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前言
关于为什么会有这“framework必会系列”文章?对,卷王太多了。。
关于现在应用开发现已饱和的大环境下,作为一个多年Android开发,强逼咱们Android开发往更深层次的framework层走,于是就有了这么个系列。
好了这都不谈了,咱们来进入正文。
上一篇文章咱们解说了Android输入体系事情读取,这儿再来回顾下:
- 开机后SystemServer发动进程中创立了InputManagerService,InputManagerService结构办法中在native层创立了NativeInputManager目标。
- NativeInputManager结构办法中又创立了一个InputManager目标,InputManager结构办法中又创立了InputDispatcher和InputReader目标以及他们两个工作对应的线程 InputDispatcherThread和InputReaderThread。
- InputManagerService在实例化完成后,SystemServer发动进程会继续调用其start办法发动IMS,实践是发动InputDispatcherThread和InputReaderThread线程。
- 在InputReaderThread线程中运用EventHub的getEvents办法去设备节点/dev/input下面获取节点数据。并在事情加工完成后并唤醒InputDispatcherThread线程去处理。
以上便是整个输入事情读取的进程,用一张总结关系:
本篇文章首要解说关于IMS的输入事情分发的进程
事情分发流程
为了让咱们不会迷失在源码中,笔者先抛出几个问题,然后带着问题去看源码。
- 问题1:窗口什么时分传入IMS输入体系的?IMS是怎么找到对应的Window窗口的?
- 问题2:IMS和WMS是经过什么方式通讯将事情分发出去的?
这儿再提早放一张图让咱们对输入事情模型有个概念,然后再结合源码去剖析。
下面正式开始剖析源码:
事情分发进口确定
上篇文章咱们讲到事情读取流程将事情放入封装为KeyEntry放入到mInboundQueue行列的尾部tail,并唤醒InputDispatcherThread线程,就以这儿为进口、
void InputDispatcher::notifyKey(const NotifyKeyArgs* args) {
...
KeyEntry* newEntry = new KeyEntry(args->eventTime,args->deviceId, ...);//1
needWake = enqueueInboundEventLocked(newEntry); //2
if (needWake) {
mLooper->wake();//3
}
}
bool InputDispatcher::enqueueInboundEventLocked(EventEntry* entry) {
...
mInboundQueue.enqueueAtTail(entry);
}
事情分发线程唤醒
进入InputDispatcherThread的threadLoop办法: 关于Thread的threadLoop办法解说现已在上篇文章讲过,这儿不再重复。
bool InputDispatcherThread::threadLoop() {
mDispatcher->dispatchOnce();//mDispatcher 是InputDispatcher类型目标
return true;
}
void InputDispatcher::dispatchOnce() {
...
if (!haveCommandsLocked()) {//1
dispatchOnceInnerLocked(&nextWakeupTime);
}
...
if (runCommandsLockedInterruptible()) {//2
nextWakeupTime = LONG_LONG_MIN;
}
mLooper->pollOnce(timeoutMillis);
}
注释1处判别是否有指令需求履行,假如没有,则调用dispatchOnceInnerLocked去处理输入事情,假如有,则优先调用runCommandsLockedInterruptible处理事情, 为了让线程能够当即进入事情处理,将nextWakeupTime 设置为LONG_LONG_MIN,这样线程在指令履行结束后能够当即被唤醒去处理输入事情。
从这儿能够看出dispatchOnce首要是做了两个功用:1.履行指令 2.处理输入事情,且指令履行优先级高于输入事情处理。 这儿的指令例如:对waitQueue中的事情进行出栈,后面会讲到。
进入注释2输入事情处理:dispatchOnceInnerLocked
void InputDispatcher::dispatchOnceInnerLocked(nsecs_t* nextWakeupTime) {
switch (mPendingEvent->type) {
...
case EventEntry::TYPE_KEY: {
KeyEntry* typedEntry = static_cast<KeyEntry*>(mPendingEvent);
...
done = dispatchKeyLocked(currentTime, typedEntry, &dropReason, nextWakeupTime);
break;
}
case EventEntry::TYPE_MOTION: {
MotionEntry* typedEntry = static_cast<MotionEntry*>(mPendingEvent);
...
done = dispatchMotionLocked(currentTime, typedEntry,
&dropReason, nextWakeupTime);
break;
}
if (done) {
...
releasePendingEventLocked();
*nextWakeupTime = LONG_LONG_MIN; // force next poll to wake up immediately
}
}
dispatchOnceInnerLocked办法首要是依据事情的类型调用不同的处理办法。 咱们拿TYPE_KEY 按键事情来作为主线,关于TYPE_MOTION触摸事情处理逻辑都是差不过的,感兴趣的同学能够自行阅览源码。 在事情处理分发结束后会调用releasePendingEventLocked里边会释放对应的内存资源
mPendingEvent代表当时需求处理的输入事情,传递给dispatchKeyLocked去处理
bool InputDispatcher::dispatchKeyLocked(nsecs_t currentTime, KeyEntry* entry,
DropReason* dropReason, nsecs_t* nextWakeupTime) {
...
Vector<InputTarget> inputTargets;
int32_t injectionResult = findFocusedWindowTargetsLocked(currentTime,
entry, inputTargets, nextWakeupTime); //1
if (injectionResult == INPUT_EVENT_INJECTION_PENDING) {
return false;
}
...
addMonitoringTargetsLocked(inputTargets);//2
// Dispatch the key.
dispatchEventLocked(currentTime, entry, inputTargets); //3
}
dispatchKeyLocked在注释1处获取按键事情关于的Window窗口,在注释2处放入一个监听input通道,注释3处实践处理事情处。
在解说注释1处获取窗口逻辑前咱们先来看下咱们窗口是怎么传入到InputDispatcher目标中的以及InputChannel概念。
事情分发通道注册
在之前一篇文章解说Window体系的文章中讲过,咱们Window是在ViewRootImpl的setView办法中传入WMS的。
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
...
mInputChannel = new InputChannel();
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
getHostVisibility(), mDisplay.getDisplayId(),
mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
mAttachInfo.mOutsets, mInputChannel);
if (mInputChannel != null) {
mInputEventReceiver = new WindowInputEventReceiver(mInputChannel,Looper.myLooper());
}
}
mWindowSession是IWindowSession在app端的代理目标。实践履行的是Session类
frameworks\base\services\core\java\com\android\server\wm\Session.java
public int addToDisplay(IWindow window,...InputChannel outInputChannel) {
return mService.addWindow(this, window, seq, attrs, viewVisibility, displayId,
outContentInsets, outStableInsets, outOutsets, outInputChannel);
}
这儿的mService是WMS目标,重点记住终究一个参数outInputChannel
WMS:
public int addWindow(Session session, IWindow client...InputChannel outInputChannel) {
...
final WindowState win = new WindowState(this, session, client, token, parentWindow,
appOp[0], seq, attrs, viewVisibility, session.mUid,
session.mCanAddInternalSystemWindow);
...
win.openInputChannel(outInputChannel); //1
if (focusChanged) {
mInputMonitor.setInputFocusLw(mCurrentFocus, false /*updateInputWindows*/);//2
}
}
addWindow的注释1处调用WindowState翻开InputChannel通道,什么是InputChannel通道呢?
进入WindowState的openInputChannel看看:
void openInputChannel(InputChannel outInputChannel) {
...
String name = getName();
InputChannel[] inputChannels = InputChannel.openInputChannelPair(name);//1
mInputChannel = inputChannels[0];
mClientChannel = inputChannels[1];
mInputWindowHandle.inputChannel = inputChannels[0];
if (outInputChannel != null) {
mClientChannel.transferTo(outInputChannel);
mClientChannel.dispose();
mClientChannel = null;
}
...
mService.mInputManager.registerInputChannel(mInputChannel, mInputWindowHandle);//2
}
InputChannel.java:
public static InputChannel[] openInputChannelPair(String name) {
...
return nativeOpenInputChannelPair(name);
}
android_view_InputChannel.cpp:
static jobjectArray android_view_InputChannel_nativeOpenInputChannelPair(JNIEnv* env...) {
...
sp<InputChannel> serverChannel;
sp<InputChannel> clientChannel;
status_t result = InputChannel::openInputChannelPair(name, serverChannel, clientChannel);
jobjectArray channelPair = env->NewObjectArray(2, gInputChannelClassInfo.clazz, NULL);
jobject serverChannelObj = android_view_InputChannel_createInputChannel(env,
std::make_unique<NativeInputChannel>(serverChannel));
jobject clientChannelObj = android_view_InputChannel_createInputChannel(env,
std::make_unique<NativeInputChannel>(clientChannel));
...
env->SetObjectArrayElement(channelPair, 0, serverChannelObj);
env->SetObjectArrayElement(channelPair, 1, clientChannelObj);
return channelPair;
}
status_t InputChannel::openInputChannelPair(const String8& name,
sp<InputChannel>& outServerChannel, sp<InputChannel>& outClientChannel) {
int sockets[2];
if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets)) {
...
return result;
}
...
outServerChannel = new InputChannel(serverChannelName, sockets[0]);
outClientChannel = new InputChannel(clientChannelName, sockets[1]);
return OK;
}
经过以上代码能够看出InputChannel运用的是sockets通讯,且WindowState的openInputChannel中注释1处:InputChannel[] inputChannels = InputChannel.openInputChannelPair(name),返回的inputChannels是一个服务端和客户端的输入通道数组 其间: 下标0:表明服务端的InputChannel 下标1:表明客户端的InputChannel
有了这些基础咱们再来细细品味下这段代码:为什么registerInputChannel传递的是mInputChannel而不是mClientChannel
void openInputChannel(InputChannel outInputChannel) {
...
String name = getName();
InputChannel[] inputChannels = InputChannel.openInputChannelPair(name);//1
mInputChannel = inputChannels[0];
mClientChannel = inputChannels[1];
mInputWindowHandle.inputChannel = inputChannels[0];
if (outInputChannel != null) {
mClientChannel.transferTo(outInputChannel);
mClientChannel.dispose();
mClientChannel = null;
}
...
mService.mInputManager.registerInputChannel(mInputChannel, mInputWindowHandle);//2
}
经过前面剖析知:
- mInputChannel:服务端的InputChannel
- mClientChannel:客户端的InputChannel
- outInputChannel:app层传递进来的InputChannel
Channel模型
-
1.调用mService.mInputManager.registerInputChannel 将wms在服务端的InputChannel注册到IMS中。这样在IMS输入体系就能够给服务端的InputChannel写入数据,在WMS的客户端InputChannel就能够读取数据
-
2.调用mClientChannel.transferTo(outInputChannel)
将app端的InputChannel和wms的客户端InputChannel相关 这样就能够向客户端InputChannel中写入数据然后告诉app端的InputChannel,实践传递给ViewRootImpl目标处理,接着便是View层面的处理了。
这儿咱们继续看注释2处:mService.mInputManager.registerInputChannel 终究会进入native层:
frameworks\base\services\core\jni\com_android_server_input_InputManagerService.cpp
static void nativeRegisterInputChannel(JNIEnv* env, jclass /* clazz */,
jlong ptr, jobject inputChannelObj, jobject inputWindowHandleObj, jboolean monitor) {
NativeInputManager* im = reinterpret_cast<NativeInputManager*>(ptr);
...
status_t status = im->registerInputChannel(
env, inputChannel, inputWindowHandle, monitor);//1
}
frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cpp
status_t NativeInputManager::registerInputChannel(JNIEnv* /* env */,
const sp<InputChannel>& inputChannel,
const sp<InputWindowHandle>& inputWindowHandle, bool monitor) {
return mInputManager->getDispatcher()->registerInputChannel(
inputChannel, inputWindowHandle, monitor);
}
frameworks/native/services/inputflinger/InputDispatcher.cpp
status_t InputDispatcher::registerInputChannel(const sp<InputChannel>& inputChannel,
const sp<InputWindowHandle>& inputWindowHandle, bool monitor) {
...
sp<Connection> connection = new Connection(inputChannel, inputWindowHandle, monitor);
int fd = inputChannel->getFd();
mConnectionsByFd.add(fd, connection);
...
// registerInputChannel里边传入的monitor是false --> nativeRegisterInputChannel(mPtr, inputChannel, inputWindowHandle, false);
// 所以这个流程不会将窗口的channel放到mMonitoringChannels里边
if (monitor) {
mMonitoringChannels.push(inputChannel);
}
...
}
im->registerInputChannel参数阐明:
- inputChannel:WMS在服务端InputChannel
- inputWindowHandle:WMS内的一个包括Window一切信息的实例。
- monitor:值为false,表明不加入监控
InputChannel时序图如下:
终究阶段在InputDispatcher中创立一个Connection并加入到mConnectionsByFd行列中,key为当时inputChannel的fd。获取的时分也是经过inputChannel的fd去获取
大约的通讯原理图如下:
经过上面的剖析咱们知道了,WMS和输入体系InputDispatcher运用的socket通讯,在View端,WMS端以及IMS端都有一个InputChannel。
哪个部分有数据需求分发便是将数据写入通道中。 那么接下来咱们看看IMS是怎么选取对应的通道的。
事情分发窗口承认
回到InputDispatcher::dispatchKeyLocked办法
bool InputDispatcher::dispatchKeyLocked(nsecs_t currentTime, KeyEntry* entry,
DropReason* dropReason, nsecs_t* nextWakeupTime) {
..
int32_t injectionResult = findFocusedWindowTargetsLocked(currentTime,
entry, inputTargets, nextWakeupTime); //1
dispatchEventLocked(currentTime, entry, inputTargets); //2
}
进入findFocusedWindowTargetsLocked:这个办法便是用来承认当时需求传递事情的窗口。
重点看inputTargets的赋值操作
int32_t InputDispatcher::findFocusedWindowTargetsLocked(...inputTargets){
...
addWindowTargetLocked(mFocusedWindowHandle,
InputTarget::FLAG_FOREGROUND | InputTarget::FLAG_DISPATCH_AS_IS, BitSet32(0),
inputTargets);
...
}
void InputDispatcher::addWindowTargetLocked(const sp<InputWindowHandle>& windowHandle,
int32_t targetFlags, BitSet32 pointerIds, Vector<InputTarget>& inputTargets) {
inputTargets.push();
const InputWindowInfo* windowInfo = windowHandle->getInfo();
InputTarget& target = inputTargets.editTop();
target.inputChannel = windowInfo->inputChannel;
target.flags = targetFlags;
target.xOffset = - windowInfo->frameLeft;
target.yOffset = - windowInfo->frameTop;
target.scaleFactor = windowInfo->scaleFactor;
target.pointerIds = pointerIds;
}
这儿能够看出findFocusedWindowTargetsLocked办法中对inputTargets的头部数据进行了赋值 其间将windowInfo->inputChannel通道赋值给了target.inputChannel。 那么这个windowInfo是个什么?怎么获取?
windowInfo是InputWindowHandle的属性,而InputWindowHandle传入的是一个mFocusedWindowHandle目标。 从名字也能够大约看出这是一个包括焦点Window信息的目标。
那么这个焦点Window是在哪里赋值的呢?
事情分发窗口注册
咱们回到WMS的addWindow进程。
// frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java
@Override
public int addWindow(Session session, IWindow client, int seq,
WindowManager.LayoutParams attrs, int viewVisibility, int displayId,
Rect outContentInsets, Rect outStableInsets, Rect outOutsets,
InputChannel outInputChannel) {
...
if (focusChanged) {
mInputMonitor.setInputFocusLw(mCurrentFocus, false /*updateInputWindows*/);
}
mInputMonitor.updateInputWindowsLw(false /*force*/);
...
}
在焦点产生改动的时分会调用setInputFocusLw办法和updateInputWindowsLw updateInputWindowsLw经过层层调用终究会走到InputDispatcher::setInputWindows中
// frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::setInputWindows(const Vector<sp<InputWindowHandle> >& inputWindowHandles) {
...
mWindowHandles = inputWindowHandles;
sp<InputWindowHandle> newFocusedWindowHandle;
...
for (size_t i = 0; i < mWindowHandles.size(); i++) {
const sp<InputWindowHandle>& windowHandle = mWindowHandles.itemAt(i);
...
if (windowHandle->getInfo()->hasFocus) {
newFocusedWindowHandle = windowHandle;
}
...
mFocusedWindowHandle = newFocusedWindowHandle;
}
...
}
看到了这儿对mWindowHandles和mFocusedWindowHandle做了赋值。
- mWindowHandles:代表一切Window的Handler目标
- mFocusedWindowHandle:表明焦点Window的Handler目标 经过这些代码就让咱们IMS中获取到了需求处理的焦点Window。
window窗口赋值时序图如下:
事情分发终究处理
继续回到回到InputDispatcher::dispatchKeyLocked办法的注释2
dispatchEventLocked(currentTime, entry, inputTargets); //2
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);
}
...
}
}
ssize_t InputDispatcher::getConnectionIndexLocked(const sp<InputChannel>& inputChannel) {
ssize_t connectionIndex = mConnectionsByFd.indexOfKey(inputChannel->getFd());
if (connectionIndex >= 0) {
sp<Connection> connection = mConnectionsByFd.valueAt(connectionIndex);
if (connection->inputChannel.get() == inputChannel.get()) {
return connectionIndex;
}
}
return -1;
}
dispatchEventLocked首要效果:轮询inputTargets,依据inputTarget.inputChannel获取其在mConnectionsByFd中的索引,依据索引获取Connection目标,并调用prepareDispatchCycleLocked进行处理。 prepareDispatchCycleLocked办法内部调用了enqueueDispatchEntriesLocked办法
void InputDispatcher::enqueueDispatchEntriesLocked(connection,..){
// Enqueue dispatch entries for the requested modes.
enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,...);//1
...
// If the outbound queue was previously empty, start the dispatch cycle going.
if (wasEmpty && !connection->outboundQueue.isEmpty()) {//2
startDispatchCycleLocked(currentTime, connection);//3
}
}
void InputDispatcher::enqueueDispatchEntryLocked(
const sp<Connection>& connection, EventEntry* eventEntry, const InputTarget* inputTarget,
int32_t dispatchMode) {
...
DispatchEntry* dispatchEntry = new DispatchEntry(eventEntry,
inputTargetFlags, inputTarget->xOffset, inputTarget->yOffset,
inputTarget->scaleFactor);
switch (eventEntry->type) {
case EventEntry::TYPE_KEY: {
KeyEntry* keyEntry = static_cast<KeyEntry*>(eventEntry);
dispatchEntry->resolvedAction = keyEntry->action;
dispatchEntry->resolvedFlags = keyEntry->flags;
...
break;
}
...
}
...
connection->outboundQueue.enqueueAtTail(dispatchEntry);
...
}
在注释1处enqueueDispatchEntryLocked办法中会将输入事情重新封装为一个DispatchEntry并压入connection的outboundQueue行列中。 然后在注释2处判别假如事情不为空,则调用startDispatchCycleLocked循环发送输入事情。
void InputDispatcher::startDispatchCycleLocked(nsecs_t currentTime,
const sp<Connection>& connection) {
while (connection->status == Connection::STATUS_NORMAL
&& !connection->outboundQueue.isEmpty()) {
DispatchEntry* dispatchEntry = connection->outboundQueue.head;
...
EventEntry* eventEntry = dispatchEntry->eventEntry;
switch (eventEntry->type) {
case EventEntry::TYPE_KEY: {
KeyEntry* keyEntry = static_cast<KeyEntry*>(eventEntry);
// Publish the key event.
status = connection->inputPublisher.publishKeyEvent(dispatchEntry->seq,
keyEntry->deviceId, keyEntry->source,
dispatchEntry->resolvedAction, dispatchEntry->resolvedFlags,
keyEntry->keyCode, keyEntry->scanCode,
keyEntry->metaState, keyEntry->repeatCount, keyEntry->downTime,
keyEntry->eventTime);
break;
}
...
connection->outboundQueue.dequeue(dispatchEntry);
connection->waitQueue.enqueueAtTail(dispatchEntry)
}
...
}
startDispatchCycleLocked办法中调用publishKeyEvent,其内部会将事情写入到WMS传递下来的InputChannel通道中。这样WMS端的InputChannel就能够经过socket获取到事情信息。在发送结束后会将事情移出connection->outboundQueue行列,并放入到waitQueue等候行列中,等候事情处理结束后再移出
waitQueue用来监听当时分发给WMS的输入事情是否现已被处理结束。什么时分知道事情处理结束呢?
在InputDispatcher::registerInputChannel办法里边注册了handleReceiveCallback回调:
status_t InputDispatcher::registerInputChannel(...) {
...
mLooper->addFd(fd, 0, ALOOPER_EVENT_INPUT, handleReceiveCallback, this);
...
}
当app层的事情处理结束之后就会回调handleReceiveCallback
int InputDispatcher::handleReceiveCallback(int fd, int events, void* data) {
InputDispatcher* d = static_cast<InputDispatcher*>(data);
...
d->finishDispatchCycleLocked(currentTime, connection, seq, handled);
...
d->runCommandsLockedInterruptible();
...
}
这儿会先调用InputDispatcher::finishDispatchCycleLocked去往mCommandQueue里边加入一个履行InputDispatcher:: doDispatchCycleFinishedLockedInterruptible的Command:
void InputDispatcher::doDispatchCycleFinishedLockedInterruptible(
CommandEntry* commandEntry) {
sp<Connection> connection = commandEntry->connection;
...
DispatchEntry* dispatchEntry = connection->findWaitQueueEntry(seq);
...
if (dispatchEntry == connection->findWaitQueueEntry(seq)) {
connection->waitQueue.dequeue(dispatchEntry);
...
}
}
doDispatchCycleFinishedLockedInterruptible中会将connection->waitQueue出栈,这样整个输入体系的分发进程就闭环了。
事情分发流程小结
下面对流程做一个总结:
- 1.ViewRootImpl在setView办法会创立一个InputChannel通道,并在将Window增加给WMS的进程时,以参数传递给WMS。
- 2.WMS在增加Window的进程中会调用updateInputWindows,这个办法终究会调用到InputDispatcher::setInputWindows中, 并给InputDispatcher的Window行列以及焦点Window赋值,这样IMS就能够找到对应的Window了
- 3.在WMS在增加Window的进程中还会创立一个socketpair通道的InputChannel,其间客户端的socket与app层的InputChannel相关,用于WMS与app通讯 服务端的socket传递给IMS,用于IMS和WMS通讯。
- 4.客户端在接收到输入事情后,会依据当时焦点Window的的InputChannel找到对应的Connection衔接,这个Connection用于与WMS进行通讯,内部其实便是运用前面的socket通讯。
- 5.事情分发后将输入事情放入到waitQueue中,等候事情处理结束后,将事情移出waitQueue
问题复盘
那么关于最初的两个问题:
-
问题1:窗口什么时分传入IMS输入体系的?IMS又是怎么找到对应的Window窗口的? ViewRootImpl在setView办法中,调用addToDisplay将Window传递给WMS的时分,这个时分会调用InputMonitor.updateInputWindowsLw办法,终究会调用到InputDispatcher::setInputWindows,这儿面会对IMS的WIndow属性进行赋值。IMS依据前面赋值的Window属性,就能够找到对应的焦点Window
-
问题2:IMS和WMS是经过什么方式通讯将事情分发出去的?
IMS和WMS是经过InputChannel通道进行通讯的,WMS在Window增加进程中会创立一个socket通道,将server端通道传递给IMS,而client端通道用于WMS中接收server端事情,server端依据对应的Window,找到对应的Connection,然后运用Connection进行通讯,而Connection内部便是经过socket进行通讯的
总结
因为篇幅问题,且大部分都是源码性质的,所以关于Android输入事情传递的进程运用了两篇文章来总结。
“framework必会”系列:Android Input体系(一)事情读取机制
“framework必会”系列:Android Input体系(二)事情分发机制
关于事情在View的传递进程相信咱们都比较清楚,这儿不在描绘了。
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