if（mFDs[i].revents）{
LOGV（"reventsfor%d=0x%08x",i,mFDs[i].revents）;
if（mFDs[i].revents&POLLIN）{
res=read（mFDs[i].fd,&iev,sizeof（iev））;
if（res==sizeof（iev））{
LOGV（"%sgot:
t0=%d,t1=%d,type=%d,code=%d,v=%d",
mDevices[i]->path.string（）,
....
}
4.那么framework中那个模块再调用EventHub呢，接着往下查。
在framework目录中，输入下面的命令查找
#find.-name"*.cpp"|grep-vEventHub|xargsgrepEventHub
./base/services/jni/com_android_server_KeyInputQueue.cpp:
#include
./base/services/jni/com_android_server_KeyInputQueue.cpp:
staticspgHub;
./base/services/jni/com_android_server_KeyInputQueue.cpp:
sphub=gHub;
./base/services/jni/com_android_server_KeyInputQueue.cpp:
hub=newEventHub;
./base/services/jni/com_android_server_KeyInputQueue.cpp:
sphub=gHub;
./base/services/jni/com_android_server_KeyInputQueue.cpp:
hub=newEventHub;
5.从查找结果中得知，在jni文件com_android_server_KeyInputQueue.cpp文件中有对EventHub进行调用。
打开并阅读com_android_server_KeyInputQueue.cpp文件得知，在下面的函数中调用了EventHub的getEvent函数
staticjboolean
android_server_KeyInputQueue_readEvent（JNIEnv*env,jobjectclazz,
jobjectevent）
{
gLock.lock（）;
sphub=gHub;
if（hub==NULL）{
hub=newEventHub;
gHub=hub;
}
gLock.unlock（）;
int32_tdeviceId;
int32_ttype;
int32_tscancode,keycode;
uint32_tflags;
int32_tvalue;
nsecs_twhen;
boolres=hub->getEvent（&deviceId,&type,&scancode,&keycode,
&flags,&value,&when）;
env->SetIntField（event,gInputOffsets.mDeviceId,（jint）deviceId）;
env->SetIntField（event,gInputOffsets.mType,（jint）type）;
env->SetIntField（event,gInputOffsets.mScancode,（jint）scancode）;
env->SetIntField（event,gInputOffsets.mKeycode,（jint）keycode）;
env->SetIntField（event,gInputOffsets.mFlags,（jint）flags）;
env->SetIntField（event,gInputOffsets.mValue,value）;
env->SetLongField（event,gInputOffsets.mWhen,
（jlong）（nanoseconds_to_milliseconds（when）））;
returnres;
}
6.根据jni的调用规则，在本文件中查找对于的java函数。
staticJNINativeMethodgInputMethods[]={
/*name,signature,funcPtr*/
{"readEvent","（Landroid/view/RawInputEvent;）Z",
（void*）android_server_KeyInputQueue_readEvent},
....
7.接着顺藤摸瓜，找到对应的java文件,base/services/java/com/android/server/KeyInputQueue.java
privatestaticnativebooleanreadEvent（RawInputEventoutEvent）;
在一个线程中会调用readEvent函数。
ThreadmThread=newThread（"InputDeviceReader"）{
publicvoidrun（）{
if（DEBUG）Slog.v（TAG,"InputDeviceReader.run（）"）;
android.os.Process.setThreadPriority（
android.os.Process.THREAD_PRIORITY_URGENT_DISPLAY）;
RawInputEventev=newRawInputEvent（）;
while（true）{
try{
InputDevicedi;
//block,doesn'treleasethemonitor
readEvent（ev）;
booleansend=false;
booleanconfigChanged=false;
if（false）{
Slog.i（TAG,"Inputevent:
dev=0x"
+Integer.toHexString（ev.deviceId）
+"type=0x"+Integer.toHexString（ev.type）
+"scancode="+ev.scancode
+"keycode="+ev.keycode
+"value="+ev.value）;
}
8.那是谁启动这个线程呢？
？
？
查找mThread变量，得知在KeyInputQueue的构造函数中会启动这个线程。
KeyInputQueue（Contextcontext,HapticFeedbackCallbackhapticFeedbackCallback）{
if（MEASURE_LATENCY）{
lt=newLatencyTimer（100,1000）;
}
Resourcesr=context.getResources（）;
BAD_TOUCH_HACK=r.getBoolean（com.android.internal.R.bool.config_filterTouchEvents）;
JUMPY_TOUCH_HACK=r.getBoolean（com.android.internal.R.bool.config_filterJumpyTouchEvents）;
mHapticFeedbackCallback=hapticFeedbackCallback;
readExcludedDevices（）;
PowerManagerpm=（PowerManager）context.getSystemService（
Context.POWER_SERVICE）;
mWakeLock=pm.newWakeLock（PowerManager.PARTIAL_WAKE_LOCK,
"KeyInputQueue"）;
mWakeLock.setReferenceCounted（false）;
mFirst=newQueuedEvent（）;
mLast=newQueuedEvent（）;
mFirst.next=mLast;
mThread.start（）;
}
9.那这个KeyInputQueue是在哪里被实例化呢？
而且查看KeyInputQueue类的声明，得知它是一个abstractclass.
publicabstractclassKeyInputQueue
{
.....
}
说明它肯定会被某个类继承.接着查找。
/frameworks$find.-name"*.java"|grep-vKeyInputQueue|xargsgrepKeyInputQueue
./policies/base/phone/com/android/internal/policy/impl/KeyguardViewMediator.java:
*{@linkcom.android.server.KeyInputQueue}'sand{@linkandroid.view.WindowManager}'s.
./base/services/java/com/android/server/PowerManagerService.java:
&&!
"KeyInputQueue".equals（tag）））{
./base/services/java/com/android/server/WindowManagerService.java:
importcom.android.server.KeyInputQueue.QueuedEvent;
./base/services/java/com/android/server/WindowManagerService.java:
implementsWatchdog.Monitor,KeyInputQueue.HapticFeedbackCallback{
./base/services/java/com/android/server/WindowManagerService.java:
returnKeyInputQueue.getSwitchState（sw）;
./base/services/java/com/android/server/WindowManagerService.java:
returnKeyInputQueue.getSwitchState（devid,sw）;
./base/services/java/com/android/server/WindowManagerService.java:
returnKeyInputQueue.hasKeys（keycodes,keyExists）;
./base/services/java/com/android/server/WindowManagerService.java:
privateclassKeyQextendsKeyInputQueue
./base/services/java/com/android/server/WindowManagerService.java:
implementsKeyInputQueue.FilterCallback{
./base/services/java/com/android/server/InputDevice.java:
//ForusebyKeyInputQueueforkeepingtrackofthecurrenttouch
./base/services/java/com/android/server/InputDevice.java:
if（KeyInputQueue.BAD_TOUCH_HACK）{
./base/services/java/com/android/server/InputDevice.java:
Slog.i（"KeyInputQueue","Updating:
"+currentMove）;
./base/services/java/com/android/server/InputDevice.java:
Slog.i（"KeyInputQueue","Updating:
"+currentMove）;
10.从上面的查找结果得知，会在WindowManagerService.java中有一个KeyQ类继承KeyInputQueue类，再在这个文件中查找KeyQ类在哪里定义并实例化的，找到在其构造函数里实例化的。
privateWindowManagerService（Contextcontext,PowerManagerService
升级会员 