Touch Event Dispatch Procedure in Android 10

触摸事件只会分发给可见的能够接受事件的窗口

在P版本上相关的成员
ViewRootImpl
WindowManagerService
InputDispatcher

Q版本相关的成员
ViewRootImpl
WindowManagerService
SurfaceFlinger
InputDispatcher

当前窗口在执行完onResume后由框架向WindowManagerService添加窗口，并开始接收Input事件

ActivityThread.java
wm.addView(decor, l);
ViewRootImpl.java
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
        getHostVisibility(), mDisplay.getDisplayId(), mTmpFrame,
        mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
        mAttachInfo.mOutsets, mAttachInfo.mDisplayCutout, mInputChannel,
        mTempInsets);
mInputEventReceiver = new WindowInputEventReceiver(mInputChannel,
        Looper.myLooper());

WindowManagerService添加窗口
打开InputChannel
更新焦点窗口
更新Input窗口

final boolean openInputChannels = (outInputChannel != null
        && (attrs.inputFeatures & INPUT_FEATURE_NO_INPUT_CHANNEL) == 0);
if  (openInputChannels) {
    win.openInputChannel(outInputChannel);
}
boolean focusChanged = false;
if (win.canReceiveKeys()) {
    focusChanged = updateFocusedWindowLocked(UPDATE_FOCUS_WILL_ASSIGN_LAYERS,
            false /*updateInputWindows*/);
    if (focusChanged) {
        imMayMove = false;
    }
}
if (focusChanged) {
    displayContent.getInputMonitor().setInputFocusLw(displayContent.mCurrentFocus,
            false /*updateInputWindows*/);
}
displayContent.getInputMonitor().updateInputWindowsLw(false /*force*/);

焦点窗口被设置到SurfaceFlinger

// DisplayContent.java
int focusChanged = getDisplayPolicy().focusChangedLw(oldFocus, newFocus);
// InputMonitor.java
void updateInputWindowsLw(boolean force) {
    if (!force && !mUpdateInputWindowsNeeded) {
        return;
    }
    scheduleUpdateInputWindows();
}
mUpdateInputForAllWindowsConsumer.updateInputWindows(inDrag);
// 不更新的场景
if (inputChannel == null || inputWindowHandle == null || w.mRemoved
        || w.cantReceiveTouchInput()) {
    if (w.mWinAnimator.hasSurface()) {
        mInputTransaction.setInputWindowInfo(
                w.mWinAnimator.mSurfaceController.mSurfaceControl, mInvalidInputWindow);
    }
    // Skip this window because it cannot possibly receive input.
    return;
}
// 更新的场景
populateInputWindowHandle(
        inputWindowHandle, w, flags, type, isVisible, hasFocus, hasWallpaper);
if (w.mWinAnimator.hasSurface()) {
    mInputTransaction.setInputWindowInfo(
            w.mWinAnimator.mSurfaceController.mSurfaceControl, inputWindowHandle);
}
// android_view_SurfaceControl.cpp
static void nativeSetInputWindowInfo(JNIEnv* env, jclass clazz, jlong transactionObj,
        jlong nativeObject, jobject inputWindow) {
    auto transaction = reinterpret_cast<SurfaceComposerClient::Transaction*>(transactionObj);
    sp<NativeInputWindowHandle> handle = android_view_InputWindowHandle_getHandle(
            env, inputWindow);
    handle->updateInfo();
    SurfaceControl* const ctrl = reinterpret_cast<SurfaceControl *>(nativeObject);
    transaction->setInputWindowInfo(ctrl, *handle->getInfo());
}

SurfaceFlinger设置可以接收事件的窗口到InputDispatcher

void SurfaceFlinger::updateInputWindowInfo() {
    std::vector<InputWindowInfo> inputHandles;
    mDrawingState.traverseInReverseZOrder([&](Layer* layer) {
        if (layer->hasInput()) {
            // When calculating the screen bounds we ignore the transparent region since it may
            // result in an unwanted offset.
            inputHandles.push_back(layer->fillInputInfo());
        }
    });
    mInputFlinger->setInputWindows(inputHandles,
                                   mInputWindowCommands.syncInputWindows ? mSetInputWindowsListener
                                                                         : nullptr);
}

InputDispatcher根据InputWIndowHandle的属性更新分发窗口

MapleStory

Touch Event Dispatch Procedure in Android 10

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