页面比较

InputMethodService:    at android.inputmethodservice.InputMethodService.lambda$new$0$InputMethodService(InputMethodService.java:501)
InputMethodService:    at android.inputmethodservice.-$$Lambda$InputMethodService$8T9TmAUIN7vW9eU6kTg8309_d4E.onComputeInternalInsets(Unknown Source:2)
InputMethodService:    at android.view.ViewTreeObserver.dispatchOnComputeInternalInsets(ViewTreeObserver.java:1203)
InputMethodService:    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2994)
InputMethodService:    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1948)
InputMethodService:    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8177)
InputMethodService:    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:972)
InputMethodService:    at android.view.Choreographer.doCallbacks(Choreographer.java:796)
InputMethodService:    at android.view.Choreographer.doFrame(Choreographer.java:731)
InputMethodService:    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:957)
InputMethodService:    at android.os.Handler.handleCallback(Handler.java:938)
InputMethodService:    at android.os.Handler.dispatchMessage(Handler.java:99)
InputMethodService:    at android.os.Looper.loop(Looper.java:223)
InputMethodService:    at android.app.ActivityThread.main(ActivityThread.java:7665)
InputMethodService:    at java.lang.reflect.Method.invoke(Native Method)
InputMethodService:    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
InputMethodService:    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:948)



InputMethodService类
onCreate()->initViews(){
......
mRootView.getViewTreeObserver().addOnComputeInternalInsetsListener(mInsetsComputer);//添加内部嵌入块大小计算的监听回调
......
}

final ViewTreeObserver.OnComputeInternalInsetsListener mInsetsComputer = info -> {  //这里是一个lambda表达式，info的类型是InternalInsetsInfo，响应前面添加的OnComputeInternalInsetsListener监听回调onComputeInternalInsets。
        onComputeInsets(mTmpInsets);
......
//将计算后的插入块内容区和可见区的top值回传给ViewRootImpl进行遍历计算。这个地方是导致WPS拉起输入法白屏显示的关键逻辑。
//异常时两个值均为0，即认为content内容区全部被软键盘遮挡所以白屏不显示任何内容。正常显示输入法软键盘时的值是软键盘上方边缘（top）的Y值。这里直接使用输入法软键盘根view的整个高度作为软键盘可见top值实现对应用内容区的零遮挡。
info.contentInsets.top = rootView.getHeight();//mTmpInsets.contentTopInsets;
info.visibleInsets.top = rootView.getHeight();//mTmpInsets.visibleTopInsets;
......
}



Choreographer类
Choreographer::FrameDisplayEventReceiver类
收到刷新信号后执行run方法
@Override
public void run() {
mHavePendingVsync = false;
doFrame(mTimestampNanos, mFrame);
}

doFrame(...)->doCallbacks(...)
     
doCallbacks(...){
......
for (CallbackRecord c = callbacks; c != null; c = c.next) {
......
c.run(frameTimeNanos);//会调用到ViewRootImpl类对象通过mChoreographer.postCallback传过来的mTraversalRunnable
}
......
}

ViewRootImpl的TraversalRunnable内部类
final class TraversalRunnable implements Runnable {
@Override
public void run() {
doTraversal();
}
}
ViewRootImpl类
final TraversalRunnable mTraversalRunnable = new TraversalRunnable();
void scheduleTraversals() {
if (!mTraversalScheduled) {
mTraversalScheduled = true;
mTraversalBarrier = mHandler.getLooper().getQueue().postSyncBarrier();
mChoreographer.postCallback(
Choreographer.CALLBACK_TRAVERSAL, mTraversalRunnable, null);
notifyRendererOfFramePending();
pokeDrawLockIfNeeded();
}
}

final boolean computesInternalInsets =
                mAttachInfo.mTreeObserver.hasComputeInternalInsetsListeners()
                || mAttachInfo.mHasNonEmptyGivenInternalInsets;

TraversalRunnable类对象执行run方法调到doTraversal执行遍历操作
ViewRootImpl->doTraversal(...)->performTraversals(...){
......
if (computesInternalInsets) {
// Clear the original insets.
final ViewTreeObserver.InternalInsetsInfo insets = mAttachInfo.mGivenInternalInsets;
insets.reset();

// Compute new insets in place.
mAttachInfo.mTreeObserver.dispatchOnComputeInternalInsets(insets);
......
}
......
}

ViewTreeObserver类
final void dispatchOnComputeInternalInsets(InternalInsetsInfo inoutInfo) {
        final CopyOnWriteArray<OnComputeInternalInsetsListener> listeners =
                mOnComputeInternalInsetsListeners;
        if (listeners != null && listeners.size() > 0) {
            CopyOnWriteArray.Access<OnComputeInternalInsetsListener> access = listeners.start();
            try {
                int count = access.size();
                for (int i = 0; i < count; i++) {
                    access.get(i).onComputeInternalInsets(inoutInfo);
                }
            } finally {
                listeners.end();
            }
        }
    }
//通过onComputeInternalInsets回调（最前面InputMethodService在initViews注册了此监听），从InputMethodService得到软键盘的可见top值visibleTopInsets后，ViewRootImpl再执行performTraversals遍历更新应用的内容区的后续逻辑。