Android7 InputReader InputDispatcher Key Touch

Android 输入事件的一般流程

EventHub

1. EventHub 事件枢纽，可以多路复用监听/dev/input/目录 文件的变化；
2. getEvents步骤：
   (1) . 开始循环执行，直至已经收集了任何事件，或者我们被显式地唤醒，现在返回。
   a. Reopen input devices if needed.
   b. Report any devices that had last been added/removed.
   c. scan devices if Needed, add devices / remove devices.
   d. product adding devices event if needed.
   e. product finishing scan devices event if needed.
   f. start grab the next input event really. //多路复用监听fd,
   g. readNotify()将修改设备列表，因此必须在处理所有其他事件之后完 成，以确保在关闭设备之前读取所有剩余事件。
   h. 若上一个动作g执行,Report added or removed devices immediately.
   i. 如果我们已经收集了任何事件，或者我们被显式地唤醒，现在返回。

多路复用监听事件补充：

		/*
		man help:
		EPOLLIN       连接到达；有数据来临；
		The associated file is available for read(2) operations.
		EPOLLOUT      有数据要写
		The associated file is available for write(2) operations.
		EPOLLRDHUP    表示读关闭。
		如果有EPOLLRDHUP，检测它就可以直到是对方关闭；否则就用上面方法。
		EPOLLHUP 表示读写都关闭。
		*/
					if (eventItem.events & EPOLLIN) {
					...
		            } else if (eventItem.events & EPOLLHUP) {
		                ALOGI("Removing device %s due to epoll hang-up event.",
		                        device->identifier.name.string());
		                deviceChanged = true;
		                closeDeviceLocked(device);
		            } else {
		                ALOGW("Received unexpected epoll event 0x%08x for device %s.",
		                        eventItem.events, device->identifier.name.string());
		            }

EventHub getEvents 函数：

size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSize) {
    ALOG_ASSERT(bufferSize >= 1);

    AutoMutex _l(mLock);

    struct input_event readBuffer[bufferSize];

    RawEvent* event = buffer;
    size_t capacity = bufferSize;
    bool awoken = false;
    for (;;) {
        nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);

        // Reopen input devices if needed.
        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
        }

        // Report any devices that had last been added/removed.
        while (mClosingDevices) {
            Device* device = mClosingDevices;
            ALOGV("Reporting device closed: id=%d, name=%s\n",
                 device->id, device->path.string());
            mClosingDevices = device->next;
            event->when = now;
            event->deviceId = device->id == mBuiltInKeyboardId ? BUILT_IN_KEYBOARD_ID : device->id;
            event->type = DEVICE_REMOVED;
            event += 1;
            delete device;
            mNeedToSendFinishedDeviceScan = true;
            if (--capacity == 0) {
                break;
            }
        }

        if (mNeedToScanDevices) {
            mNeedToScanDevices = false;
            scanDevicesLocked();
            mNeedToSendFinishedDeviceScan = true;
        }

        while (mOpeningDevices != NULL) {
            Device* device = mOpeningDevices;
            ALOGV("Reporting device opened: id=%d, name=%s\n",
                 device->id, device->path.string());
            mOpeningDevices = device->next;
            event->when = now;
            event->deviceId = device->id == mBuiltInKeyboardId ? 0 : device->id;
            event->type = DEVICE_ADDED;
            event += 1;
            mNeedToSendFinishedDeviceScan = true;
            if (--capacity == 0) {
                break;
            }
        }

        if (mNeedToSendFinishedDeviceScan) {
            mNeedToSendFinishedDeviceScan = false;
            event->when = now;
            event->type = FINISHED_DEVICE_SCAN;
            event += 1;
            if (--capacity == 0) {
                break;
            }
        }

        // Grab the next input event.
        bool deviceChanged = false;
        while (mPendingEventIndex < mPendingEventCount) {
            const struct epoll_event& eventItem = mPendingEventItems[mPendingEventIndex++];
            if (eventItem.data.u32 == EPOLL_ID_INOTIFY) {
                if (eventItem.events & EPOLLIN) {
                    mPendingINotify = true;
                } else {
                    ALOGW("Received unexpected epoll event 0x%08x for INotify.", eventItem.events);
                }
                continue;
            }

            if (eventItem.data.u32 == EPOLL_ID_WAKE) {
                if (eventItem.events & EPOLLIN) {
                    ALOGV("awoken after wake()");
                    awoken = true;
                    char buffer[16];
                    ssize_t nRead;
                    do {
                        nRead = read(mWakeReadPipeFd, buffer, sizeof(buffer));
                    } while ((nRead == -1 && errno == EINTR) || nRead == sizeof(buffer));
                } else {
                    ALOGW("Received unexpected epoll event 0x%08x for wake read pipe.",
                            eventItem.events);
                }
                continue;
            }

            ssize_t deviceIndex = mDevices.indexOfKey(eventItem.data.u32);
            if (deviceIndex < 0) {
                ALOGW("Received unexpected epoll event 0x%08x for unknown device id %d.",
                        eventItem.events, eventItem.data.u32);
                continue;
            }

            Device* device = mDevices.valueAt(deviceIndex);
            if (eventItem.events & EPOLLIN) {
                int32_t readSize = read(device->fd, readBuffer,
                        sizeof(struct input_event) * capacity);
                if (readSize == 0 || (readSize < 0 && errno == ENODEV)) {
                    // Device was removed before INotify noticed.
                    ALOGW("could not get event, removed? (fd: %d size: %" PRId32
                            " bufferSize: %zu capacity: %zu errno: %d)\n",
                            device->fd, readSize, bufferSize, capacity, 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 {
                    int32_t deviceId = device->id == mBuiltInKeyboardId ? 0 : device->id;

                    size_t count = size_t(readSize) / sizeof(struct input_event);
                    for (size_t i = 0; i < count; i++) {
                        struct input_event& iev = readBuffer[i];
                        ALOGV("%s got: time=%d.%06d, type=%d, code=%d, value=%d",
                                device->path.string(),
                                (int) iev.time.tv_sec, (int) iev.time.tv_usec,
                                iev.type, iev.code, iev.value);

                        // Some input devices may have a better concept of the time
                        // when an input event was actually generated than the kernel
                        // which simply timestamps all events on entry to evdev.
                        // This is a custom Android extension of the input protocol
                        // mainly intended for use with uinput based device drivers.
                        if (iev.type == EV_MSC) {
                            if (iev.code == MSC_ANDROID_TIME_SEC) {
                                device->timestampOverrideSec = iev.value;
                                continue;
                            } else if (iev.code == MSC_ANDROID_TIME_USEC) {
                                device->timestampOverrideUsec = iev.value;
                                continue;
                            }
                        }
                        if (device->timestampOverrideSec || device->timestampOverrideUsec) {
                            iev.time.tv_sec = device->timestampOverrideSec;
                            iev.time.tv_usec = device->timestampOverrideUsec;
                            if (iev.type == EV_SYN && iev.code == SYN_REPORT) {
                                device->timestampOverrideSec = 0;
                                device->timestampOverrideUsec = 0;
                            }
                            ALOGV("applied override time %d.%06d",
                                    int(iev.time.tv_sec), int(iev.time.tv_usec));
                        }

                        // Use the time specified in the event instead of the current time
                        // so that downstream code can get more accurate estimates of
                        // event dispatch latency from the time the event is enqueued onto
                        // the evdev client buffer.
                        //
                        // The event's timestamp fortuitously uses the same monotonic clock
                        // time base as the rest of Android.  The kernel event device driver
                        // (drivers/input/evdev.c) obtains timestamps using ktime_get_ts().
                        // The systemTime(SYSTEM_TIME_MONOTONIC) function we use everywhere
                        // calls clock_gettime(CLOCK_MONOTONIC) which is implemented as a
                        // system call that also queries ktime_get_ts().
                        event->when = nsecs_t(iev.time.tv_sec) * 1000000000LL
                                + nsecs_t(iev.time.tv_usec) * 1000LL;
                        ALOGV("event time %" PRId64 ", now %" PRId64, event->when, now);

                        // Bug 7291243: Add a guard in case the kernel generates timestamps
                        // that appear to be far into the future because they were generated
                        // using the wrong clock source.
                        //
                        // This can happen because when the input device is initially opened
                        // it has a default clock source of CLOCK_REALTIME.  Any input events
                        // enqueued right after the device is opened will have timestamps
                        // generated using CLOCK_REALTIME.  We later set the clock source
                        // to CLOCK_MONOTONIC but it is already too late.
                        //
                        // Invalid input event timestamps can result in ANRs, crashes and
                        // and other issues that are hard to track down.  We must not let them
                        // propagate through the system.
                        //
                        // Log a warning so that we notice the problem and recover gracefully.
                        if (event->when >= now + 10 * 1000000000LL) {
                            // Double-check.  Time may have moved on.
                            nsecs_t time = systemTime(SYSTEM_TIME_MONOTONIC);
                            if (event->when > time) {
                                ALOGW("An input event from %s has a timestamp that appears to "
                                        "have been generated using the wrong clock source "
                                        "(expected CLOCK_MONOTONIC): "
                                        "event time %" PRId64 ", current time %" PRId64
                                        ", call time %" PRId64 ".  "
                                        "Using current time instead.",
                                        device->path.string(), event->when, time, now);
                                event->when = time;
                            } else {
                                ALOGV("Event time is ok but failed the fast path and required "
                                        "an extra call to systemTime: "
                                        "event time %" PRId64 ", current time %" PRId64
                                        ", call time %" PRId64 ".",
                                        event->when, time, now);
                            }
                        }
                        event->deviceId = deviceId;
                        event->type = iev.type;
                        event->code = iev.code;
                        event->value = iev.value;
                        event += 1;
                        capacity -= 1;
                    }
                    if (capacity == 0) {
                        // 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.string());
                deviceChanged = true;
                closeDeviceLocked(device);
            } else {
                ALOGW("Received unexpected epoll event 0x%08x for device %s.",
                        eventItem.events, device->identifier.name.string());
            }
        }

        // 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;
            readNotifyLocked();
            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 (event != buffer || awoken) {
            break;
        }

        // Poll for events.  Mind the wake lock dance!
        // We hold a wake lock at all times except during epoll_wait().  This works due to some
        // subtle choreography.  When a device driver has pending (unread) events, it acquires
        // a kernel wake lock.  However, once the last pending event has been read, the device
        // driver will release the kernel wake lock.  To prevent the system from going to sleep
        // when this happens, the EventHub holds onto its own user wake lock while the client
        // is processing events.  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, must be before release_wake_lock
        release_wake_lock(WAKE_LOCK_ID);

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

        acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);
        mLock.lock(); // reacquire lock after poll, must be after acquire_wake_lock

        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 event - buffer;
}

InputRead

1. InputManager 启动的一个线程主要用于循环去通过EventHub监听事件

InputDispatcher

1. inputManager 启动的一个线程主要用于循环的派发事件；

InputManager

1. 主要用来管理InputReader 和 InputDispatcher;

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "InputManager"

//#define LOG_NDEBUG 0

#include "InputManager.h"

#include <cutils/log.h>

namespace android {

InputManager::InputManager(
        const sp<EventHubInterface>& eventHub,
        const sp<InputReaderPolicyInterface>& readerPolicy,
        const sp<InputDispatcherPolicyInterface>& dispatcherPolicy) {
    mDispatcher = new InputDispatcher(dispatcherPolicy);
    mReader = new InputReader(eventHub, readerPolicy, mDispatcher);
    initialize();
}

InputManager::InputManager(
        const sp<InputReaderInterface>& reader,
        const sp<InputDispatcherInterface>& dispatcher) :
        mReader(reader),
        mDispatcher(dispatcher) {
    initialize();
}

InputManager::~InputManager() {
    stop();
}

void InputManager::initialize() {
    mReaderThread = new InputReaderThread(mReader);
    mDispatcherThread = new InputDispatcherThread(mDispatcher);
}

status_t InputManager::start() {
    status_t result = mDispatcherThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY);
    if (result) {
        ALOGE("Could not start InputDispatcher thread due to error %d.", result);
        return result;
    }

    result = mReaderThread->run("InputReader", PRIORITY_URGENT_DISPLAY);
    if (result) {
        ALOGE("Could not start InputReader thread due to error %d.", result);

        mDispatcherThread->requestExit();
        return result;
    }

    return OK;
}

status_t InputManager::stop() {
    status_t result = mReaderThread->requestExitAndWait();
    if (result) {
        ALOGW("Could not stop InputReader thread due to error %d.", result);
    }

    result = mDispatcherThread->requestExitAndWait();
    if (result) {
        ALOGW("Could not stop InputDispatcher thread due to error %d.", result);
    }

    return OK;
}

sp<InputReaderInterface> InputManager::getReader() {
    return mReader;
}

sp<InputDispatcherInterface> InputManager::getDispatcher() {
    return mDispatcher;
}

} // namespace android

Key

常见debug 工具 或 命令

1. input 自动化测试常用(命令每次重新执行通过app_process是用来调用java代码的，耗时1到2s ，可以做优化)
2. dumpsys input 调试常用，可以查看当前按键和触屏情况；
3. 打开开发者选项的命令：
   settings put secure user_setup_complete 1
   settings put global device_provisioned 1
   am start -n com.android.launcher/com.android.launcher2.Launcher
4. 控制log的相关命令：
   关闭所有log: setprop persist.log.tag S
   打开指定TAG的log： setprop persist.log.tag.TAG V
5. kill -3 PID命令获取java应用堆栈信息,一般可以用来调查APP无法接受按键和触屏事件的内部原因

Android 框架Key原理

dumpsys input:

Event Hub State:
  BuiltInKeyboardId: 5
  Devices:
    -1: Virtual
      Classes: 0x40000023
      Path: <virtual>
      Enabled: true
      Descriptor: a718a782d34bc767f4689c232d64d527998ea7fd
      Location:
      ControllerNumber: 0
      UniqueId: <virtual>
      Identifier: bus=0x0000, vendor=0x0000, product=0x0000, version=0x0000
      KeyLayoutFile: /system/usr/keylayout/Generic.kl
      KeyCharacterMapFile: /system/usr/keychars/Virtual.kcm
      ConfigurationFile:
      HaveKeyboardLayoutOverlay: false
Input Reader State:
  Device -1: Virtual
    Generation: 2
    IsExternal: false
    HasMic:     false
    Sources: 0x00000301
    KeyboardType: 2
    Keyboard Input Mapper:
      Parameters:
        HasAssociatedDisplay: false
        OrientationAware: false
        HandlesKeyRepeat: false
      KeyboardType: 2
      Orientation: 0
      KeyDowns: 0 keys currently down
      MetaState: 0x0
      DownTime: 0

根据个人的项目经验， KeyLayoutFile条目中看到加载的按键映射文件，都是根据厂商ID和产品ID匹配对应文件的，例如vendor为0x3697，product 为0x0001，那么对应的配置文件为/system/usr/keylayout/Vendor_3697_Product_0001.kl.

常见需求

Touch

常见debug 工具

Android 框架Touch原理

常见需求