UI主线程监听socket客户端
WindowState.java
registerInputChannel
InputManagerService.java
updateInputWindowsLw
binder
启动looper循环监听epoll，让inputDispatcher监听服务端，有消息时则进行回调
nativeRegisterInputChannel
openInputChannelPair
com_android_server_input_InputManagerService.cpp
updateFocusedWindowLocked
更新窗口
创建WindowInputEventReceiver
addView
android_view_InputChannel.cpp
addWinodw
addToDisplay
传递保存inputChannel
WindowManagerGlobal.java
InputChannel.java
[Activitiy.java]onCreate()多级调用
root.setView
InputDispatcher.cpp
调用IMS注册监听服务端
创建成功，返回
这里对应着InputDispatcher中寻找聚焦窗口的命令findFocusedWindowTargetsLocked
更新聚焦窗口
ViewRootImpl.java
JNI
InputTransport.cpp
nativeOpenInputChannelPair
transferTo
WindowManagerService.java
InputMonitor.java
win.openInputChannel
