection, eventEntry, inputTarget, InputTarget::FLAG_DISPATCH_AS_IS); enqueueDispatchEntryLocked(connection, eventEntry, inputTarget, InputTarget::FLAG_DISPATCH_AS_SLIPPERY_EXIT); enqueueDispatchEntryLocked(connection, eventEntry, inputTarget, InputTarget::FLAG_DISPATCH_AS_SLIPPERY_ENTER); // If the outbound queue was previously empty, start the dispatch cycle going. if (wasEmpty && !connection->outboundQueue.isEmpty()) { startDispatchCycleLocked(currentTime, connection); }}enqueueDispatchEntryLocked()会根据flag mode进行比较，然后加入到connection的outboundQueue里
connection->outboundQueue.enqueueAtTail(dispatchEntry);
然后再调用
startDispatchCycleLocked()最终通过socket把事件发出去
void InputDispatcher::startDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection) {...... case EventEntry::TYPE_MOTION: {...... // Publish the motion event. status = connection->inputPublisher.publishMotionEvent(dispatchEntry->seq, motionEntry->deviceId, motionEntry->source, motionEntry->displayId, dispatchEntry->resolvedAction, motionEntry->actionButton, dispatchEntry->resolvedFlags, motionEntry->edgeFlags, motionEntry->metaState, motionEntry->buttonState, xOffset, yOffset, motionEntry->xPrecision, motionEntry->yPrecision, motionEntry->downTime, motionEntry->eventTime, motionEntry->pointerCount, motionEntry->pointerProperties, usingCoords); break; }......frameworks/native/libs/input/InputTransport.cppstatus_t InputPublisher::publishMotionEvent(...... InputMessage msg; msg.header.type = InputMessage::TYPE_MOTION;...... // 通过socket发送 return mChannel->sendMessage(&msg);}4. 数据接收
数据发送后，又被谁接收到了呢？之后流程又如何呢？
input数据主要有两种，一个应用，一个MonitoringChannel，
这里仅简单的列举下，详细的请看看参考文档
4.1 App 接收
对于应用的接收，需要看input channel是咋建立的，
然后看看findTouchedWindowTargetsLocked()，咋找到目录窗口，该函数很复杂，
但有个比较重要的是查询 mWindowHandles, 该变量在setInputWindows()设置,
WindowManagerService.javamInputMonitor.updateInputWindowsLw(false /*force*/); in addWindow() -+mInputMonitor.updateInputWindowsLw(true /*force*/); in postWindowRemoveCleanupLocked() +mInputMonitor.updateInputWindowsLw(true /*force*/); in relayoutWindow() +mInputMonitor.updateInputWindowsLw(true /*force*/); in relayoutWindow() +--> updateInputWindowsLw() -->mInputMonitor.updateInputWindowsLw(true /*force*/); in removeWindowToken() +mInputMonitor.updateInputWindowsLw(true /*force*/); in startPositioningLocked() +mInputMonitor.updateInputWindowsLw(true /*force*/); in startPositioningLocked() +mInputMonitor.updateInputWindowsLw(true /*force*/); in finishPositioning() -+InputMonitor.java updateInputWindowsLw() +--> mUpdateInputForAllWindowsConsumer.updateInputWindows(inDrag) +--> updateInputWindows() +--> InputManagerService.java setInputWindows() +--> nativeSetInputWindows() +--> im->setInputWindows (NativeInputManager::setInputWindows()) +--> mInputManager->getDispatcher()->setInputWindows() +-->void InputDispatcher::setInputWindows(const Vector<sp<InputWindowHandle> >& inputWindowHandles) {...... mWindowHandles = inputWindowHandles;应用添加窗口设置mWindowHandles如上。在addWindow() relayoutWindow()...过程中都可能设置该变量
frameworks/base/core/java/android/view/ViewRootImpl.javapublic void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {...... // addToDisplay() 将调用WMS mService.addWindow() res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes, getHostVisibility(), mDisplay.getDisplayId(), mWinFrame, mAttachInfo.mContentInsets, mAttachInfo.mStableInsets, mAttachInfo.mOutsets, mAttachInfo.mDisplayCutout, mInputChannel);...... // mInputEventReceiver = new WindowInputEventReceiver(mInputChannel, Looper.myLooper()); }对应用来说在setView() 时会调用mWindowSession.addToDisplay(),很后调用addWindow(), 然后win.openInputChannel(outInputChannel)等建立channel操作
addToDisplay() 之会，会将mInputChannel looper，通过 WindowInputEventReceiver绑在一起，
这样当有数据到来时在looper里面处理。
WindowInputEventReceiver()流程如下
WindowInputEventReceiver() --> InputEventReceiver.java InputEventReceiver() --> nativeInit() -->frameworks/base/core/jni/android_view_InputEventReceiver.cppstatic jlong nativeInit(JNIEnv* env, jclass clazz, jobject receiverWeak, jobject inputChannelObj, jobject messageQueueObj) {...... sp<NativeInputEventReceiver> receiver = new NativeInputEventReceiver(env, receiverWeak, inputChannel, messageQueue); status_t status = receiver->initialize();......}initialize() (NativeInputEventReceiver::initialize())--> setFdEvents(ALOOPER_EVENT_INPUT) -->// 注意事件类型为 ALOOPER_EVENT_INPUTvoid NativeInputEventReceiver::setFdEvents(int events) { if (mFdEvents != events) { mFdEvents = events; int fd = mInputConsumer.getChannel()->getFd(); if (events) { mMessageQueue->getLooper()->addFd(fd, 0, events, this, NULL);system/core/libutils/Looper.cppint Looper::addFd(int fd, int ident, int events, const sp<LooperCallback>& callback, void* data) {......// 将input channel的fd加入到epoll监控中 int epollResult = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, fd, & eventItem);** 当socket接收到数据时，通过handle来处理
android_view_InputEventReceiver.cppint NativeInputEventReceiver::handleEvent(int receiveFd, int events, void* data) {......// ALOOPER_EVENT_INPUT 事件 if (events & ALOOPER_EVENT_INPUT) { JNIEnv* env = AndroidRuntime::getJNIEnv(); status_t status = consumeEvents(env, false /*consumeBatches*/, -1, NULL); mMessageQueue->raiseAndClearException(env, "handleReceiveCallback"); return status == OK || status == NO_MEMORY ? 1 : 0; }......}handleEvent() --> consumeEvents() -->status_t NativeInputEventReceiver::consumeEvents(JNIEnv* env, bool consumeBatches, nsecs_t frameTime, bool* outConsumedBatch) {...... status_t status = mInputConsumer.consume(&mInputEventFactory, //取数据...... if (inputEventObj) {... env->CallVoidMethod(receiverObj.get(), gInputEventReceiverClassInfo.dispatchInputEvent, seq, inputEventObj, //调用 dispatchInputEvent()......}-->frameworks/base/core/java/android/view/InputEventReceiver.java dispatchInputEvent() --> onInputEvent() --> final class WindowInputEventReceiver extends InputEventReceiver {...... @Override public void onInputEvent(InputEvent event, int displayId) { enqueueInputEvent(event, this, 0, true); }void enqueueInputEvent(InputEvent event, InputEventReceiver receiver, int flags, boolean processImmediately) {...... if (processImmediately) { doProcessInputEvents(); // --> deliverInputEvent(q); } else { scheduleProcessInputEvents(); }}ViewRootImpl.javaprivate void deliverInputEvent(QueuedInputEvent q) {...... InputStage stage; if (q.shouldSendToSynthesizer()) { stage = mSyntheticInputStage; } else { // mFirstPostImeInputStage = earlyPostImeStage; new EarlyPostImeInputStage(nativePostImeStage); 注意参数为nativePostImeStage，在 apply(q, onProcess(q)) 返回forward时会用到 stage = q.shouldSkipIme() ? mFirstPostImeInputStage : mFirstInputStage; }...... if (stage != null) { handleWindowFocusChanged(); stage.deliver(q);......}stage.deliver --> apply(q, onProcess(q)) --> EarlyPostImeInputStage onProcess() --> processPointerEvent() --> (EarlyPostImeInputStage-->NativePostImeInputStage-->ViewPostImeInputStage-->SyntheticInputStage;)ViewPostImeInputStage mView.dispatchPointerEvent(event)View.java dispatchPointerEvent() +-->View.java dispatchTouchEvent() --> li.mOnTouchListener.onTouch(this, event) onTouchEvent(event) + +--> ViewGroup.java dispatchTouchEvent()4.2 input monitor笔记
在分发input数据时，会把 mMonitoringChannels 加入到目标中，然后通过socket也发给该目标，
InputDispatcher::dispatchMotionLocked() --> addMonitoringTargetsLocked() --> for mMonitoringChannels
在WMS时构造，会通过monitorInput()创建，
之后别的服务可通过WMS registerPointerEventListener() unregisterPointerEventListener() 以listener方式获取数据
frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.javaprivate WindowManagerService(......) {...... if(mInputManager != null) { final InputChannel inputChannel = mInputManager.monitorInput(TAG_WM); mPointerEventDispatcher = inputChannel != null ? new PointerEventDispatcher(inputChannel) : null;@Overridepublic void registerPointerEventListener(PointerEventListener listener) { mPointerEventDispatcher.registerInputEventListener(listener);}@Overridepublic void unregisterPointerEventListener(PointerEventListener listener) { mPointerEventDispatcher.unregisterInputEventListener(listener);}monitorInput()流程如下：
InputManagerService.java monitorInput() +--> nativeRegisterInputChannel(......, true); +--> NativeInputManager::registerInputChannel() +--> mInputManager->getDispatcher()->registerInputChannel() -->status_t InputDispatcher::registerInputChannel(const sp<InputChannel>& inputChannel, const sp<InputWindowHandle>& inputWindowHandle, bool monitor) {...... if (monitor) { mMonitoringChannels.push(inputChannel); }......}个人笔记
数据的转存
从slot --> RawPointerData --> cookAndDispatch() cookPointerData()进一步处理将值给
mCurrentCookedState.cookedPointerData，主要为
cookedPointerData.pointerCoords cookedPointerData.pointerProperties
dispatchMotion()时参数传入cookedPointerData,进一步将数据封装为
NotifyMotionArgs
dispatchMotion(when, policyFlags, mSource,
......
mCurrentCookedStat.cookedPointerData.pointerProperties, mCurrentCookedStat.cookedPointerData.pointerCoords, mCurrentCookedStat.cookedPointerData.idToIndex,......
TouchInputMapper::sync() +-> syncTouch(when, next); --> 数据从slot到outState->rawPointerData.pointers[outCount];
+-> processRawTouches() --> cookAndDispatch() --> dispatchTouches() --> dispatchMotion()数据处理完后将 NotifyMotionArgs 压入mArgsQueue
TouchInputMapper::dispatchMotion() --> getListener()->notifyMotion(&args) -->
frameworks/native/services/inputflinger/InputListener.cpp
void NotifyMotionArgs::notify(const sp<InputListenerInterface>& listener) const {
listener->notifyMotion(this);}
void QueuedInputListener::notifyMotion(const NotifyMotionArgs* args) {
mArgsQueue.push(new NotifyMotionArgs(*args));}
void MultiTouchInputMapper::syncTouch(nsecs_t when, RawState* outState) {
size_t inCount = mMultiTouchMotionAccumulator.getSlotCount();......
for (size_t inIndex = 0; inIndex < inCount; inIndex++) { const MultiTouchMotionAccumulator::Slot* inSlot = mMultiTouchMotionAccumulator.getSlot(inIndex);......
RawPointerData::Pointer& outPointer = outState->rawPointerData.pointers[outCount]; outPointer.x = inSlot->getX(); outPointer.y = inSlot->getY();......
}
数据从MultiTouchMotionAccumulator::Slot 转到 RawPointerData::Pointer
void TouchInputMapper::processRawTouches(bool timeout) {....//在处理mRawStatesPending数据时，一个一个取出给mCurrentRawState，然后 cookAndDispatch进一步处理 for(count = 0; count < N; count++) { const RawState& next = mRawStatesPending[count];......//给mCurrentRawState mCurrentRawState.copyFrom(next);......//cookAndDispatch加工并分发 cookAndDispatch(mCurrentRawState.when);void TouchInputMapper::cookPointerData() { uint32_t currentPointerCount = mCurrentRawState.rawPointerData.pointerCount; mCurrentCookedState.cookedPointerData.clear();......//将数据进一步的处理，例如，计算旋转后的值 // Walk through the the active pointers and map device coordinates onto // surface coordinates and adjust for display orientation. for (uint32_t i = 0; i < currentPointerCount; i++) { const RawPointerData::Pointer& in = mCurrentRawState.rawPointerData.pointers[i];...... case DISPLAY_ORIENTATION_90: x = float(yTransformed - mRawPointerAxes.y.minValue) * mYScale + mYTranslate; y = float(mRawPointerAxes.x.maxValue - xTransformed) * mXScale + mXTranslate;......//将值给 cookedPointerData.pointerCoords // Write output coords. PointerCoords& out = mCurrentCookedState.cookedPointerData.pointerCoords[i]; out.clear(); out.setAxisValue(AMOTION_EVENT_AXIS_X, x); out.setAxisValue(AMOTION_EVENT_AXIS_Y, y); out.setAxisValue(AMOTION_EVENT_AXIS_PRESSURE, pressure);......//将值给 cookedPointerData.pointerProperties // Write output properties. PointerProperties& properties = mCurrentCookedState.cookedPointerData.pointerProperties[i]; uint32_t id = in.id; properties.clear(); properties.id = id; properties.toolType = in.toolType; // Write id index. mCurrentCookedState.cookedPointerData.idToIndex[id] = i;......