frameworks 之 触摸事件窗口查找

触摸流程中最重要的流程之一就是查找需要传递输入事件的窗口，并将触摸事件传递下去。
涉及到的类如下

• frameworks/native/services/inputflinger/dispatcher/InputDispatcher.cpp

上文讲到 进行 dispatchMotionLocked 后，会通过 findTouchedWindowTargetsLocked 进行窗口查找

1. 初始化数据

1. 会将当前数据复制到 tempTouchState 数据中。
2. 获取当前是否分屏保存到 isSplit
3. 判断是否触摸是否切换了设备，保存在 switchedDevice 变量
4. 判断是否第一个手指按下 保存在 newGesture 变量

InputEventInjectionResult InputDispatcher::findTouchedWindowTargetsLocked(nsecs_t currentTime, const MotionEntry& entry, std::vector<InputTarget>& inputTargets,nsecs_t* nextWakeupTime, bool* outConflictingPointerActions) {...const TouchState* oldState = nullptr;TouchState tempTouchState;std::unordered_map<int32_t, TouchState>::iterator oldStateIt =mTouchStatesByDisplay.find(displayId);if (oldStateIt != mTouchStatesByDisplay.end()) {oldState = &(oldStateIt->second);tempTouchState.copyFrom(*oldState);}// 代表是否支持分屏bool isSplit = tempTouchState.split;// 是否切换输入设备 比如注入事件 然后手指按下bool switchedDevice = tempTouchState.deviceId >= 0 && tempTouchState.displayId >= 0 &&(tempTouchState.deviceId != entry.deviceId || tempTouchState.source != entry.source ||tempTouchState.displayId != displayId);bool isHoverAction = (maskedAction == AMOTION_EVENT_ACTION_HOVER_MOVE ||maskedAction == AMOTION_EVENT_ACTION_HOVER_ENTER ||maskedAction == AMOTION_EVENT_ACTION_HOVER_EXIT);// 是否第一个手指按下bool newGesture = (maskedAction == AMOTION_EVENT_ACTION_DOWN ||maskedAction == AMOTION_EVENT_ACTION_SCROLL || isHoverAction);}

2. 查找窗口

通过 findTouchedWindowAtLocked 获取对应的 WindowInfoHandle 。、

1. 根据 displayId 通过 getWindowHandlesLocked 方法获取对应的 WindowInfoHandle 集合，该集合通过 Surfaceflings*刷新的时候 添加。
2. 获取后进行遍历，首先判断 displayId是否一样，一样才进入判断。
3. 判断window 是否可见
4. 接着判断 window 是否没带 NOT_TOUCHABLE 的 flag，如果带了则过滤了该窗口。
5. 判断窗口是否聚焦 并且 不带 NOT_TOUCH_MODAL （表示窗口聚焦的时候，设置了该 flag 不能将事件传递给外部窗口，反之没设置则可以），如果可以传递 或在触摸的 坐标在 窗口内则是该窗口
6. 最后还需判断该窗口是否 投屏窗口 如果是的话 则需要递归传入投屏的displayId 进行查找在返回，否则返回该窗口。
7. 还有判断是否带有 WATCH_OUTSIDE_TOUCH 的 flag，如果为支持外部触碰则也通过 addOrUpdateWindow 添加到 touchState

// 查找对应的可触摸window
sp<WindowInfoHandle> InputDispatcher::findTouchedWindowAtLocked(int32_t displayId, int32_t x,int32_t y, TouchState* touchState,bool addOutsideTargets,bool addPortalWindows,bool ignoreDragWindow) {if ((addPortalWindows || addOutsideTargets) && touchState == nullptr) {LOG_ALWAYS_FATAL("Must provide a valid touch state if adding portal windows or outside targets");}// Traverse windows from front to back to find touched window.// 返回可见的window数组const std::vector<sp<WindowInfoHandle>>& windowHandles = getWindowHandlesLocked(displayId);for (const sp<WindowInfoHandle>& windowHandle : windowHandles) {if (ignoreDragWindow && haveSameToken(windowHandle, mDragState->dragWindow)) {continue;}const WindowInfo* windowInfo = windowHandle->getInfo();// 判断屏幕是否一样if (windowInfo->displayId == displayId) {auto flags = windowInfo->flags;// 是否可见if (windowInfo->visible) {// window的flag是否没设置不可触摸if (!flags.test(WindowInfo::Flag::NOT_TOUCHABLE)) {// FLAG_NOT_TOUCH_MODAL 非模态对话框 表示即使window是处于上面的默认状态下，设置了该Flag，// 新window范围外的view也是可以响应touch事件。是模态的话 该范围外的 不可响应对应的事件bool isTouchModal = !flags.test(WindowInfo::Flag::NOT_FOCUSABLE) &&!flags.test(WindowInfo::Flag::NOT_TOUCH_MODAL);// 触摸是否包含在对应的window内，或者窗口是虚拟屏if (isTouchModal || windowInfo->touchableRegionContainsPoint(x, y)) {int32_t portalToDisplayId = windowInfo->portalToDisplayId;if (portalToDisplayId != ADISPLAY_ID_NONE &&portalToDisplayId != displayId) {if (addPortalWindows) {// For the monitoring channels of the display.touchState->addPortalWindow(windowHandle);}// 不相等则调用方法查找，但是查找的是对应的displayIdreturn findTouchedWindowAtLocked(portalToDisplayId, x, y, touchState,addOutsideTargets, addPortalWindows);}// Found window.return windowHandle;}}// 是否外部可点击if (addOutsideTargets && flags.test(WindowInfo::Flag::WATCH_OUTSIDE_TOUCH)) {touchState->addOrUpdateWindow(windowHandle,InputTarget::FLAG_DISPATCH_AS_OUTSIDE,BitSet32(0));}}}}return nullptr;
}

3. 分屏处理

1. 会判断是否第一次触摸 或者 表示上一次触摸的窗口支持分屏，并且这次事件是按下事件
2. 通过 findTouchedWindowAtLocked 获取对应的 WindowInfoHandle 上面已经讲解
3. 如果查找不为空，判断窗口是否允许分屏,并赋值给 isSplit ，如果 是鼠标事件一定不支持。
4. 因为上一次的支持分屏，但是新的窗口不支持分屏，将查找到的windowHandle置为空,忽略此次窗口
5. 接下来都是判断一些窗口连接是否在，是否需要抛弃此次事件等判断，将 windowHandle 置为空
6. 如果新窗口，并且手指监听也为空，则进入失败代码逻辑
7. 如果窗口不为空，则添加 各种 flag 如 FLAG_FOREGROUND，FLAG_DISPATCH_AS_IS，最后 也是通过 tempTouchState.addOrUpdateWindow 添加到 tempTouchState。

	// 第一个条件 newGesture 表示第一个手指按下// 后面一个条件，表示当前窗口支持 split motion，并且此时有另外一个手指按下if (newGesture || (isSplit && maskedAction == AMOTION_EVENT_ACTION_POINTER_DOWN)) {/* Case 1: New splittable pointer going down, or need target for hover or scroll. */int32_t x;int32_t y;int32_t pointerIndex = getMotionEventActionPointerIndex(action);// Always dispatch mouse events to cursor position.// 是否鼠标对xy进行修正if (isFromMouse) {x = int32_t(entry.xCursorPosition);y = int32_t(entry.yCursorPosition);} else {x = int32_t(entry.pointerCoords[pointerIndex].getAxisValue(AMOTION_EVENT_AXIS_X));y = int32_t(entry.pointerCoords[pointerIndex].getAxisValue(AMOTION_EVENT_AXIS_Y));}// 这里检测是否是第一个手指按下bool isDown = maskedAction == AMOTION_EVENT_ACTION_DOWN;newTouchedWindowHandle =findTouchedWindowAtLocked(displayId, x, y, &tempTouchState,isDown /*addOutsideTargets*/, true /*addPortalWindows*/);// Figure out whether splitting will be allowed for this window.// 判断新窗口是否允许分屏操作if (newTouchedWindowHandle != nullptr &&newTouchedWindowHandle->getInfo()->supportsSplitTouch()) {// New window supports splitting, but we should never split mouse events.// 如果是鼠标事件一定不支持分屏isSplit = !isFromMouse;} else if (isSplit) {// New window does not support splitting but we have already split events.// Ignore the new window.// 因为上一次的支持分屏，但是新的窗口不支持分屏，将查找到的windowHandle置为空,忽略此次窗口newTouchedWindowHandle = nullptr;}// Handle the case where we did not find a window.if (newTouchedWindowHandle == nullptr) {// Try to assign the pointer to the first foreground window we find, if there is one.newTouchedWindowHandle = tempTouchState.getFirstForegroundWindowHandle();}if (newTouchedWindowHandle != nullptr && newTouchedWindowHandle->getInfo()->paused) {ALOGI("Not sending touch event to %s because it is paused",newTouchedWindowHandle->getName().c_str());newTouchedWindowHandle = nullptr;}// Ensure the window has a connection and the connection is responsiveif (newTouchedWindowHandle != nullptr) {const bool isResponsive = hasResponsiveConnectionLocked(*newTouchedWindowHandle);if (!isResponsive) {ALOGW("%s will not receive the new gesture at %" PRIu64,newTouchedWindowHandle->getName().c_str(), entry.eventTime);newTouchedWindowHandle = nullptr;}}// Drop events that can't be trusted due to occlusionif (newTouchedWindowHandle != nullptr &&mBlockUntrustedTouchesMode != BlockUntrustedTouchesMode::DISABLED) {TouchOcclusionInfo occlusionInfo =computeTouchOcclusionInfoLocked(newTouchedWindowHandle, x, y);if (!isTouchTrustedLocked(occlusionInfo)) {if (DEBUG_TOUCH_OCCLUSION) {ALOGD("Stack of obscuring windows during untrusted touch (%d, %d):", x, y);for (const auto& log : occlusionInfo.debugInfo) {ALOGD("%s", log.c_str());}}onUntrustedTouchLocked(occlusionInfo.obscuringPackage);if (mBlockUntrustedTouchesMode == BlockUntrustedTouchesMode::BLOCK) {ALOGW("Dropping untrusted touch event due to %s/%d",occlusionInfo.obscuringPackage.c_str(), occlusionInfo.obscuringUid);newTouchedWindowHandle = nullptr;}}}// Drop touch events if requested by input featureif (newTouchedWindowHandle != nullptr && shouldDropInput(entry, newTouchedWindowHandle)) {newTouchedWindowHandle = nullptr;}const std::vector<TouchedMonitor> newGestureMonitors = isDown? selectResponsiveMonitorsLocked(findTouchedGestureMonitorsLocked(displayId, tempTouchState.portalWindows)): tempTouchState.gestureMonitors;// 如果新窗口，并且手指监听也为空，则进入失败代码逻辑if (newTouchedWindowHandle == nullptr && newGestureMonitors.empty()) {ALOGI("Dropping event because there is no touchable window or gesture monitor at ""(%d, %d) in display %" PRId32 ".",x, y, displayId);injectionResult = InputEventInjectionResult::FAILED;goto Failed;}if (newTouchedWindowHandle != nullptr) {// Set target flags.// 标记为前段可触摸int32_t targetFlags = InputTarget::FLAG_FOREGROUND | InputTarget::FLAG_DISPATCH_AS_IS;// 是否可分离if (isSplit) {targetFlags |= InputTarget::FLAG_SPLIT;}// 是不是被人覆盖if (isWindowObscuredAtPointLocked(newTouchedWindowHandle, x, y)) {targetFlags |= InputTarget::FLAG_WINDOW_IS_OBSCURED;} else if (isWindowObscuredLocked(newTouchedWindowHandle)) {targetFlags |= InputTarget::FLAG_WINDOW_IS_PARTIALLY_OBSCURED;}// Update hover state.if (maskedAction == AMOTION_EVENT_ACTION_HOVER_EXIT) {newHoverWindowHandle = nullptr;} else if (isHoverAction) {newHoverWindowHandle = newTouchedWindowHandle;}// Update the temporary touch state.BitSet32 pointerIds;if (isSplit) {uint32_t pointerId = entry.pointerProperties[pointerIndex].id;pointerIds.markBit(pointerId);}// 添加到touchStatetempTouchState.addOrUpdateWindow(newTouchedWindowHandle, targetFlags, pointerIds);} else if (tempTouchState.windows.empty()) {// If no window is touched, set split to true. This will allow the next pointer down to// be delivered to a new window which supports split touch.tempTouchState.split = true;}if (isDown) {tempTouchState.addGestureMonitors(newGestureMonitors);}}

else 部分 是判断 move 事件 的查找。主要判断是否允许事件滑动到其他窗口 如 toast

4. 检查对应的权限

1. 开始和i遍历里面的window 判断 flag 是否在前台
2. 通过 checkInjectionPermission 判断权限，非系统应用，只能事件注入在自己应用。
3. 遍历完如果又没前台窗口，全局手势也为空，则跳转失败处理

// Check permission to inject into all touched foreground windows and ensure there// is at least one touched foreground window.{bool haveForegroundWindow = false;for (const TouchedWindow& touchedWindow : tempTouchState.windows) {if (touchedWindow.targetFlags & InputTarget::FLAG_FOREGROUND) {// 是否前台haveForegroundWindow = true;// 检查权限 注入事件只能在自己应用 除非其他系统权限if (!checkInjectionPermission(touchedWindow.windowHandle, entry.injectionState)) {injectionResult = InputEventInjectionResult::PERMISSION_DENIED;injectionPermission = INJECTION_PERMISSION_DENIED;goto Failed;}}}// 如果又没前台窗口，全局手势也为空，则跳转失败处理bool hasGestureMonitor = !tempTouchState.gestureMonitors.empty();if (!haveForegroundWindow && !hasGestureMonitor) {ALOGI("Dropping event because there is no touched foreground window in display ""%" PRId32 " or gesture monitor to receive it.",displayId);injectionResult = InputEventInjectionResult::FAILED;goto Failed;}// Permission granted to injection into all touched foreground windows.injectionPermission = INJECTION_PERMISSION_GRANTED;}

5.是否需要将事件传递给壁纸界面

判断当前前台的窗口是否带 hasWallpaper 属性，如果是的话 则遍历对应 windowHandles 集合，如果对应的 displayId一样并且 type为 WindowInfo::Type::WALLPAPER。则添加进行。这就是为啥触摸桌面，壁纸也会动。

// 是否带壁纸属性，如果是则找到壁纸的window 事件传递给他.如桌面if (maskedAction == AMOTION_EVENT_ACTION_DOWN) {sp<WindowInfoHandle> foregroundWindowHandle =tempTouchState.getFirstForegroundWindowHandle();if (foregroundWindowHandle && foregroundWindowHandle->getInfo()->hasWallpaper) {const std::vector<sp<WindowInfoHandle>>& windowHandles =getWindowHandlesLocked(displayId);for (const sp<WindowInfoHandle>& windowHandle : windowHandles) {const WindowInfo* info = windowHandle->getInfo();if (info->displayId == displayId &&windowHandle->getInfo()->type == WindowInfo::Type::WALLPAPER) {tempTouchState.addOrUpdateWindow(windowHandle,InputTarget::FLAG_WINDOW_IS_OBSCURED |InputTarget::FLAG_WINDOW_IS_PARTIALLY_OBSCURED |InputTarget::FLAG_DISPATCH_AS_IS,BitSet32(0));}}}}

6. 成功处理

如果都ok的话 则分别将对应的window添加到 inputTager数组 和 全局 monitoringTarget 数组 返回结果

// Success!  Output targets.injectionResult = InputEventInjectionResult::SUCCEEDED;for (const TouchedWindow& touchedWindow : tempTouchState.windows) {// 添加到inputTarget里面addWindowTargetLocked(touchedWindow.windowHandle, touchedWindow.targetFlags,touchedWindow.pointerIds, inputTargets);}for (const TouchedMonitor& touchedMonitor : tempTouchState.gestureMonitors) {addMonitoringTargetLocked(touchedMonitor.monitor, touchedMonitor.xOffset,touchedMonitor.yOffset, inputTargets);}