Android InputManager分析
本篇为鸡生蛋系列第二篇文章
- Linux input系统数据上报流程
- Android InputManager分析
- AMS startActivity()
- WMS 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.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<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.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<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.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<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.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(); //<---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.cpp
status_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.java
mInputMonitor.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.java
public 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.cpp
static 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_INPUT
void 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.cpp
int 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.cpp
int 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.java
private 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.java
private WindowManagerService(......) {
......
if(mInputManager != null) {
final InputChannel inputChannel = mInputManager.monitorInput(TAG_WM);
mPointerEventDispatcher = inputChannel != null
? new PointerEventDispatcher(inputChannel) : null;
@Override
public void registerPointerEventListener(PointerEventListener listener) {
mPointerEventDispatcher.registerInputEventListener(listener);
}
@Override
public 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;
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