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需求场景

纯KeyCode 快捷操作

• 经常在代码中实现返回、Home 、音量加减、截屏 等功能实现，代码中硬编码 shell 脚本 模拟 KeyCode事件
• 物理按键调试，模拟物理按键测试用：按键功能，物理按键驱动层已经调试完成，但有没有完整的硬件方便调试，应用层模拟物理按键功能来调试。比如：Android方案中，电视产品、音箱产品、带屏的Android各种方案
  都是有物理按键的，如果自己测试验证物理按键的功能呢，那就需要自己来模拟KeyEventCode 来模拟按键，先自测。
• 遥控器功能【投影产品】：一般根据蓝牙方案、红外方案实现遥控功能，传递给系统的都是Key的键值，系统自带标准的键值，这样就形成一套标准的流程了，系统根据键值做出反馈或者系统收到对应的键值反馈给上层，上层来处理业务逻辑。
• 游戏类产品，手柄的控制。手柄上面的功能按钮其实就是一些物理按键，点击物理按键，系统或者应用监听后给出反馈。那么在实际测试的时候，就需要模拟按键来测试验证
• 如果Android平板作为电脑使用，插上USB，那么Android平板作为电脑来时候，就必须响应键盘上面的所有按键，这些物理按键也是通过KeyCode
  来传递给系统，准确来说是系统来响应这些KeyCode,进而再处理响应的逻辑。

总的来讲：系统响应KeyCode，这些KeyCode是外设作为输入源，KeyCode 键值就是Android一套标准的协议

KeyCode 按键响应操作、拦截

比如物理按键操作之后，系统是如何分发、响应、处理、拦截呢？ 比如我们需要客制化一些物理按键功能，如何实现呢？

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一、工作中常用KeyCode

枚举值	键值	功能说明
KEYCODE_HOME	3	主屏幕键
KEYCODE_BACK	4	返回键
KEYCODE_DPAD_UP	19	向上方向键
KEYCODE_DPAD_DOWN	20	向下方向键
KEYCODE_DPAD_LEFT	21	向左方向键
KEYCODE_DPAD_RIGHT	22	向右方向键
KEYCODE_DPAD_CENTER	23	中心键
KEYCODE_VOLUME_UP	24	手机音量+
KEYCODE_VOLUME_DOWN	25	手机音量-
KEYCODE_POWER	26	电源键
KEYCODE_EXPLORER	64	启动浏览器程序
KEYCODE_MEDIA_PLAY_PAUSE	85	多媒体播放、暂停键
KEYCODE_MEDIA_STOP	86	停止键
KEYCODE_MEDIA_NEXT	87	下一首键
KEYCODE_MEDIA_PREVIOUS	88	上一首键
KEYCODE_MEDIA_REWIND	89	快退键
KEYCODE_MEDIA_FAST_FORWARD	90	快进键
KEYCODE_MEDIA_PLAY	126	播放键
KEYCODE_MEDIA_PAUSE	127	暂停键
KEYCODE_VOLUME_MUTE	164	手机扬声器静音
KEYCODE_APP_SWITCH	187	任务管理 最近历史任务
KEYCODE_MUSIC	209	启动音乐
KEYCODE_BRIGHTNESS_DOWN	220	亮度减少
KEYCODE_BRIGHTNESS_UP	221	亮度增加
KEYCODE_DPAD_DOWN_LEFT	269	向左下方向键
KEYCODE_DPAD_DOWN_RIGHT	271	向右下方向键
KEYCODE_DPAD_UP_LEFT	268	向左上方向键
KEYCODE_DPAD_UP_RIGHT	270	向右上方向键

备注：如何用命令来模拟执行按键操作
枚举方式：adb shell input keyevent KEYCODE_HOME

code方式：adb shell input keyevent 3

二、KeyCode大全

这里给出谷歌官方KeyEvent 事件，里面总结了所有的KeyCode
官方KeyCode

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三、KeyCode 响应事件

事件输入流程

从大的方向将，物理按键始于外部输入，在Kernel 响应，再传递到Service或者View层消费，对于Kernel层、系统层暂不研究。
输入设备键值从底层到应用层的映射流程

事件响应

源码分析

源码位置：
PhoneWindowManager
这里涉及到 源码中的PhoneWindowManager 来响应物理按键事件并进行分发：

// You can only start consuming the key gesture if ACTION_DOWN and repeat count// is 0. If you start intercepting the key halfway, then key will not be consumed// and will be sent to apps for processing too.// e.g. If a certain combination is only handled on ACTION_UP (i.e.// interceptShortcut() returns true only for ACTION_UP), then since we already// sent the ACTION_DOWN events to the application, we MUST also send the// ACTION_UP to the application.// So, to ensure that your intercept logic works properly, and we don't send any// conflicting events to application, make sure to consume the event on// ACTION_DOWN even if you want to do something on ACTION_UP. This is essential// to maintain event parity and to not have incomplete key gestures.@SuppressLint("MissingPermission")private boolean interceptSystemKeysAndShortcuts(IBinder focusedToken, KeyEvent event) {final boolean keyguardOn = keyguardOn();final int keyCode = event.getKeyCode();final int repeatCount = event.getRepeatCount();final int metaState = event.getMetaState();final boolean down = event.getAction() == KeyEvent.ACTION_DOWN;final boolean canceled = event.isCanceled();final int displayId = event.getDisplayId();final int deviceId = event.getDeviceId();final boolean firstDown = down && repeatCount == 0;// Cancel any pending meta actions if we see any other keys being pressed between the// down of the meta key and its corresponding up.if (mPendingMetaAction && !KeyEvent.isMetaKey(keyCode)) {mPendingMetaAction = false;}// Any key that is not Alt or Meta cancels Caps Lock combo tracking.if (mPendingCapsLockToggle && !KeyEvent.isMetaKey(keyCode) && !KeyEvent.isAltKey(keyCode)) {mPendingCapsLockToggle = false;}if (isUserSetupComplete() && !keyguardOn) {if (mModifierShortcutManager.interceptKey(event)) {dismissKeyboardShortcutsMenu();mPendingMetaAction = false;mPendingCapsLockToggle = false;return true;}}switch (keyCode) {case KeyEvent.KEYCODE_HOME:return handleHomeShortcuts(focusedToken, event);case KeyEvent.KEYCODE_MENU:// Hijack modified menu keys for debugging featuresfinal int chordBug = KeyEvent.META_SHIFT_ON;if (mEnableShiftMenuBugReports && firstDown&& (metaState & chordBug) == chordBug) {Intent intent = new Intent(Intent.ACTION_BUG_REPORT);mContext.sendOrderedBroadcastAsUser(intent, UserHandle.CURRENT,null, null, null, 0, null, null);logKeyboardSystemsEvent(event, KeyboardLogEvent.TRIGGER_BUG_REPORT);return true;}break;case KeyEvent.KEYCODE_RECENT_APPS:if (firstDown) {showRecentApps(false /* triggeredFromAltTab */);logKeyboardSystemsEvent(event, KeyboardLogEvent.RECENT_APPS);}return true;case KeyEvent.KEYCODE_APP_SWITCH:if (!keyguardOn) {if (firstDown) {preloadRecentApps();} else if (!down) {toggleRecentApps();logKeyboardSystemsEvent(event, KeyboardLogEvent.APP_SWITCH);}}return true;case KeyEvent.KEYCODE_A:if (firstDown && event.isMetaPressed()) {launchAssistAction(Intent.EXTRA_ASSIST_INPUT_HINT_KEYBOARD,deviceId, event.getEventTime(),AssistUtils.INVOCATION_TYPE_UNKNOWN);logKeyboardSystemsEvent(event, KeyboardLogEvent.LAUNCH_ASSISTANT);return true;}break;case KeyEvent.KEYCODE_H:case KeyEvent.KEYCODE_ENTER:if (event.isMetaPressed()) {return handleHomeShortcuts(focusedToken, event);}break;case KeyEvent.KEYCODE_I:if (firstDown && event.isMetaPressed()) {showSystemSettings();logKeyboardSystemsEvent(event, KeyboardLogEvent.LAUNCH_SYSTEM_SETTINGS);return true;}break;case KeyEvent.KEYCODE_L:if (firstDown && event.isMetaPressed()) {lockNow(null /* options */);logKeyboardSystemsEvent(event, KeyboardLogEvent.LOCK_SCREEN);return true;}break;case KeyEvent.KEYCODE_N:if (firstDown && event.isMetaPressed()) {if (event.isCtrlPressed()) {sendSystemKeyToStatusBarAsync(event);logKeyboardSystemsEvent(event, KeyboardLogEvent.OPEN_NOTES);} else {toggleNotificationPanel();logKeyboardSystemsEvent(event, KeyboardLogEvent.TOGGLE_NOTIFICATION_PANEL);}return true;}break;case KeyEvent.KEYCODE_S:if (firstDown && event.isMetaPressed() && event.isCtrlPressed()) {interceptScreenshotChord(SCREENSHOT_KEY_OTHER, 0 /*pressDelay*/);logKeyboardSystemsEvent(event, KeyboardLogEvent.TAKE_SCREENSHOT);return true;}break;case KeyEvent.KEYCODE_DEL:case KeyEvent.KEYCODE_ESCAPE:if (firstDown && event.isMetaPressed()) {logKeyboardSystemsEvent(event, KeyboardLogEvent.BACK);injectBackGesture(event.getDownTime());return true;}case KeyEvent.KEYCODE_DPAD_UP:if (firstDown && event.isMetaPressed() && event.isCtrlPressed()) {StatusBarManagerInternal statusbar = getStatusBarManagerInternal();if (statusbar != null) {statusbar.moveFocusedTaskToFullscreen(getTargetDisplayIdForKeyEvent(event));logKeyboardSystemsEvent(event, KeyboardLogEvent.MULTI_WINDOW_NAVIGATION);return true;}}break;case KeyEvent.KEYCODE_DPAD_DOWN:if (firstDown && event.isMetaPressed() && event.isCtrlPressed()) {StatusBarManagerInternal statusbar = getStatusBarManagerInternal();if (statusbar != null) {statusbar.enterDesktop(getTargetDisplayIdForKeyEvent(event));logKeyboardSystemsEvent(event, KeyboardLogEvent.DESKTOP_MODE);return true;}}break;case KeyEvent.KEYCODE_DPAD_LEFT:if (firstDown && event.isMetaPressed()) {if (event.isCtrlPressed()) {enterStageSplitFromRunningApp(true /* leftOrTop */);logKeyboardSystemsEvent(event, KeyboardLogEvent.SPLIT_SCREEN_NAVIGATION);} else {logKeyboardSystemsEvent(event, KeyboardLogEvent.BACK);injectBackGesture(event.getDownTime());}return true;}break;case KeyEvent.KEYCODE_DPAD_RIGHT:if (firstDown && event.isMetaPressed() && event.isCtrlPressed()) {enterStageSplitFromRunningApp(false /* leftOrTop */);logKeyboardSystemsEvent(event, KeyboardLogEvent.SPLIT_SCREEN_NAVIGATION);return true;}break;case KeyEvent.KEYCODE_SLASH:if (firstDown && event.isMetaPressed() && !keyguardOn) {toggleKeyboardShortcutsMenu(event.getDeviceId());logKeyboardSystemsEvent(event, KeyboardLogEvent.OPEN_SHORTCUT_HELPER);return true;}break;case KeyEvent.KEYCODE_ASSIST:Slog.wtf(TAG, "KEYCODE_ASSIST should be handled in interceptKeyBeforeQueueing");return true;case KeyEvent.KEYCODE_VOICE_ASSIST:Slog.wtf(TAG, "KEYCODE_VOICE_ASSIST should be handled in"+ " interceptKeyBeforeQueueing");return true;case KeyEvent.KEYCODE_VIDEO_APP_1:case KeyEvent.KEYCODE_VIDEO_APP_2:case KeyEvent.KEYCODE_VIDEO_APP_3:case KeyEvent.KEYCODE_VIDEO_APP_4:case KeyEvent.KEYCODE_VIDEO_APP_5:case KeyEvent.KEYCODE_VIDEO_APP_6:case KeyEvent.KEYCODE_VIDEO_APP_7:case KeyEvent.KEYCODE_VIDEO_APP_8:case KeyEvent.KEYCODE_FEATURED_APP_1:case KeyEvent.KEYCODE_FEATURED_APP_2:case KeyEvent.KEYCODE_FEATURED_APP_3:case KeyEvent.KEYCODE_FEATURED_APP_4:case KeyEvent.KEYCODE_DEMO_APP_1:case KeyEvent.KEYCODE_DEMO_APP_2:case KeyEvent.KEYCODE_DEMO_APP_3:case KeyEvent.KEYCODE_DEMO_APP_4:Slog.wtf(TAG, "KEYCODE_APP_X should be handled in interceptKeyBeforeQueueing");return true;case KeyEvent.KEYCODE_BRIGHTNESS_UP:case KeyEvent.KEYCODE_BRIGHTNESS_DOWN:if (down) {int direction = keyCode == KeyEvent.KEYCODE_BRIGHTNESS_UP ? 1 : -1;// Disable autobrightness if it's onint auto = Settings.System.getIntForUser(mContext.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS_MODE,Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL,UserHandle.USER_CURRENT_OR_SELF);if (auto != 0) {Settings.System.putIntForUser(mContext.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS_MODE,Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL,UserHandle.USER_CURRENT_OR_SELF);}int screenDisplayId = displayId < 0 ? DEFAULT_DISPLAY : displayId;float minLinearBrightness = mPowerManager.getBrightnessConstraint(PowerManager.BRIGHTNESS_CONSTRAINT_TYPE_MINIMUM);float maxLinearBrightness = mPowerManager.getBrightnessConstraint(PowerManager.BRIGHTNESS_CONSTRAINT_TYPE_MAXIMUM);float linearBrightness = mDisplayManager.getBrightness(screenDisplayId);float gammaBrightness = BrightnessUtils.convertLinearToGamma(linearBrightness);float adjustedGammaBrightness =gammaBrightness + 1f / BRIGHTNESS_STEPS * direction;adjustedGammaBrightness = MathUtils.constrain(adjustedGammaBrightness, 0f,1f);float adjustedLinearBrightness = BrightnessUtils.convertGammaToLinear(adjustedGammaBrightness);adjustedLinearBrightness = MathUtils.constrain(adjustedLinearBrightness,minLinearBrightness, maxLinearBrightness);mDisplayManager.setBrightness(screenDisplayId, adjustedLinearBrightness);Intent intent = new Intent(Intent.ACTION_SHOW_BRIGHTNESS_DIALOG);intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION| Intent.FLAG_ACTIVITY_NO_USER_ACTION);intent.putExtra(EXTRA_FROM_BRIGHTNESS_KEY, true);startActivityAsUser(intent, UserHandle.CURRENT_OR_SELF);logKeyboardSystemsEvent(event, KeyboardLogEvent.getBrightnessEvent(keyCode));}return true;case KeyEvent.KEYCODE_KEYBOARD_BACKLIGHT_DOWN:if (down) {mInputManagerInternal.decrementKeyboardBacklight(event.getDeviceId());logKeyboardSystemsEvent(event, KeyboardLogEvent.KEYBOARD_BACKLIGHT_DOWN);}return true;case KeyEvent.KEYCODE_KEYBOARD_BACKLIGHT_UP:if (down) {mInputManagerInternal.incrementKeyboardBacklight(event.getDeviceId());logKeyboardSystemsEvent(event, KeyboardLogEvent.KEYBOARD_BACKLIGHT_UP);}return true;case KeyEvent.KEYCODE_KEYBOARD_BACKLIGHT_TOGGLE:// TODO: Add logicif (!down) {logKeyboardSystemsEvent(event, KeyboardLogEvent.KEYBOARD_BACKLIGHT_TOGGLE);}return true;case KeyEvent.KEYCODE_VOLUME_UP:case KeyEvent.KEYCODE_VOLUME_DOWN:case KeyEvent.KEYCODE_VOLUME_MUTE:if (mUseTvRouting || mHandleVolumeKeysInWM) {// On TVs or when the configuration is enabled, volume keys never// go to the foreground app.dispatchDirectAudioEvent(event);return true;}// If the device is in VR mode and keys are "internal" (e.g. on the side of the// device), then drop the volume keys and don't forward it to the// application/dispatch the audio event.if (mDefaultDisplayPolicy.isPersistentVrModeEnabled()) {final InputDevice d = event.getDevice();if (d != null && !d.isExternal()) {return true;}}break;case KeyEvent.KEYCODE_TAB:if (firstDown && !keyguardOn && isUserSetupComplete()) {if (event.isMetaPressed()) {showRecentApps(false);logKeyboardSystemsEvent(event, KeyboardLogEvent.RECENT_APPS);return true;} else if (mRecentAppsHeldModifiers == 0) {final int shiftlessModifiers =event.getModifiers() & ~KeyEvent.META_SHIFT_MASK;if (KeyEvent.metaStateHasModifiers(shiftlessModifiers, KeyEvent.META_ALT_ON)) {mRecentAppsHeldModifiers = shiftlessModifiers;showRecentApps(true);logKeyboardSystemsEvent(event, KeyboardLogEvent.RECENT_APPS);return true;}}}break;case KeyEvent.KEYCODE_ALL_APPS:if (!down) {mHandler.removeMessages(MSG_HANDLE_ALL_APPS);Message msg = mHandler.obtainMessage(MSG_HANDLE_ALL_APPS);msg.setAsynchronous(true);msg.sendToTarget();logKeyboardSystemsEvent(event, KeyboardLogEvent.ALL_APPS);}return true;case KeyEvent.KEYCODE_NOTIFICATION:if (!down) {toggleNotificationPanel();logKeyboardSystemsEvent(event, KeyboardLogEvent.TOGGLE_NOTIFICATION_PANEL);}return true;case KeyEvent.KEYCODE_SEARCH:if (firstDown && !keyguardOn) {switch (mSearchKeyBehavior) {case SEARCH_BEHAVIOR_TARGET_ACTIVITY: {launchTargetSearchActivity();logKeyboardSystemsEvent(event, KeyboardLogEvent.LAUNCH_SEARCH);return true;}case SEARCH_BEHAVIOR_DEFAULT_SEARCH:default:break;}}break;case KeyEvent.KEYCODE_LANGUAGE_SWITCH:if (firstDown) {int direction = (metaState & KeyEvent.META_SHIFT_MASK) != 0 ? -1 : 1;sendSwitchKeyboardLayout(event, focusedToken, direction);logKeyboardSystemsEvent(event, KeyboardLogEvent.LANGUAGE_SWITCH);return true;}break;case KeyEvent.KEYCODE_META_LEFT:case KeyEvent.KEYCODE_META_RIGHT:if (down) {if (event.isAltPressed()) {mPendingCapsLockToggle = true;mPendingMetaAction = false;} else {mPendingCapsLockToggle = false;mPendingMetaAction = true;}} else {// Toggle Caps Lock on META-ALT.if (mPendingCapsLockToggle) {mInputManagerInternal.toggleCapsLock(event.getDeviceId());mPendingCapsLockToggle = false;logKeyboardSystemsEvent(event, KeyboardLogEvent.TOGGLE_CAPS_LOCK);} else if (mPendingMetaAction) {if (!canceled) {launchAllAppsViaA11y();logKeyboardSystemsEvent(event, KeyboardLogEvent.ACCESSIBILITY_ALL_APPS);}mPendingMetaAction = false;}}return true;case KeyEvent.KEYCODE_ALT_LEFT:case KeyEvent.KEYCODE_ALT_RIGHT:if (down) {if (event.isMetaPressed()) {mPendingCapsLockToggle = true;mPendingMetaAction = false;} else {mPendingCapsLockToggle = false;}} else {// hide recent if triggered by ALT-TAB.if (mRecentAppsHeldModifiers != 0&& (metaState & mRecentAppsHeldModifiers) == 0) {mRecentAppsHeldModifiers = 0;hideRecentApps(true, false);return true;}// Toggle Caps Lock on META-ALT.if (mPendingCapsLockToggle) {mInputManagerInternal.toggleCapsLock(event.getDeviceId());mPendingCapsLockToggle = false;logKeyboardSystemsEvent(event, KeyboardLogEvent.TOGGLE_CAPS_LOCK);return true;}}break;case KeyEvent.KEYCODE_CAPS_LOCK:if (!down) {logKeyboardSystemsEvent(event, KeyboardLogEvent.TOGGLE_CAPS_LOCK);}break;case KeyEvent.KEYCODE_STYLUS_BUTTON_PRIMARY:case KeyEvent.KEYCODE_STYLUS_BUTTON_SECONDARY:case KeyEvent.KEYCODE_STYLUS_BUTTON_TERTIARY:case KeyEvent.KEYCODE_STYLUS_BUTTON_TAIL:Slog.wtf(TAG, "KEYCODE_STYLUS_BUTTON_* should be handled in"+ " interceptKeyBeforeQueueing");return true;case KeyEvent.KEYCODE_SETTINGS:if (mShortPressOnSettingsBehavior == SHORT_PRESS_SETTINGS_NOTIFICATION_PANEL) {if (!down) {toggleNotificationPanel();logKeyboardSystemsEvent(event, KeyboardLogEvent.TOGGLE_NOTIFICATION_PANEL);}return true;}break;case KeyEvent.KEYCODE_STEM_PRIMARY:if (prepareToSendSystemKeyToApplication(focusedToken, event)) {// Send to app.return false;} else {// Intercepted.sendSystemKeyToStatusBarAsync(event);return true;}case KeyEvent.KEYCODE_SCREENSHOT:if (emojiAndScreenshotKeycodesAvailable() && down && repeatCount == 0) {interceptScreenshotChord(SCREENSHOT_KEY_OTHER, 0 /*pressDelay*/);}return true;}if (isValidGlobalKey(keyCode)&& mGlobalKeyManager.handleGlobalKey(mContext, keyCode, event)) {return true;}// Reserve all the META modifier combos for system behaviorreturn (metaState & KeyEvent.META_META_ON) != 0;}

源码举例说明

控制中，如下：

   case KeyEvent.KEYCODE_BRIGHTNESS_UP:case KeyEvent.KEYCODE_BRIGHTNESS_DOWN:if (down) {int direction = keyCode == KeyEvent.KEYCODE_BRIGHTNESS_UP ? 1 : -1;// Disable autobrightness if it's onint auto = Settings.System.getIntForUser(mContext.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS_MODE,Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL,UserHandle.USER_CURRENT_OR_SELF);if (auto != 0) {Settings.System.putIntForUser(mContext.getContentResolver(),Settings.System.SCREEN_BRIGHTNESS_MODE,Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL,UserHandle.USER_CURRENT_OR_SELF);}int screenDisplayId = displayId < 0 ? DEFAULT_DISPLAY : displayId;float minLinearBrightness = mPowerManager.getBrightnessConstraint(PowerManager.BRIGHTNESS_CONSTRAINT_TYPE_MINIMUM);float maxLinearBrightness = mPowerManager.getBrightnessConstraint(PowerManager.BRIGHTNESS_CONSTRAINT_TYPE_MAXIMUM);float linearBrightness = mDisplayManager.getBrightness(screenDisplayId);float gammaBrightness = BrightnessUtils.convertLinearToGamma(linearBrightness);float adjustedGammaBrightness =gammaBrightness + 1f / BRIGHTNESS_STEPS * direction;adjustedGammaBrightness = MathUtils.constrain(adjustedGammaBrightness, 0f,1f);float adjustedLinearBrightness = BrightnessUtils.convertGammaToLinear(adjustedGammaBrightness);adjustedLinearBrightness = MathUtils.constrain(adjustedLinearBrightness,minLinearBrightness, maxLinearBrightness);mDisplayManager.setBrightness(screenDisplayId, adjustedLinearBrightness);Intent intent = new Intent(Intent.ACTION_SHOW_BRIGHTNESS_DIALOG);intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION| Intent.FLAG_ACTIVITY_NO_USER_ACTION);intent.putExtra(EXTRA_FROM_BRIGHTNESS_KEY, true);startActivityAsUser(intent, UserHandle.CURRENT_OR_SELF);logKeyboardSystemsEvent(event, KeyboardLogEvent.getBrightnessEvent(keyCode));}return true;

这里消费亮度

业务逻辑如下：

• 获取当前亮度模式
• 获取当前亮度、最大亮度、最小亮度
• 调节亮度【用到了亮度曲线 从伽马曲线】
• 发送亮度控制的Intent
  的接受者【实际为BrightnessDialog】

声音音量也是一样的，在这个方法中进行了处理一次，再响应给View来处理