Android系统源码分析Input - InputReader读取事件

1. 我们已经知道在Input启动过程创建了InputReader线程。InputReader线程创建后会持续调用loopOnce。

// frameworks/native/services/inputflinger/reader/InputReader.cpp

status_t InputReader::start() {
    if (mThread) {
        return ALREADY_EXISTS;
    }
    
    mThread = std::make_unique<InputThread>(
            "InputReader", [this]() { loopOnce(); }, [this]() { mEventHub->wake(); });
    return OK;
}

2. 这里会调用mEventHub->getEvents从设备节点中获取一批RawEvent（原事件），并调用processEventsLocked将RawEvents封装成NotifyArgs，最后将NotifyArgs发送给InputDispacher。

// frameworks/native/services/inputflinger/reader/InputReader.cpp

void InputReader::loopOnce() {
    int32_t oldGeneration;
    int32_t timeoutMillis;
    bool inputDevicesChanged = false;
    std::vector<InputDeviceInfo> inputDevices;
    std::list<NotifyArgs> notifyArgs;
    { // acquire lock
        std::scoped_lock _l(mLock);

        oldGeneration = mGeneration;
        timeoutMillis = -1;

        // 如果需要，将刷新设备的配置
        auto changes = mConfigurationChangesToRefresh;
        if (changes.any()) {
            mConfigurationChangesToRefresh.clear();
            timeoutMillis = 0;
            refreshConfigurationLocked(changes);
        } else if (mNextTimeout != LLONG_MAX) {
            nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
            timeoutMillis = toMillisecondTimeoutDelay(now, mNextTimeout);
        }
    } // release lock

    // 通过EventHub从设备节点中读取RawEvent
    std::vector<RawEvent> events = mEventHub->getEvents(timeoutMillis);

    { // acquire lock
        std::scoped_lock _l(mLock);
        mReaderIsAliveCondition.notify_all();

        if (!events.empty()) {
            // 将RawEvents封装成PendingArgs
            mPendingArgs += processEventsLocked(events.data(), events.size());
        }

        if (mNextTimeout != LLONG_MAX) {
            nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
            if (now >= mNextTimeout) {
                if (debugRawEvents()) {
                    ALOGD("Timeout expired, latency=%0.3fms", (now - mNextTimeout) * 0.000001f);
                }
                mNextTimeout = LLONG_MAX;
                mPendingArgs += timeoutExpiredLocked(now);
            }
        }

        if (oldGeneration != mGeneration) {
            inputDevicesChanged = true;
            inputDevices = getInputDevicesLocked();
            mPendingArgs.emplace_back(
                    NotifyInputDevicesChangedArgs{mContext.getNextId(), inputDevices});
        }

        std::swap(notifyArgs, mPendingArgs);

        for (const NotifyArgs& args : notifyArgs) {
            mLastUsedDeviceId = getDeviceIdOfNewGesture(args).value_or(mLastUsedDeviceId);
        }
    } // release lock

    // 通知到监听器，在创建InputReader时有将InputDispacher封装为监听器传给InputReader，所以这里可以把事件发给InputReader。
    for (const NotifyArgs& args : notifyArgs) {
        mNextListener.notify(args);
    }

    if (inputDevicesChanged) {
        mPolicy->notifyInputDevicesChanged(inputDevices);
    }

    for (const auto& args : notifyArgs) {
        const auto* motionArgs = std::get_if<NotifyMotionArgs>(&args);
        if (motionArgs != nullptr && isStylusPointerGestureStart(*motionArgs)) {
            mPolicy->notifyStylusGestureStarted(motionArgs->deviceId, motionArgs->eventTime);
        }
    }
}

3. getEvents负责从设备节点中读取RawEvent。

// frameworks/native/services/inputflinger/reader/EventHub.cpp

std::vector<RawEvent> EventHub::getEvents(int timeoutMillis) {
    std::scoped_lock _l(mLock);

    std::array<input_event, EVENT_BUFFER_SIZE> readBuffer;

    std::vector<RawEvent> events;
    bool awoken = false;
    for (;;) {
        nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);

        // 如果需要重新打开设备，先将设备关掉
        if (mNeedToReopenDevices) {
            mNeedToReopenDevices = false;

            ALOGI("Reopening all input devices due to a configuration change.");

            closeAllDevicesLocked();
            mNeedToScanDevices = true;
            break; // return to the caller before we actually rescan
        }

        // 报告被删除的设备
        for (auto it = mClosingDevices.begin(); it != mClosingDevices.end();) {
            std::unique_ptr<Device> device = std::move(*it);
            ALOGV("Reporting device closed: id=%d, name=%s\n", device->id, device->path.c_str());
            const int32_t deviceId = (device->id == mBuiltInKeyboardId)
                    ? ReservedInputDeviceId::BUILT_IN_KEYBOARD_ID
                    : device->id;
            events.push_back({
                    .when = now,
                    .deviceId = deviceId,
                    .type = DEVICE_REMOVED,
            });
            it = mClosingDevices.erase(it);
            mNeedToSendFinishedDeviceScan = true;
            if (events.size() == EVENT_BUFFER_SIZE) {
                break;
            }
        }
    
        // 如果需要就扫描设备
        if (mNeedToScanDevices) {
            mNeedToScanDevices = false;
            scanDevicesLocked();
            mNeedToSendFinishedDeviceScan = true;
        }
        
        // 报告有设备被添加
        while (!mOpeningDevices.empty()) {
            std::unique_ptr<Device> device = std::move(*mOpeningDevices.rbegin());
            mOpeningDevices.pop_back();
            ALOGV("Reporting device opened: id=%d, name=%s\n", device->id, device->path.c_str());
            const int32_t deviceId = device->id == mBuiltInKeyboardId ? 0 : device->id;
            events.push_back({
                    .when = now,
                    .deviceId = deviceId,
                    .type = DEVICE_ADDED,
            });

            // Try to find a matching video device by comparing device names
            for (auto it = mUnattachedVideoDevices.begin(); it != mUnattachedVideoDevices.end();
                 it++) {
                std::unique_ptr<TouchVideoDevice>& videoDevice = *it;
                if (tryAddVideoDeviceLocked(*device, videoDevice)) {
                    // videoDevice was transferred to 'device'
                    it = mUnattachedVideoDevices.erase(it);
                    break;
                }
            }

            auto [dev_it, inserted] = mDevices.insert_or_assign(device->id, std::move(device));
            if (!inserted) {
                ALOGW("Device id %d exists, replaced.", device->id);
            }
            mNeedToSendFinishedDeviceScan = true;
            if (events.size() == EVENT_BUFFER_SIZE) {
                break;
            }
        }
        
         
        // 报告设备扫描完成
        if (mNeedToSendFinishedDeviceScan) {
            mNeedToSendFinishedDeviceScan = false;
            events.push_back({
                    .when = now,
                    .type = FINISHED_DEVICE_SCAN,
            });
            if (events.size() == EVENT_BUFFER_SIZE) {
                break;
            }
        }

        // 获取输入事件
        bool deviceChanged = false;
        while (mPendingEventIndex < mPendingEventCount) {
            const struct epoll_event& eventItem = mPendingEventItems[mPendingEventIndex++];
            if (eventItem.data.fd == mINotifyFd) {
                if (eventItem.events & EPOLLIN) {
                    mPendingINotify = true;
                } else {
                    ALOGW("Received unexpected epoll event 0x%08x for INotify.", eventItem.events);
                }
                continue;
            }

            if (eventItem.data.fd == mWakeReadPipeFd) {
                if (eventItem.events & EPOLLIN) {
                    ALOGV("awoken after wake()");
                    awoken = true;
                    char wakeReadBuffer[16];
                    ssize_t nRead;
                    do {
                        nRead = read(mWakeReadPipeFd, wakeReadBuffer, sizeof(wakeReadBuffer));
                    } while ((nRead == -1 && errno == EINTR) || nRead == sizeof(wakeReadBuffer));
                } else {
                    ALOGW("Received unexpected epoll event 0x%08x for wake read pipe.",
                          eventItem.events);
                }
                continue;
            }

            Device* device = getDeviceByFdLocked(eventItem.data.fd);
            if (device == nullptr) {
                ALOGE("Received unexpected epoll event 0x%08x for unknown fd %d.", eventItem.events,
                      eventItem.data.fd);
                ALOG_ASSERT(!DEBUG);
                continue;
            }
            if (device->videoDevice && eventItem.data.fd == device->videoDevice->getFd()) {
                if (eventItem.events & EPOLLIN) {
                    size_t numFrames = device->videoDevice->readAndQueueFrames();
                    if (numFrames == 0) {
                        ALOGE("Received epoll event for video device %s, but could not read frame",
                              device->videoDevice->getName().c_str());
                    }
                } else if (eventItem.events & EPOLLHUP) {
                    // TODO(b/121395353) - consider adding EPOLLRDHUP
                    ALOGI("Removing video device %s due to epoll hang-up event.",
                          device->videoDevice->getName().c_str());
                    unregisterVideoDeviceFromEpollLocked(*device->videoDevice);
                    device->videoDevice = nullptr;
                } else {
                    ALOGW("Received unexpected epoll event 0x%08x for device %s.", eventItem.events,
                          device->videoDevice->getName().c_str());
                    ALOG_ASSERT(!DEBUG);
                }
                continue;
            }
            // This must be an input event
            if (eventItem.events & EPOLLIN) {
                int32_t readSize =
                        read(device->fd, readBuffer.data(),
                             sizeof(decltype(readBuffer)::value_type) * readBuffer.size());
                if (readSize == 0 || (readSize < 0 && errno == ENODEV)) {
                    // Device was removed before INotify noticed.
                    ALOGW("could not get event, removed? (fd: %d size: %" PRId32
                          " capacity: %zu errno: %d)\n",
                          device->fd, readSize, readBuffer.size(), errno);
                    deviceChanged = true;
                    closeDeviceLocked(*device);
                } else if (readSize < 0) {
                    if (errno != EAGAIN && errno != EINTR) {
                        ALOGW("could not get event (errno=%d)", errno);
                    }
                } else if ((readSize % sizeof(struct input_event)) != 0) {
                    ALOGE("could not get event (wrong size: %d)", readSize);
                } else {
                    const int32_t deviceId = device->id == mBuiltInKeyboardId ? 0 : device->id;

                    const size_t count = size_t(readSize) / sizeof(struct input_event);
                    for (size_t i = 0; i < count; i++) {
                        struct input_event& iev = readBuffer[i];
                        device->trackInputEvent(iev);
                        events.push_back({
                                .when = processEventTimestamp(iev),
                                .readTime = systemTime(SYSTEM_TIME_MONOTONIC),
                                .deviceId = deviceId,
                                .type = iev.type,
                                .code = iev.code,
                                .value = iev.value,
                        });
                    }
                    if (events.size() >= EVENT_BUFFER_SIZE) {
                        // The result buffer is full.  Reset the pending event index
                        // so we will try to read the device again on the next iteration.
                        mPendingEventIndex -= 1;
                        break;
                    }
                }
            } else if (eventItem.events & EPOLLHUP) {
                ALOGI("Removing device %s due to epoll hang-up event.",
                      device->identifier.name.c_str());
                deviceChanged = true;
                closeDeviceLocked(*device);
            } else {
                ALOGW("Received unexpected epoll event 0x%08x for device %s.", eventItem.events,
                      device->identifier.name.c_str());
            }
        }

        // readNotify() will modify the list of devices so this must be done after
        // processing all other events to ensure that we read all remaining events
        // before closing the devices.
        if (mPendingINotify && mPendingEventIndex >= mPendingEventCount) {
            mPendingINotify = false;
            const auto res = readNotifyLocked();
            if (!res.ok()) {
                ALOGW("Failed to read from inotify: %s", res.error().message().c_str());
            }
            deviceChanged = true;
        }

        // Report added or removed devices immediately.
        if (deviceChanged) {
            continue;
        }

        // Return now if we have collected any events or if we were explicitly awoken.
        if (!events.empty() || awoken) {
            break;
        }

        // Poll for events.
        // When a device driver has pending (unread) events, it acquires
        // a kernel wake lock.  Once the last pending event has been read, the device
        // driver will release the kernel wake lock, but the epoll will hold the wakelock,
        // since we are using EPOLLWAKEUP. The wakelock is released by the epoll when epoll_wait
        // is called again for the same fd that produced the event.
        // Thus the system can only sleep if there are no events pending or
        // currently being processed.
        //
        // The timeout is advisory only.  If the device is asleep, it will not wake just to
        // service the timeout.
        mPendingEventIndex = 0;

        mLock.unlock(); // release lock before poll

        int pollResult = epoll_wait(mEpollFd, mPendingEventItems, EPOLL_MAX_EVENTS, timeoutMillis);

        mLock.lock(); // reacquire lock after poll

        if (pollResult == 0) {
            // Timed out.
            mPendingEventCount = 0;
            break;
        }

        if (pollResult < 0) {
            // An error occurred.
            mPendingEventCount = 0;

            // Sleep after errors to avoid locking up the system.
            // Hopefully the error is transient.
            if (errno != EINTR) {
                ALOGW("poll failed (errno=%d)\n", errno);
                usleep(100000);
            }
        } else {
            // Some events occurred.
            mPendingEventCount = size_t(pollResult);
        }
    }

    // All done, return the number of events we read.
    return events;
}

4. 这里除了处理输入事件外，还会处理设备的添加、删除以及扫描。这里主要关注输入事件。

// frameworks/native/services/inputflinger/reader/InputReader.cpp

std::list<NotifyArgs> InputReader::processEventsLocked(const RawEvent* rawEvents, size_t count) {
    std::list<NotifyArgs> out;
    for (const RawEvent* rawEvent = rawEvents; count;) {
        int32_t type = rawEvent->type;
        size_t batchSize = 1;
        if (type < EventHubInterface::FIRST_SYNTHETIC_EVENT) {
            int32_t deviceId = rawEvent->deviceId;
            while (batchSize < count) {
                if (rawEvent[batchSize].type >= EventHubInterface::FIRST_SYNTHETIC_EVENT ||
                    rawEvent[batchSize].deviceId != deviceId) {
                    break;
                }
                batchSize += 1;
            }
            if (debugRawEvents()) {
                ALOGD("BatchSize: %zu Count: %zu", batchSize, count);
            }
            // 处理输入事件
            out += processEventsForDeviceLocked(deviceId, rawEvent, batchSize);
        } else {
            switch (rawEvent->type) {
                case EventHubInterface::DEVICE_ADDED:
                    addDeviceLocked(rawEvent->when, rawEvent->deviceId);
                    break;
                case EventHubInterface::DEVICE_REMOVED:
                    removeDeviceLocked(rawEvent->when, rawEvent->deviceId);
                    break;
                case EventHubInterface::FINISHED_DEVICE_SCAN:
                    handleConfigurationChangedLocked(rawEvent->when);
                    break;
                default:
                    ALOG_ASSERT(false); // can't happen
                    break;
            }
        }
        count -= batchSize;
        rawEvent += batchSize;
    }
    return out;
}

5. 找到事件所对应的InputDevice处理事件。

// frameworks/native/services/inputflinger/reader/InputReader.cpp

std::list<NotifyArgs> InputReader::processEventsForDeviceLocked(int32_t eventHubId,
                                                                const RawEvent* rawEvents,
                                                                size_t count) {
    auto deviceIt = mDevices.find(eventHubId);
    if (deviceIt == mDevices.end()) {
        ALOGW("Discarding event for unknown eventHubId %d.", eventHubId);
        return {};
    }

    std::shared_ptr<InputDevice>& device = deviceIt->second;
    if (device->isIgnored()) {
        // ALOGD("Discarding event for ignored deviceId %d.", deviceId);
        return {};
    }

    return device->process(rawEvents, count);
}

6. 把rawEvent交给设备相关的Mapper处理

frameworks/native/services/inputflinger/reader/InputDevice.cpp

std::list<NotifyArgs> InputDevice::process(const RawEvent* rawEvents, size_t count) {
    std::list<NotifyArgs> out;
    for (const RawEvent* rawEvent = rawEvents; count != 0; rawEvent++) {
        if (debugRawEvents()) {
            const auto [type, code, value] =
                    InputEventLookup::getLinuxEvdevLabel(rawEvent->type, rawEvent->code,
                                                         rawEvent->value);
            ALOGD("Input event: eventHubDevice=%d type=%s code=%s value=%s when=%" PRId64,
                  rawEvent->deviceId, type.c_str(), code.c_str(), value.c_str(), rawEvent->when);
        }

        if (mDropUntilNextSync) {
            if (rawEvent->type == EV_SYN && rawEvent->code == SYN_REPORT) {
                out += reset(rawEvent->when);
                mDropUntilNextSync = false;
                ALOGD_IF(debugRawEvents(), "Recovered from input event buffer overrun.");
            } else {
                ALOGD_IF(debugRawEvents(),
                         "Dropped input event while waiting for next input sync.");
            }
        } else if (rawEvent->type == EV_SYN && rawEvent->code == SYN_DROPPED) {
            ALOGI("Detected input event buffer overrun for device %s.", getName().c_str());
            mDropUntilNextSync = true;
        } else {
            for_each_mapper_in_subdevice(rawEvent->deviceId, [&](InputMapper& mapper) {
                out += mapper.process(*rawEvent);
            });
        }
        --count;
    }
    postProcess(out);
    return out;
}

7. 设备相关的Mapper是在创建InputDevice的时候根据设备类型添加的。我们这里只分析触摸事件，可以看到和触摸事件相关的有SingleTouchInputMapper（单指触摸）和MultiTouchInputMapper（多指触摸）。

std::vector<std::unique_ptr<InputMapper>> InputDevice::createMappers(
        InputDeviceContext& contextPtr, const InputReaderConfiguration& readerConfig) {
    ftl::Flags<InputDeviceClass> classes = contextPtr.getDeviceClasses();
    std::vector<std::unique_ptr<InputMapper>> mappers;

    // Switch-like devices.
    if (classes.test(InputDeviceClass::SWITCH)) {
        mappers.push_back(createInputMapper<SwitchInputMapper>(contextPtr, readerConfig));
    }

    // Scroll wheel-like devices.
    if (classes.test(InputDeviceClass::ROTARY_ENCODER)) {
        mappers.push_back(createInputMapper<RotaryEncoderInputMapper>(contextPtr, readerConfig));
    }

    // Vibrator-like devices.
    if (classes.test(InputDeviceClass::VIBRATOR)) {
        mappers.push_back(createInputMapper<VibratorInputMapper>(contextPtr, readerConfig));
    }

    // Battery-like devices or light-containing devices.
    // PeripheralController will be created with associated EventHub device.
    if (classes.test(InputDeviceClass::BATTERY) || classes.test(InputDeviceClass::LIGHT)) {
        mController = std::make_unique<PeripheralController>(contextPtr);
    }

    // Keyboard-like devices.
    uint32_t keyboardSource = 0;
    if (classes.test(InputDeviceClass::KEYBOARD)) {
        keyboardSource |= AINPUT_SOURCE_KEYBOARD;
    }
    if (classes.test(InputDeviceClass::DPAD)) {
        keyboardSource |= AINPUT_SOURCE_DPAD;
    }
    if (classes.test(InputDeviceClass::GAMEPAD)) {
        keyboardSource |= AINPUT_SOURCE_GAMEPAD;
    }

    if (keyboardSource != 0) {
        mappers.push_back(
                createInputMapper<KeyboardInputMapper>(contextPtr, readerConfig, keyboardSource));
    }

    // Cursor-like devices.
    if (classes.test(InputDeviceClass::CURSOR)) {
        mappers.push_back(createInputMapper<CursorInputMapper>(contextPtr, readerConfig));
    }

    // Touchscreens and touchpad devices.
    if (classes.test(InputDeviceClass::TOUCHPAD) && classes.test(InputDeviceClass::TOUCH_MT)) {
        mappers.push_back(createInputMapper<TouchpadInputMapper>(contextPtr, readerConfig));
    } else if (classes.test(InputDeviceClass::TOUCH_MT)) {
        mappers.push_back(createInputMapper<MultiTouchInputMapper>(contextPtr, readerConfig));
    } else if (classes.test(InputDeviceClass::TOUCH)) {
        mappers.push_back(createInputMapper<SingleTouchInputMapper>(contextPtr, readerConfig));
    }

    // Joystick-like devices.
    if (classes.test(InputDeviceClass::JOYSTICK)) {
        mappers.push_back(createInputMapper<JoystickInputMapper>(contextPtr, readerConfig));
    }

    // Motion sensor enabled devices.
    if (classes.test(InputDeviceClass::SENSOR)) {
        mappers.push_back(createInputMapper<SensorInputMapper>(contextPtr, readerConfig));
    }

    // External stylus-like devices.
    if (classes.test(InputDeviceClass::EXTERNAL_STYLUS)) {
        mappers.push_back(createInputMapper<ExternalStylusInputMapper>(contextPtr, readerConfig));
    }
    return mappers;
}

8. Mapper的主要作用是将设备上报的RawEvent累加到一起，为转换成InputEvent做准备。

// frameworks/native/services/inputflinger/reader/mapper/SingleTouchInputMapper.cpp

std::list<NotifyArgs> SingleTouchInputMapper::process(const RawEvent& rawEvent) {
    //TouchInputMapper是SingleTouchInputMapper的父类
    std::list<NotifyArgs> out = TouchInputMapper::process(rawEvent);

    mSingleTouchMotionAccumulator.process(rawEvent);
    return out;
}

9. 我们可以用getevent工具查看下触摸屏上报的事件流，下面每一行都是一个RawEvent，第一列为type，第二列为code，第三列为value。

10. SingleTouchMotionAccumulator会根据RawEvent的code，将value存入对应的变量

// frameworks/native/services/inputflinger/reader/mapper/accumulator/SingleTouchMotionAccumulator.cpp

void SingleTouchMotionAccumulator::process(const RawEvent& rawEvent) {
    if (rawEvent.type == EV_ABS) {
        switch (rawEvent.code) {
            case ABS_X:
                mAbsX = rawEvent.value;
                break;
            case ABS_Y:
                mAbsY = rawEvent.value;
                break;
            case ABS_PRESSURE:
                mAbsPressure = rawEvent.value;
                break;
            case ABS_TOOL_WIDTH:
                mAbsToolWidth = rawEvent.value;
                break;
            case ABS_DISTANCE:
                mAbsDistance = rawEvent.value;
                break;
            case ABS_TILT_X:
                mAbsTiltX = rawEvent.value;
                break;
            case ABS_TILT_Y:
                mAbsTiltY = rawEvent.value;
                break;
        }
    }
}

11. 只有遇到type为EV_SYN code为SYN_REPORT的RawEvent才会返回非空的NotifyArgs列表。

// frameworks/native/services/inputflinger/reader/mapper/TouchInputMapper.cpp

std::list<NotifyArgs> TouchInputMapper::process(const RawEvent& rawEvent) {
    mCursorButtonAccumulator.process(rawEvent);
    mCursorScrollAccumulator.process(rawEvent);
    mTouchButtonAccumulator.process(rawEvent);

    std::list<NotifyArgs> out;
    if (rawEvent.type == EV_SYN && rawEvent.code == SYN_REPORT) {
        out += sync(rawEvent.when, rawEvent.readTime);
    }
    return out;
}

std::list<NotifyArgs> TouchInputMapper::sync(nsecs_t when, nsecs_t readTime) {
    std::list<NotifyArgs> out;
    if (mDeviceMode == DeviceMode::DISABLED) {
        // Only save the last pending state when the device is disabled.
        mRawStatesPending.clear();
    }
    // Push a new state.
    mRawStatesPending.emplace_back();
    
    RawState& next = mRawStatesPending.back();
    next.clear();
    next.when = when;
    next.readTime = readTime;

    // Sync button state.
    next.buttonState = filterButtonState(mConfig,
                                         mTouchButtonAccumulator.getButtonState() |
                                                 mCursorButtonAccumulator.getButtonState());

    // Sync scroll
    next.rawVScroll = mCursorScrollAccumulator.getRelativeVWheel();
    next.rawHScroll = mCursorScrollAccumulator.getRelativeHWheel();
    mCursorScrollAccumulator.finishSync();

    // 同步触摸数据
    syncTouch(when, &next);

    // The last RawState is the actually second to last, since we just added a new state
    const RawState& last =
            mRawStatesPending.size() == 1 ? mCurrentRawState : mRawStatesPending.rbegin()[1];

    std::tie(next.when, next.readTime) =
            applyBluetoothTimestampSmoothening(getDeviceContext().getDeviceIdentifier(), when,
                                               readTime, last.when);

    // Assign pointer ids.
    if (!mHavePointerIds) {
        assignPointerIds(last, next);
    }
    
    // 处理触摸
    out += processRawTouches(/*timeout=*/false);
    return out;
}

12. 将SingleTouchMotionAccumulator数据同步到outState中

// frameworks/native/services/inputflinger/reader/mapper/SingleTouchInputMapper.cpp

void SingleTouchInputMapper::syncTouch(nsecs_t when, RawState* outState) {
    if (mTouchButtonAccumulator.isToolActive()) {
        outState->rawPointerData.pointerCount = 1;
        outState->rawPointerData.idToIndex[0] = 0;

        bool isHovering = mTouchButtonAccumulator.getToolType() != ToolType::MOUSE &&
                (mTouchButtonAccumulator.isHovering() ||
                 (mRawPointerAxes.pressure.valid &&
                  mSingleTouchMotionAccumulator.getAbsolutePressure() <= 0));
        outState->rawPointerData.markIdBit(0, isHovering);

        RawPointerData::Pointer& outPointer = outState->rawPointerData.pointers[0];
        outPointer.id = 0;
        outPointer.x = mSingleTouchMotionAccumulator.getAbsoluteX();
        outPointer.y = mSingleTouchMotionAccumulator.getAbsoluteY();
        outPointer.pressure = mSingleTouchMotionAccumulator.getAbsolutePressure();
        outPointer.touchMajor = 0;
        outPointer.touchMinor = 0;
        outPointer.toolMajor = mSingleTouchMotionAccumulator.getAbsoluteToolWidth();
        outPointer.toolMinor = mSingleTouchMotionAccumulator.getAbsoluteToolWidth();
        outPointer.orientation = 0;
        outPointer.distance = mSingleTouchMotionAccumulator.getAbsoluteDistance();
        outPointer.tiltX = mSingleTouchMotionAccumulator.getAbsoluteTiltX();
        outPointer.tiltY = mSingleTouchMotionAccumulator.getAbsoluteTiltY();
        outPointer.toolType = mTouchButtonAccumulator.getToolType();
        if (outPointer.toolType == ToolType::UNKNOWN) {
            outPointer.toolType = ToolType::FINGER;
        }
        outPointer.isHovering = isHovering;
    }
}

• 启动流程
• 设备添加流程
• 窗口信息更新
• InputChannel通信
• InputReader读取事件