Android 电源键事件流程分析

Android 电源键事件流程分析

电源按键流程处理逻辑在 PhoneWindowManager.java类中的 dispatchUnhandledKey 方法中

frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java

从dispatchUnhandledKey方法开始分析

    @Overridepublic KeyEvent dispatchUnhandledKey(IBinder focusedToken, KeyEvent event, int policyFlags) {// Note: This method is only called if the initial down was unhandled.if (DEBUG_INPUT) {final KeyInterceptionInfo info =mWindowManagerInternal.getKeyInterceptionInfoFromToken(focusedToken);final String title = info == null ? "<unknown>" : info.windowTitle;Slog.d(TAG, "Unhandled key: inputToken=" + focusedToken+ ", title=" + title+ ", action=" + event.getAction()+ ", flags=" + event.getFlags()+ ", keyCode=" + event.getKeyCode()+ ", scanCode=" + event.getScanCode()+ ", metaState=" + event.getMetaState()+ ", repeatCount=" + event.getRepeatCount()+ ", policyFlags=" + policyFlags);}KeyEvent fallbackEvent = null;if ((event.getFlags() & KeyEvent.FLAG_FALLBACK) == 0) {final KeyCharacterMap kcm = event.getKeyCharacterMap();final int keyCode = event.getKeyCode();final int metaState = event.getMetaState();final boolean initialDown = event.getAction() == KeyEvent.ACTION_DOWN&& event.getRepeatCount() == 0;// Check for fallback actions specified by the key character map.final FallbackAction fallbackAction;if (initialDown) {fallbackAction = kcm.getFallbackAction(keyCode, metaState);} else {fallbackAction = mFallbackActions.get(keyCode);}if (fallbackAction != null) {if (DEBUG_INPUT) {Slog.d(TAG, "Fallback: keyCode=" + fallbackAction.keyCode+ " metaState=" + Integer.toHexString(fallbackAction.metaState));}final int flags = event.getFlags() | KeyEvent.FLAG_FALLBACK;fallbackEvent = KeyEvent.obtain(event.getDownTime(), event.getEventTime(),event.getAction(), fallbackAction.keyCode,event.getRepeatCount(), fallbackAction.metaState,event.getDeviceId(), event.getScanCode(),flags, event.getSource(), event.getDisplayId(), null);//核心代码if (!interceptFallback(focusedToken, fallbackEvent, policyFlags)) {fallbackEvent.recycle();fallbackEvent = null;}if (initialDown) {mFallbackActions.put(keyCode, fallbackAction);} else if (event.getAction() == KeyEvent.ACTION_UP) {mFallbackActions.remove(keyCode);fallbackAction.recycle();}}}if (DEBUG_INPUT) {if (fallbackEvent == null) {Slog.d(TAG, "No fallback.");} else {Slog.d(TAG, "Performing fallback: " + fallbackEvent);}}return fallbackEvent;}

关于电源按键的核心逻辑在interceptFallback方法里的interceptKeyBeforeQueueing方法里

   @Overridepublic int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {...if (!mSystemBooted) {// If we have not yet booted, don't let key events do anything.// Exception: Wake and power key events are forwarded to PowerManager to allow it to// wake from quiescent mode during boot.if (down && (keyCode == KeyEvent.KEYCODE_POWER|| keyCode == KeyEvent.KEYCODE_TV_POWER)) {wakeUpFromPowerKey(event.getDownTime());} else if (down && (isWakeKey || keyCode == KeyEvent.KEYCODE_WAKEUP)&& isWakeKeyWhenScreenOff(keyCode)) {wakeUpFromWakeKey(event);}return 0;}....// Handle special keys.switch (keyCode) {...case KeyEvent.KEYCODE_POWER: {EventLogTags.writeInterceptPower(KeyEvent.actionToString(event.getAction()),mPowerKeyHandled ? 1 : 0,mSingleKeyGestureDetector.getKeyPressCounter(KeyEvent.KEYCODE_POWER));// Any activity on the power button stops the accessibility shortcutresult &= ~ACTION_PASS_TO_USER;isWakeKey = false; // wake-up will be handled separatelyif (down) {interceptPowerKeyDown(event, interactiveAndOn);} else {interceptPowerKeyUp(event, canceled);}break;}}}return result;}

当按下的时候，执行interceptPowerKeyDown方法

private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {// Hold a wake lock until the power key is released.if (!mPowerKeyWakeLock.isHeld()) {mPowerKeyWakeLock.acquire();}mWindowManagerFuncs.onPowerKeyDown(interactive);// Stop ringing or end call if configured to do so when power is pressed.TelecomManager telecomManager = getTelecommService();boolean hungUp = false;if (telecomManager != null) {if (telecomManager.isRinging()) {// Pressing Power while there's a ringing incoming// call should silence the ringer.telecomManager.silenceRinger();} else if ((mIncallPowerBehavior& Settings.Secure.INCALL_POWER_BUTTON_BEHAVIOR_HANGUP) != 0&& telecomManager.isInCall() && interactive) {// Otherwise, if "Power button ends call" is enabled,// the Power button will hang up any current active call.hungUp = telecomManager.endCall();}}final boolean handledByPowerManager = mPowerManagerInternal.interceptPowerKeyDown(event);// Inform the StatusBar; but do not allow it to consume the event.sendSystemKeyToStatusBarAsync(event.getKeyCode());// If the power key has still not yet been handled, then detect short// press, long press, or multi press and decide what to do.mPowerKeyHandled = mPowerKeyHandled || hungUp|| handledByPowerManager || mKeyCombinationManager.isPowerKeyIntercepted();if (!mPowerKeyHandled) {if (!interactive) {wakeUpFromPowerKey(event.getDownTime());}} else {// handled by another power key policy.if (!mSingleKeyGestureDetector.isKeyIntercepted(KEYCODE_POWER)) {mSingleKeyGestureDetector.reset();}}}

1、Android 按电源键亮屏/息屏流程

1、亮屏

1.1、PhoneWindowManager.java 中的 interceptKeyBeforeQueueing 方法

    @Overridepublic int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {// Handle special keys.switch (keyCode) {case KeyEvent.KEYCODE_POWER: {EventLogTags.writeInterceptPower(KeyEvent.actionToString(event.getAction()),mPowerKeyHandled ? 1 : 0,mSingleKeyGestureDetector.getKeyPressCounter(KeyEvent.KEYCODE_POWER));// Any activity on the power button stops the accessibility shortcutresult &= ~ACTION_PASS_TO_USER;isWakeKey = false; // wake-up will be handled separatelyif (down) {// 按下power键调用interceptPowerKeyDown(event, interactiveAndOn);} else {interceptPowerKeyUp(event, canceled);}break;}}}

1.2、息屏时按下power键调用 interceptPowerKeyDown() 方法

private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {// Hold a wake lock until the power key is released.if (!mPowerKeyWakeLock.isHeld()) {mPowerKeyWakeLock.acquire();}mWindowManagerFuncs.onPowerKeyDown(interactive);// Stop ringing or end call if configured to do so when power is pressed.TelecomManager telecomManager = getTelecommService();boolean hungUp = false;if (telecomManager != null) {if (telecomManager.isRinging()) {// Pressing Power while there's a ringing incoming// call should silence the ringer.telecomManager.silenceRinger();} else if ((mIncallPowerBehavior& Settings.Secure.INCALL_POWER_BUTTON_BEHAVIOR_HANGUP) != 0&& telecomManager.isInCall() && interactive) {// Otherwise, if "Power button ends call" is enabled,// the Power button will hang up any current active call.hungUp = telecomManager.endCall();}}final boolean handledByPowerManager = mPowerManagerInternal.interceptPowerKeyDown(event);// Inform the StatusBar; but do not allow it to consume the event.sendSystemKeyToStatusBarAsync(event.getKeyCode());// If the power key has still not yet been handled, then detect short// press, long press, or multi press and decide what to do.mPowerKeyHandled = mPowerKeyHandled || hungUp|| handledByPowerManager || mKeyCombinationManager.isPowerKeyIntercepted();if (!mPowerKeyHandled) {if (!interactive) {// 表示当前未交互或者息屏状态下wakeUpFromPowerKey(event.getDownTime());}} else {// handled by another power key policy.if (!mSingleKeyGestureDetector.isKeyIntercepted(KEYCODE_POWER)) {mSingleKeyGestureDetector.reset();}}}

1.3、wakeUpFromPowerKey()

可以看到，在按下电源键的时候，如果判断，当前是息屏状态，则执行wakeUpFromPowerKey()方法，

private void wakeUpFromPowerKey(long eventTime) {if (wakeUp(eventTime, mAllowTheaterModeWakeFromPowerKey,PowerManager.WAKE_REASON_POWER_BUTTON, "android.policy:POWER")) {// Start HOME with "reason" extra if sleeping for more than mWakeUpToLastStateTimeoutif (shouldWakeUpWithHomeIntent()) {startDockOrHome(DEFAULT_DISPLAY, /*fromHomeKey*/ false, /*wakenFromDreams*/ true,PowerManager.wakeReasonToString(PowerManager.WAKE_REASON_POWER_BUTTON));}}
}

调用 wakeUp() 方法

private boolean wakeUp(long wakeTime, boolean wakeInTheaterMode, @WakeReason int reason,String details) {final boolean theaterModeEnabled = isTheaterModeEnabled();if (!wakeInTheaterMode && theaterModeEnabled) {return false;}if (theaterModeEnabled) {Settings.Global.putInt(mContext.getContentResolver(),Settings.Global.THEATER_MODE_ON, 0);}//核心代码mPowerManager.wakeUp(wakeTime, reason, details);return true;
}

1.4、PowerManager 中的 WakeUp() 方法

// android.os.PowerManager
public void wakeUp(long time, @WakeReason int reason, String details) {try {mService.wakeUp(time, reason, details, mContext.getOpPackageName());} catch (RemoteException e) {throw e.rethrowFromSystemServer();}
}

1.5、PowerManagerService 中 wakeUp() 方法

通过跨进程通信，我们知道真正的操作是在PowerManagerService类里的wakeUp()方法

@Override // Binder call
public void wakeUp(long eventTime, @WakeReason int reason, String details,String opPackageName) {if (eventTime > mClock.uptimeMillis()) {throw new IllegalArgumentException("event time must not be in the future");}mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);final int uid = Binder.getCallingUid();final long ident = Binder.clearCallingIdentity();try {wakeDisplayGroup(Display.DEFAULT_DISPLAY_GROUP, eventTime, reason, details, uid,opPackageName, uid);} finally {Binder.restoreCallingIdentity(ident);}
}

调用 wakeDisplayGroup() 方法

private void wakeDisplayGroup(int groupId, long eventTime, @WakeReason int reason,String details, int uid, String opPackageName, int opUid) {synchronized (mLock) {if (wakeDisplayGroupNoUpdateLocked(groupId, eventTime, reason, details, uid,opPackageName, opUid)) {updatePowerStateLocked();}}
}

1.6、先分析 wakeDisplayGroupNoUpdateLocked() 方法,如果它返回true，则执行updatePowerStateLocked方法

private boolean wakeDisplayGroupNoUpdateLocked(int groupId, long eventTime,@WakeReason int reason, String details, int uid, String opPackageName, int opUid) {if (DEBUG_SPEW) {Slog.d(TAG, "wakeDisplayGroupNoUpdateLocked: eventTime=" + eventTime+ ", groupId=" + groupId + ", uid=" + uid);}if (eventTime < mLastSleepTime || mForceSuspendActive || !mSystemReady) {return false;}final int currentState = mDisplayGroupPowerStateMapper.getWakefulnessLocked(groupId);if (currentState == WAKEFULNESS_AWAKE) {if (!mBootCompleted && sQuiescent) {mDirty |= DIRTY_QUIESCENT;return true;}return false;}Trace.traceBegin(Trace.TRACE_TAG_POWER, "powerOnDisplay");try {Slog.i(TAG, "Powering on display group from"+ PowerManagerInternal.wakefulnessToString(currentState)+ " (groupId=" + groupId+ ", uid=" + uid+ ", reason=" + PowerManager.wakeReasonToString(reason)+ ", details=" + details+ ")...");Trace.asyncTraceBegin(Trace.TRACE_TAG_POWER, TRACE_SCREEN_ON, groupId);//更新屏幕亮屏超时时间setWakefulnessLocked(groupId, WAKEFULNESS_AWAKE, eventTime, uid, reason, opUid,opPackageName, details);mDisplayGroupPowerStateMapper.setLastPowerOnTimeLocked(groupId, eventTime);mDisplayGroupPowerStateMapper.setPoweringOnLocked(groupId, true);} finally {Trace.traceEnd(Trace.TRACE_TAG_POWER);}return true;
}

先来看看setWakefulnessLocked方法

@VisibleForTesting
void setWakefulnessLocked(int groupId, int wakefulness, long eventTime, int uid, int reason,int opUid, String opPackageName, String details) {if (mDisplayGroupPowerStateMapper.setWakefulnessLocked(groupId, wakefulness)) {mDirty |= DIRTY_DISPLAY_GROUP_WAKEFULNESS;setGlobalWakefulnessLocked(mDisplayGroupPowerStateMapper.getGlobalWakefulnessLocked(),eventTime, reason, uid, opUid, opPackageName, details);if (wakefulness == WAKEFULNESS_AWAKE) {// Kick user activity to prevent newly awake group from timing out instantly.userActivityNoUpdateLocked(groupId, eventTime, PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, uid);}}
}

setGlobalWakefulnessLocked 方法

private void setGlobalWakefulnessLocked(int wakefulness, long eventTime, int reason, int uid,int opUid, String opPackageName, String details) {if (getWakefulnessLocked() == wakefulness) {return;}// Phase 1: Handle pre-wakefulness change bookkeeping.final String traceMethodName;switch (wakefulness) {case WAKEFULNESS_ASLEEP:traceMethodName = "reallyGoToSleep";Slog.i(TAG, "Sleeping (uid " + uid + ")...");break;case WAKEFULNESS_AWAKE:traceMethodName = "wakeUp";Slog.i(TAG, "Waking up from "+ PowerManagerInternal.wakefulnessToString(getWakefulnessLocked())+ " (uid=" + uid+ ", reason=" + PowerManager.wakeReasonToString(reason)+ ", details=" + details+ ")...");mLastWakeTime = eventTime;mLastWakeReason = reason;break;case WAKEFULNESS_DREAMING:traceMethodName = "nap";Slog.i(TAG, "Nap time (uid " + uid + ")...");break;case WAKEFULNESS_DOZING:traceMethodName = "goToSleep";Slog.i(TAG, "Going to sleep due to " + PowerManager.sleepReasonToString(reason)+ " (uid " + uid + ")...");mLastSleepTime = eventTime;mLastSleepReason = reason;mDozeStartInProgress = true;break;default:throw new IllegalArgumentException("Unexpected wakefulness: " + wakefulness);}Trace.traceBegin(Trace.TRACE_TAG_POWER, traceMethodName);try {// Phase 2: Handle wakefulness change and bookkeeping.// Under lock, invalidate before set ensures caches won't return stale values.mInjector.invalidateIsInteractiveCaches();mWakefulnessRaw = wakefulness;mWakefulnessChanging = true;mDirty |= DIRTY_WAKEFULNESS;// This is only valid while we are in wakefulness dozing. Set to false otherwise.mDozeStartInProgress &= (getWakefulnessLocked() == WAKEFULNESS_DOZING);if (mNotifier != null) {mNotifier.onWakefulnessChangeStarted(wakefulness, reason, eventTime);}mAttentionDetector.onWakefulnessChangeStarted(wakefulness);// Phase 3: Handle post-wakefulness change bookkeeping.switch (wakefulness) {case WAKEFULNESS_AWAKE:mNotifier.onWakeUp(reason, details, uid, opPackageName, opUid);if (sQuiescent) {mDirty |= DIRTY_QUIESCENT;}break;case WAKEFULNESS_DOZING:// Report the number of wake locks that will be cleared by going to sleep.int numWakeLocksCleared = 0;final int numWakeLocks = mWakeLocks.size();for (int i = 0; i < numWakeLocks; i++) {final WakeLock wakeLock = mWakeLocks.get(i);switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {case PowerManager.FULL_WAKE_LOCK:case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:case PowerManager.SCREEN_DIM_WAKE_LOCK:numWakeLocksCleared += 1;break;}}EventLogTags.writePowerSleepRequested(numWakeLocksCleared);break;}} finally {Trace.traceEnd(Trace.TRACE_TAG_POWER);}
}

继续往下追，查看Notifier类里的onWakefulnessChangeStarted方法

//com.android.server.power.Notifier
/*** Notifies that the device is changing wakefulness.* This function may be called even if the previous change hasn't finished in* which case it will assume that the state did not fully converge before the* next transition began and will recover accordingly.*/
public void onWakefulnessChangeStarted(final int wakefulness, int reason, long eventTime) {final boolean interactive = PowerManagerInternal.isInteractive(wakefulness);if (DEBUG) {Slog.d(TAG, "onWakefulnessChangeStarted: wakefulness=" + wakefulness+ ", reason=" + reason + ", interactive=" + interactive);}// Tell the activity manager about changes in wakefulness, not just interactivity.// It needs more granularity than other components.mHandler.post(new Runnable() {@Overridepublic void run() {mActivityManagerInternal.onWakefulnessChanged(wakefulness);}});// Handle any early interactive state changes.// Finish pending incomplete ones from a previous cycle.if (mInteractive != interactive) {// Finish up late behaviors if needed.if (mInteractiveChanging) {handleLateInteractiveChange();}// Start input as soon as we start waking up or going to sleep.mInputManagerInternal.setInteractive(interactive);mInputMethodManagerInternal.setInteractive(interactive);// Notify battery stats.try {mBatteryStats.noteInteractive(interactive);} catch (RemoteException ex) { }FrameworkStatsLog.write(FrameworkStatsLog.INTERACTIVE_STATE_CHANGED,interactive ? FrameworkStatsLog.INTERACTIVE_STATE_CHANGED__STATE__ON :FrameworkStatsLog.INTERACTIVE_STATE_CHANGED__STATE__OFF);// Handle early behaviors.mInteractive = interactive;mInteractiveChangeReason = reason;mInteractiveChangeStartTime = eventTime;mInteractiveChanging = true;handleEarlyInteractiveChange();}
}

继续看 handleEarlyInteractiveChange方法

/*** Handle early interactive state changes such as getting applications or the lock* screen running and ready for the user to see (such as when turning on the screen).*/
private void handleEarlyInteractiveChange() {synchronized (mLock) {if (mInteractive) {// Waking up...mHandler.post(() -> mPolicy.startedWakingUp(mInteractiveChangeReason));// Send interactive broadcast.mPendingInteractiveState = INTERACTIVE_STATE_AWAKE;mPendingWakeUpBroadcast = true;updatePendingBroadcastLocked();} else {// Going to sleep...// Tell the policy that we started going to sleep.mHandler.post(() -> mPolicy.startedGoingToSleep(mInteractiveChangeReason));}}
}

继续看 updatePendingBroadcastLocked 方法

private void updatePendingBroadcastLocked() {if (!mBroadcastInProgress&& mPendingInteractiveState != INTERACTIVE_STATE_UNKNOWN&& (mPendingWakeUpBroadcast || mPendingGoToSleepBroadcast|| mPendingInteractiveState != mBroadcastedInteractiveState)) {mBroadcastInProgress = true;mSuspendBlocker.acquire();//发送广播Message msg = mHandler.obtainMessage(MSG_BROADCAST);msg.setAsynchronous(true);mHandler.sendMessage(msg);}
}

继续看 Handler 调用的方法

private final class NotifierHandler extends Handler {public NotifierHandler(Looper looper) {super(looper, null, true /*async*/);}@Overridepublic void handleMessage(Message msg) {switch (msg.what) {...case MSG_BROADCAST:sendNextBroadcast();break;....}}
}

在 sendNextBroadcast() 方法中 调用了 sendWakeUpBroadcast() 方法

private void sendWakeUpBroadcast() {if (DEBUG) {Slog.d(TAG, "Sending wake up broadcast.");}if (mActivityManagerInternal.isSystemReady()) {mContext.sendOrderedBroadcastAsUser(mScreenOnIntent, UserHandle.ALL, null,mWakeUpBroadcastDone, mHandler, 0, null, null);} else {EventLog.writeEvent(EventLogTags.POWER_SCREEN_BROADCAST_STOP, 2, 1);sendNextBroadcast();}
}

1.7、在 分析 updatePowerStateLocked 方法，此方法目的是更新PackageManagerService全局状态

/*** Updates the global power state based on dirty bits recorded in mDirty.** This is the main function that performs power state transitions.* We centralize them here so that we can recompute the power state completely* each time something important changes, and ensure that we do it the same* way each time.  The point is to gather all of the transition logic here.*/
private void updatePowerStateLocked() {if (!mSystemReady || mDirty == 0) {return;}if (!Thread.holdsLock(mLock)) {Slog.wtf(TAG, "Power manager lock was not held when calling updatePowerStateLocked");}Trace.traceBegin(Trace.TRACE_TAG_POWER, "updatePowerState");try {// Phase 0: Basic state updates.updateIsPoweredLocked(mDirty);updateStayOnLocked(mDirty);updateScreenBrightnessBoostLocked(mDirty);// Phase 1: Update wakefulness.// Loop because the wake lock and user activity computations are influenced// by changes in wakefulness.final long now = mClock.uptimeMillis();int dirtyPhase2 = 0;for (;;) {int dirtyPhase1 = mDirty;dirtyPhase2 |= dirtyPhase1;mDirty = 0;updateWakeLockSummaryLocked(dirtyPhase1);updateUserActivitySummaryLocked(now, dirtyPhase1);updateAttentiveStateLocked(now, dirtyPhase1);if (!updateWakefulnessLocked(dirtyPhase1)) {break;}}// Phase 2: Lock profiles that became inactive/not kept awake.updateProfilesLocked(now);// Phase 3: Update display power state./*** 异步更新显示器电源状态。更新完成后，mDisplayReady 将设置为 true。显示控制器会发布一条消息，告诉我们实际显示电源状态何时		 * 更新，因此我们回到这里仔细检查并完成。此功能每次重新计算显示器电源状态。返回：如果显示已准备好，则为true。* 经过这一步后，会将系统的亮度、显示状态等全部设置完毕，此时屏幕已经亮了*/final boolean displayBecameReady = updateDisplayPowerStateLocked(dirtyPhase2);// Phase 4: Update dream state (depends on display ready signal).updateDreamLocked(dirtyPhase2, displayBecameReady);// Phase 5: Send notifications, if needed.finishWakefulnessChangeIfNeededLocked();// Phase 6: Update suspend blocker.// Because we might release the last suspend blocker here, we need to make sure// we finished everything else first!updateSuspendBlockerLocked();} finally {Trace.traceEnd(Trace.TRACE_TAG_POWER);}
}

再分析finishWakefulnessChangeIfNeededLocked() 方法，看看亮屏收尾工作都做了那些

private void finishWakefulnessChangeIfNeededLocked() {if (mWakefulnessChanging && mDisplayGroupPowerStateMapper.areAllDisplaysReadyLocked()) {if (getWakefulnessLocked() == WAKEFULNESS_DOZING&& (mWakeLockSummary & WAKE_LOCK_DOZE) == 0) {return; // wait until dream has enabled dozing} else {// Doze wakelock acquired (doze started) or device is no longer dozing.mDozeStartInProgress = false;}if (getWakefulnessLocked() == WAKEFULNESS_DOZING|| getWakefulnessLocked() == WAKEFULNESS_ASLEEP) {logSleepTimeoutRecapturedLocked();}mWakefulnessChanging = false;mNotifier.onWakefulnessChangeFinished();}
}

继续看 Notifier类里的onWakefulnessChangeFinished() 方法

//com.android.server.power.Notifier
/*** Notifies that the device has finished changing wakefulness.*/
public void onWakefulnessChangeFinished() {if (DEBUG) {Slog.d(TAG, "onWakefulnessChangeFinished");}if (mInteractiveChanging) {mInteractiveChanging = false;handleLateInteractiveChange();}
}

看调用的handleLateInteractiveChange() 方法

/*** Handle late interactive state changes once they are finished so that the system can* finish pending transitions (such as turning the screen off) before causing* applications to change state visibly.*/
private void handleLateInteractiveChange() {synchronized (mLock) {final int interactiveChangeLatency =(int) (SystemClock.uptimeMillis() - mInteractiveChangeStartTime);if (mInteractive) {// Finished waking up...mHandler.post(() -> {LogMaker log = new LogMaker(MetricsEvent.SCREEN);log.setType(MetricsEvent.TYPE_OPEN);log.setSubtype(WindowManagerPolicyConstants.translateWakeReasonToOnReason(mInteractiveChangeReason));log.setLatency(interactiveChangeLatency);log.addTaggedData(MetricsEvent.FIELD_SCREEN_WAKE_REASON, mInteractiveChangeReason);MetricsLogger.action(log);EventLogTags.writePowerScreenState(1, 0, 0, 0, interactiveChangeLatency);//通知PhoneWindowManager唤醒操作结束mPolicy.finishedWakingUp(mInteractiveChangeReason);});} else {.....}}
}

2、息屏

同唤醒操作，首先执行PhoneWindowManager.java中的 interceptKeyBeforeQueueing() 方法中 KEYCODE_POWER

@Override
public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {....// Handle special keys.switch (keyCode) {....case KeyEvent.KEYCODE_POWER: {EventLogTags.writeInterceptPower(KeyEvent.actionToString(event.getAction()),mPowerKeyHandled ? 1 : 0,mSingleKeyGestureDetector.getKeyPressCounter(KeyEvent.KEYCODE_POWER));// Any activity on the power button stops the accessibility shortcutresult &= ~ACTION_PASS_TO_USER;isWakeKey = false; // wake-up will be handled separatelyif (down) {interceptPowerKeyDown(event, interactiveAndOn);} else {//手指抬起interceptPowerKeyUp(event, canceled);}break;}}....return result;
}private void interceptPowerKeyUp(KeyEvent event, boolean canceled) {final boolean handled = canceled || mPowerKeyHandled;if (!handled) {if ((event.getFlags() & KeyEvent.FLAG_LONG_PRESS) == 0) {// Abort possibly stuck animations only when power key up without long press case.mHandler.post(mWindowManagerFuncs::triggerAnimationFailsafe);}} else {// handled by single key or another power key policy.if (!mSingleKeyGestureDetector.isKeyIntercepted(KEYCODE_POWER)) {mSingleKeyGestureDetector.reset();}}finishPowerKeyPress();
}

再 PhoneWindowManager 类中 init() 方法中调用了 initSingleKeyGestureRules() -> PowerKeyRule() -> powerPress()

private void powerPress(long eventTime, int count, boolean beganFromNonInteractive) {if (mDefaultDisplayPolicy.isScreenOnEarly() && !mDefaultDisplayPolicy.isScreenOnFully()) {Slog.i(TAG, "Suppressed redundant power key press while "+ "already in the process of turning the screen on.");return;}final boolean interactive = Display.isOnState(mDefaultDisplay.getState());Slog.d(TAG, "powerPress: eventTime=" + eventTime + " interactive=" + interactive+ " count=" + count + " beganFromNonInteractive=" + beganFromNonInteractive+ " mShortPressOnPowerBehavior=" + mShortPressOnPowerBehavior);if (count == 2) {powerMultiPressAction(eventTime, interactive, mDoublePressOnPowerBehavior);} else if (count == 3) {powerMultiPressAction(eventTime, interactive, mTriplePressOnPowerBehavior);} else if (interactive && !beganFromNonInteractive) {if (mSideFpsEventHandler.onSinglePressDetected(eventTime)) {Slog.i(TAG, "Suppressing power key because the user is interacting with the "+ "fingerprint sensor");return;}switch (mShortPressOnPowerBehavior) {case SHORT_PRESS_POWER_NOTHING:break;case SHORT_PRESS_POWER_GO_TO_SLEEP:sleepDefaultDisplayFromPowerButton(eventTime, 0);break;case SHORT_PRESS_POWER_REALLY_GO_TO_SLEEP:sleepDefaultDisplayFromPowerButton(eventTime,PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE);break;.....}}
}

查看 mShortPressOnPowerBehavior 赋值

mShortPressOnPowerBehavior = mContext.getResources().getInteger(com.android.internal.R.integer.config_shortPressOnPowerBehavior);//查看配置文件
<!-- Control the behavior when the user short presses the power button.0 - Nothing1 - Go to sleep (doze)2 - Really go to sleep (don't doze)3 - Really go to sleep and go home (don't doze)4 - Go to home5 - Dismiss IME if shown. Otherwise go to home
-->
<integer name="config_shortPressOnPowerBehavior">1</integer>

执行 case SHORT_PRESS_POWER_GO_TO_SLEEP 方法，即 sleepDefaultDisplayFromPowerButton()

/*** Sends the default display to sleep as a result of a power button press.** @return {@code true} if the device was sent to sleep, {@code false} if the device did not* sleep.*/
//由于按下电源按钮，设备进入睡眠状态。返回：如果设备被发送到睡眠状态，则返回 true，如果睡眠被抑制，则返回 false
private boolean sleepDefaultDisplayFromPowerButton(long eventTime, int flags) {// Before we actually go to sleep, we check the last wakeup reason.// If the device very recently woke up from a gesture (like user lifting their device)// then ignore the sleep instruction. This is because users have developed// a tendency to hit the power button immediately when they pick up their device, and we// don't want to put the device back to sleep in those cases.final PowerManager.WakeData lastWakeUp = mPowerManagerInternal.getLastWakeup();if (lastWakeUp != null && lastWakeUp.wakeReason == PowerManager.WAKE_REASON_GESTURE) {final int gestureDelayMillis = Settings.Global.getInt(mContext.getContentResolver(),Settings.Global.POWER_BUTTON_SUPPRESSION_DELAY_AFTER_GESTURE_WAKE,POWER_BUTTON_SUPPRESSION_DELAY_DEFAULT_MILLIS);final long now = SystemClock.uptimeMillis();if (mPowerButtonSuppressionDelayMillis > 0&& (now < lastWakeUp.wakeTime + mPowerButtonSuppressionDelayMillis)) {Slog.i(TAG, "Sleep from power button suppressed. Time since gesture: "+ (now - lastWakeUp.wakeTime) + "ms");return false;}}sleepDefaultDisplay(eventTime, PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON, flags);return true;
}

private void sleepDefaultDisplay(long eventTime, int reason, int flags) {mRequestedOrSleepingDefaultDisplay = true;mPowerManager.goToSleep(eventTime, reason, flags);
}

继续往下追PowerManagerService 的goToSleep()

@Override // Binder call
public void goToSleep(long eventTime, int reason, int flags) {if (eventTime > mClock.uptimeMillis()) {throw new IllegalArgumentException("event time must not be in the future");}mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);final int uid = Binder.getCallingUid();final long ident = Binder.clearCallingIdentity();try {sleepDisplayGroup(Display.DEFAULT_DISPLAY_GROUP, eventTime, reason, flags, uid);} finally {Binder.restoreCallingIdentity(ident);}
}private void sleepDisplayGroup(int groupId, long eventTime, int reason, int flags,int uid) {synchronized (mLock) {if (sleepDisplayGroupNoUpdateLocked(groupId, eventTime, reason, flags, uid)) {updatePowerStateLocked();	}}
}

先分析 sleepDisplayGroupNoUpdateLocked()

private boolean sleepDisplayGroupNoUpdateLocked(int groupId, long eventTime, int reason,int flags, int uid) {if (DEBUG_SPEW) {Slog.d(TAG, "sleepDisplayGroupNoUpdateLocked: eventTime=" + eventTime+ ", groupId=" + groupId + ", reason=" + reason + ", flags=" + flags+ ", uid=" + uid);}if (eventTime < mLastWakeTime|| !PowerManagerInternal.isInteractive(getWakefulnessLocked())|| !mSystemReady|| !mBootCompleted) {return false;}final int wakefulness = mDisplayGroupPowerStateMapper.getWakefulnessLocked(groupId);if (!PowerManagerInternal.isInteractive(wakefulness)) {return false;}Trace.traceBegin(Trace.TRACE_TAG_POWER, "powerOffDisplay");try {reason = Math.min(PowerManager.GO_TO_SLEEP_REASON_MAX,Math.max(reason, PowerManager.GO_TO_SLEEP_REASON_MIN));Slog.i(TAG, "Powering off display group due to "+ PowerManager.sleepReasonToString(reason) + " (groupId= " + groupId+ ", uid= " + uid + ")...");mDisplayGroupPowerStateMapper.setSandmanSummoned(groupId, true);//核心代码setWakefulnessLocked(groupId, WAKEFULNESS_DOZING, eventTime, uid, reason,/* opUid= */ 0, /* opPackageName= */ null, /* details= */ null);if ((flags & PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE) != 0) {reallySleepDisplayGroupNoUpdateLocked(groupId, eventTime, uid);}} finally {Trace.traceEnd(Trace.TRACE_TAG_POWER);}return true;
}

由setWakefulnessLocked() -> setGlobalWakefulnessLocked() -> mNotifier.onWakefulnessChangeStarted()

同wakeup一样，会走到Notifer类的onWakefulnessChangeStarted()方法

/*** Notifies that the device is changing wakefulness.* This function may be called even if the previous change hasn't finished in* which case it will assume that the state did not fully converge before the* next transition began and will recover accordingly.*/
public void onWakefulnessChangeStarted(final int wakefulness, int reason, long eventTime) {final boolean interactive = PowerManagerInternal.isInteractive(wakefulness);if (DEBUG) {Slog.d(TAG, "onWakefulnessChangeStarted: wakefulness=" + wakefulness+ ", reason=" + reason + ", interactive=" + interactive);}// Tell the activity manager about changes in wakefulness, not just interactivity.// It needs more granularity than other components.mHandler.post(new Runnable() {@Overridepublic void run() {mActivityManagerInternal.onWakefulnessChanged(wakefulness);}});// Handle any early interactive state changes.// Finish pending incomplete ones from a previous cycle.if (mInteractive != interactive) {// Finish up late behaviors if needed.if (mInteractiveChanging) {handleLateInteractiveChange();}// Start input as soon as we start waking up or going to sleep.mInputManagerInternal.setInteractive(interactive);mInputMethodManagerInternal.setInteractive(interactive);// Notify battery stats.try {mBatteryStats.noteInteractive(interactive);} catch (RemoteException ex) { }FrameworkStatsLog.write(FrameworkStatsLog.INTERACTIVE_STATE_CHANGED,interactive ? FrameworkStatsLog.INTERACTIVE_STATE_CHANGED__STATE__ON :FrameworkStatsLog.INTERACTIVE_STATE_CHANGED__STATE__OFF);// Handle early behaviors.mInteractive = interactive;mInteractiveChangeReason = reason;mInteractiveChangeStartTime = eventTime;mInteractiveChanging = true;handleEarlyInteractiveChange();}
}

继续看 handleErarlyInteractiveChange 方法

/*** Handle early interactive state changes such as getting applications or the lock* screen running and ready for the user to see (such as when turning on the screen).*/
private void handleEarlyInteractiveChange() {synchronized (mLock) {if (mInteractive) {// Waking up...mHandler.post(() -> mPolicy.startedWakingUp(mInteractiveChangeReason));// Send interactive broadcast.mPendingInteractiveState = INTERACTIVE_STATE_AWAKE;mPendingWakeUpBroadcast = true;updatePendingBroadcastLocked();} else {// Going to sleep...// Tell the policy that we started going to sleep.mHandler.post(() -> mPolicy.startedGoingToSleep(mInteractiveChangeReason));}}
}

再分析 updatePowerStateLocked()， 唤醒的时候，也会走到这里

/*** Updates the global power state based on dirty bits recorded in mDirty.** This is the main function that performs power state transitions.* We centralize them here so that we can recompute the power state completely* each time something important changes, and ensure that we do it the same* way each time.  The point is to gather all of the transition logic here.*/
private void updatePowerStateLocked() {if (!mSystemReady || mDirty == 0) {return;}if (!Thread.holdsLock(mLock)) {Slog.wtf(TAG, "Power manager lock was not held when calling updatePowerStateLocked");}Trace.traceBegin(Trace.TRACE_TAG_POWER, "updatePowerState");try {// Phase 0: Basic state updates.updateIsPoweredLocked(mDirty);updateStayOnLocked(mDirty);updateScreenBrightnessBoostLocked(mDirty);// Phase 1: Update wakefulness.// Loop because the wake lock and user activity computations are influenced// by changes in wakefulness.final long now = mClock.uptimeMillis();int dirtyPhase2 = 0;for (;;) {int dirtyPhase1 = mDirty;dirtyPhase2 |= dirtyPhase1;mDirty = 0;updateWakeLockSummaryLocked(dirtyPhase1);updateUserActivitySummaryLocked(now, dirtyPhase1);updateAttentiveStateLocked(now, dirtyPhase1);if (!updateWakefulnessLocked(dirtyPhase1)) {break;}}// Phase 2: Lock profiles that became inactive/not kept awake.updateProfilesLocked(now);// Phase 3: Update display power state.final boolean displayBecameReady = updateDisplayPowerStateLocked(dirtyPhase2);// Phase 4: Update dream state (depends on display ready signal).updateDreamLocked(dirtyPhase2, displayBecameReady);// Phase 5: Send notifications, if needed.finishWakefulnessChangeIfNeededLocked();// Phase 6: Update suspend blocker.// Because we might release the last suspend blocker here, we need to make sure// we finished everything else first!updateSuspendBlockerLocked();} finally {Trace.traceEnd(Trace.TRACE_TAG_POWER);}
}

当息屏执行结束，我们分析finishWakefulnessChangeIfNeededLocked方法

private void finishWakefulnessChangeIfNeededLocked() {if (mWakefulnessChanging && mDisplayGroupPowerStateMapper.areAllDisplaysReadyLocked()) {if (getWakefulnessLocked() == WAKEFULNESS_DOZING&& (mWakeLockSummary & WAKE_LOCK_DOZE) == 0) {return; // wait until dream has enabled dozing} else {// Doze wakelock acquired (doze started) or device is no longer dozing.mDozeStartInProgress = false;}if (getWakefulnessLocked() == WAKEFULNESS_DOZING|| getWakefulnessLocked() == WAKEFULNESS_ASLEEP) {logSleepTimeoutRecapturedLocked();}mWakefulnessChanging = false;mNotifier.onWakefulnessChangeFinished();}
}

我们继续来分析Notifier类的onWakefulnessChangeFinished方法

/*** Notifies that the device has finished changing wakefulness.*/
public void onWakefulnessChangeFinished() {if (DEBUG) {Slog.d(TAG, "onWakefulnessChangeFinished");}if (mInteractiveChanging) {mInteractiveChanging = false;handleLateInteractiveChange();}
}

/*** Handle late interactive state changes once they are finished so that the system can* finish pending transitions (such as turning the screen off) before causing* applications to change state visibly.*/
private void handleLateInteractiveChange() {synchronized (mLock) {final int interactiveChangeLatency =(int) (SystemClock.uptimeMillis() - mInteractiveChangeStartTime);if (mInteractive) {// Finished waking up...mHandler.post(() -> {LogMaker log = new LogMaker(MetricsEvent.SCREEN);log.setType(MetricsEvent.TYPE_OPEN);log.setSubtype(WindowManagerPolicyConstants.translateWakeReasonToOnReason(mInteractiveChangeReason));log.setLatency(interactiveChangeLatency);log.addTaggedData(MetricsEvent.FIELD_SCREEN_WAKE_REASON, mInteractiveChangeReason);MetricsLogger.action(log);EventLogTags.writePowerScreenState(1, 0, 0, 0, interactiveChangeLatency);mPolicy.finishedWakingUp(mInteractiveChangeReason);});} else {// Finished going to sleep...// This is a good time to make transitions that we don't want the user to see,// such as bringing the key guard to focus.  There's no guarantee for this// however because the user could turn the device on again at any time.// Some things may need to be protected by other mechanisms that defer screen on.// Cancel pending user activity.if (mUserActivityPending) {mUserActivityPending = false;mHandler.removeMessages(MSG_USER_ACTIVITY);}// Tell the policy we finished going to sleep.final int offReason = WindowManagerPolicyConstants.translateSleepReasonToOffReason(mInteractiveChangeReason);mHandler.post(() -> {LogMaker log = new LogMaker(MetricsEvent.SCREEN);log.setType(MetricsEvent.TYPE_CLOSE);log.setSubtype(offReason);log.setLatency(interactiveChangeLatency);log.addTaggedData(MetricsEvent.FIELD_SCREEN_SLEEP_REASON, mInteractiveChangeReason);MetricsLogger.action(log);EventLogTags.writePowerScreenState(0, offReason, 0, 0, interactiveChangeLatency);mPolicy.finishedGoingToSleep(mInteractiveChangeReason);});// Send non-interactive broadcast.mPendingInteractiveState = INTERACTIVE_STATE_ASLEEP;mPendingGoToSleepBroadcast = true;//发送息屏广播，和唤醒类似，就不再赘述了updatePendingBroadcastLocked();}}
}

好了，从我们分析源码得知
唤醒的时候，唤醒广播是在handleEarlyInteractiveChange方法，就是在通知PhoneWindowManager 去执行startedWakingUp方法，紧跟着就执行updatePendingBroadcastLocked方法，去发送唤醒广播
而在息屏的时候，在handleEarlyInteractiveChange里，我们只是通知PhoneWindowManager去执行startedGoingToSleep方法，最后在updatePowerStateLocked==>finishWakefulnessChangeIfNeededLocked==>Notifier==>onWakefulnessChangeFinished==》handleLateInteractiveChange方法里，在通知PhoneWindowManager执行finishedGoingToSleep()之后，才执行updatePendingBroadcastLocked()方法去发送息屏广播(Intent.ACTION_SCREEN_OFF)，这个时机需要特别注意一下。

参考 : https://blog.csdn.net/jwg1988/article/details/123899706

2、长按Power事件

2.1、PhoneWindowManager.java -> powerLongPress() 方法

private void powerLongPress(long eventTime) {final int behavior = getResolvedLongPressOnPowerBehavior();Slog.d(TAG, "powerLongPress: eventTime=" + eventTime+ " mLongPressOnPowerBehavior=" + mLongPressOnPowerBehavior);switch (behavior) {case LONG_PRESS_POWER_NOTHING:break;case LONG_PRESS_POWER_GLOBAL_ACTIONS:mPowerKeyHandled = true;performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, false,"Power - Long Press - Global Actions");showGlobalActions();break;case LONG_PRESS_POWER_SHUT_OFF:case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:mPowerKeyHandled = true;performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, false,"Power - Long Press - Shut Off");sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);break;case LONG_PRESS_POWER_GO_TO_VOICE_ASSIST:mPowerKeyHandled = true;performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, false,"Power - Long Press - Go To Voice Assist");// Some devices allow the voice assistant intent during setup (and use that intent// to launch something else, like Settings). So we explicitly allow that via the// config_allowStartActivityForLongPressOnPowerInSetup resource in config.xml.launchVoiceAssist(mAllowStartActivityForLongPressOnPowerDuringSetup);break;case LONG_PRESS_POWER_ASSISTANT:mPowerKeyHandled = true;performHapticFeedback(HapticFeedbackConstants.ASSISTANT_BUTTON, false,"Power - Long Press - Go To Assistant");final int powerKeyDeviceId = Integer.MIN_VALUE;launchAssistAction(null, powerKeyDeviceId, eventTime,AssistUtils.INVOCATION_TYPE_POWER_BUTTON_LONG_PRESS);break;}
}

2.2、getResolvedLongPressOnPowerBehavior()

解析长按电源键行为的方法

private int getResolvedLongPressOnPowerBehavior() {if (FactoryTest.isLongPressOnPowerOffEnabled()) {return LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM;}// If the config indicates the assistant behavior but the device isn't yet provisioned, show// global actions instead.if (mLongPressOnPowerBehavior == LONG_PRESS_POWER_ASSISTANT && !isDeviceProvisioned()) {return LONG_PRESS_POWER_GLOBAL_ACTIONS;}return mLongPressOnPowerBehavior; //最后返回这个行为
}

而 mLongPressOnPowerBehavior 在init()方法中调用的是资源文件

mLongPressOnPowerBehavior = mContext.getResources().getInteger(com.android.internal.R.integer.config_longPressOnPowerBehavior);

默认配置文件中

    <!-- Control the behavior when the user long presses the power button.0 - Nothing1 - Global actions menu2 - Power off (with confirmation)3 - Power off (without confirmation)4 - Go to voice assist5 - Go to assistant (Settings.Secure.ASSISTANT)--><integer name="config_longPressOnPowerBehavior">5</integer>  //可以看到默认值为5

但在overlay中设置的内容默认值为1

 /os/la.qssi12/vendor/qcom/proprietary/commonsys/resource-overlay/common/Frameworks/res/values/config.xml 
<integer name="config_longPressOnPowerBehavior">1</integer>

2.3、showGlobalActions()

设置的 config_longPressOnPowerBehavior = 1；在powerLongPress方法中走 LONG_PRESS_POWER_GLOBAL_ACTIONS，调用 showGlobalActions()

@Override
public void showGlobalActions() {mHandler.removeMessages(MSG_DISPATCH_SHOW_GLOBAL_ACTIONS);mHandler.sendEmptyMessage(MSG_DISPATCH_SHOW_GLOBAL_ACTIONS);
}

2.4、showGlobalActionsInternal()

MSG_DISPATCH_SHOW_GLOBAL_ACTIONS -> showGlobalActionsInternal()

void showGlobalActionsInternal() {if (mGlobalActions == null) {mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);}final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned());// since it took two seconds of long press to bring this up,// poke the wake lock so they have some time to see the dialog.mPowerManager.userActivity(SystemClock.uptimeMillis(), false);
}

2.5、showDialog()

//com.android.server.policy.GlobalActions
public void showDialog(boolean keyguardShowing, boolean deviceProvisioned) {if (DEBUG) Slog.d(TAG, "showDialog " + keyguardShowing + " " + deviceProvisioned);if (mGlobalActionsProvider != null && mGlobalActionsProvider.isGlobalActionsDisabled()) {return;}mKeyguardShowing = keyguardShowing;mDeviceProvisioned = deviceProvisioned;mShowing = true;if (mGlobalActionsAvailable) {mHandler.postDelayed(mShowTimeout, 5000);mGlobalActionsProvider.showGlobalActions();} else {// SysUI isn't alive, show legacy menu.ensureLegacyCreated();mLegacyGlobalActions.showDialog(mKeyguardShowing, mDeviceProvisioned);}
}

2.6、mLegacyGlobalActions.showDialog()

//com.android.server.policy.LegacyGlobalActions
/*** Show the global actions dialog (creating if necessary)* @param keyguardShowing True if keyguard is showing*/
public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {mKeyguardShowing = keyguardShowing;mDeviceProvisioned = isDeviceProvisioned;if (mDialog != null) {mDialog.dismiss();mDialog = null;// Show delayed, so that the dismiss of the previous dialog completesmHandler.sendEmptyMessage(MESSAGE_SHOW);} else {handleShow();}
}

private void handleShow() {awakenIfNecessary();mDialog = createDialog();prepareDialog();// If we only have 1 item and it's a simple press action, just do this action.if (mAdapter.getCount() == 1&& mAdapter.getItem(0) instanceof SinglePressAction&& !(mAdapter.getItem(0) instanceof LongPressAction)) {((SinglePressAction) mAdapter.getItem(0)).onPress();} else {if (mDialog != null) {WindowManager.LayoutParams attrs = mDialog.getWindow().getAttributes();attrs.setTitle("LegacyGlobalActions");mDialog.getWindow().setAttributes(attrs);mDialog.show();mDialog.getWindow().getDecorView().setSystemUiVisibility(View.STATUS_BAR_DISABLE_EXPAND);}}
}

2.7、createDialog() 创建dialog

/*** Create the global actions dialog.* @return A new dialog.*/
private ActionsDialog createDialog() {// Simple toggle style if there's no vibrator, otherwise use a tri-stateif (!mHasVibrator) {mSilentModeAction = new SilentModeToggleAction();} else {mSilentModeAction = new SilentModeTriStateAction(mContext, mAudioManager, mHandler);}mAirplaneModeOn = new ToggleAction(R.drawable.ic_lock_airplane_mode,R.drawable.ic_lock_airplane_mode_off,R.string.global_actions_toggle_airplane_mode,R.string.global_actions_airplane_mode_on_status,R.string.global_actions_airplane_mode_off_status) {@Overridepublic void onToggle(boolean on) {if (mHasTelephony && TelephonyProperties.in_ecm_mode().orElse(false)) {mIsWaitingForEcmExit = true;// Launch ECM exit dialogIntent ecmDialogIntent =new Intent(TelephonyManager.ACTION_SHOW_NOTICE_ECM_BLOCK_OTHERS, null);ecmDialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);mContext.startActivity(ecmDialogIntent);} else {changeAirplaneModeSystemSetting(on);}}@Overrideprotected void changeStateFromPress(boolean buttonOn) {if (!mHasTelephony) return;// In ECM mode airplane state cannot be changedif (!TelephonyProperties.in_ecm_mode().orElse(false)) {mState = buttonOn ? State.TurningOn : State.TurningOff;mAirplaneState = mState;}}@Overridepublic boolean showDuringKeyguard() {return true;}@Overridepublic boolean showBeforeProvisioning() {return false;}};onAirplaneModeChanged();mItems = new ArrayList<Action>();String[] defaultActions = mContext.getResources().getStringArray(com.android.internal.R.array.config_globalActionsList);ArraySet<String> addedKeys = new ArraySet<String>();for (int i = 0; i < defaultActions.length; i++) {String actionKey = defaultActions[i];if (addedKeys.contains(actionKey)) {// If we already have added this, don't add it again.continue;}if (GLOBAL_ACTION_KEY_POWER.equals(actionKey)) {mItems.add(new PowerAction(mContext, mWindowManagerFuncs));} else if (GLOBAL_ACTION_KEY_AIRPLANE.equals(actionKey)) {mItems.add(mAirplaneModeOn);} else if (GLOBAL_ACTION_KEY_BUGREPORT.equals(actionKey)) {if (Settings.Global.getInt(mContext.getContentResolver(),Settings.Global.BUGREPORT_IN_POWER_MENU, 0) != 0 && isCurrentUserOwner()) {mItems.add(new BugReportAction());}} else if (GLOBAL_ACTION_KEY_SILENT.equals(actionKey)) {if (mShowSilentToggle) {mItems.add(mSilentModeAction);}} else if (GLOBAL_ACTION_KEY_USERS.equals(actionKey)) {if (SystemProperties.getBoolean("fw.power_user_switcher", false)) {addUsersToMenu(mItems);}} else if (GLOBAL_ACTION_KEY_SETTINGS.equals(actionKey)) {mItems.add(getSettingsAction());} else if (GLOBAL_ACTION_KEY_LOCKDOWN.equals(actionKey)) {mItems.add(getLockdownAction());} else if (GLOBAL_ACTION_KEY_VOICEASSIST.equals(actionKey)) {mItems.add(getVoiceAssistAction());} else if (GLOBAL_ACTION_KEY_ASSIST.equals(actionKey)) {mItems.add(getAssistAction());} else if (GLOBAL_ACTION_KEY_RESTART.equals(actionKey)) {mItems.add(new RestartAction(mContext, mWindowManagerFuncs));} else {Log.e(TAG, "Invalid global action key " + actionKey);}// Add here so we don't add more than one.addedKeys.add(actionKey);}if (mEmergencyAffordanceManager.needsEmergencyAffordance()) {mItems.add(getEmergencyAction());}mAdapter = new ActionsAdapter(mContext, mItems,() -> mDeviceProvisioned, () -> mKeyguardShowing);AlertController.AlertParams params = new AlertController.AlertParams(mContext);params.mAdapter = mAdapter;params.mOnClickListener = this;params.mForceInverseBackground = true;ActionsDialog dialog = new ActionsDialog(mContext, params);dialog.setCanceledOnTouchOutside(false); // Handled by the custom class.dialog.getListView().setItemsCanFocus(true);dialog.getListView().setLongClickable(true);dialog.getListView().setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {@Overridepublic boolean onItemLongClick(AdapterView<?> parent, View view, int position,long id) {final Action action = mAdapter.getItem(position);if (action instanceof LongPressAction) {return ((LongPressAction) action).onLongPress();}return false;}});dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);// Don't acquire soft keyboard focus, to avoid destroying state when capturing bugreportsdialog.getWindow().setFlags(FLAG_ALT_FOCUSABLE_IM, FLAG_ALT_FOCUSABLE_IM);dialog.setOnDismissListener(this);return dialog;
}

通过 String[] defaultActions = mContext.getResources().getStringArray(
com.android.internal.R.array.config_globalActionsList); 来查看配置文件

   <!-- Defines the default set of global actions. Actions may still be disabled or hidden basedon the current state of the device.Each item must be one of the following strings:"power" = Power off"settings" = An action to launch settings"airplane" = Airplane mode toggle"bugreport" = Take bug report, if available"silent" = silent mode"users" = list of users"restart" = restart device"emergency" = Launch emergency dialer"lockdown" = Lock down device until the user authenticates"logout" =  Logout the current user--><string-array translatable="false" name="config_globalActionsList"><item>emergency</item><item>lockdown</item><item>power</item><item>restart</item><item>logout</item><item>screenshot</item><item>bugreport</item></string-array>

最后展示出来，那么既然得到了关机界面，假如我们点击了其中的关机键，那么会如何执行呢

我们发现在构造弹框的时候

if (GLOBAL_ACTION_KEY_POWER.equals(actionKey)) {mItems.add(new PowerAction(mContext, mWindowManagerFuncs));}

那么点击item，就会执行PowerAction 的onPress()方法

@Override
public void onPress() {// shutdown by making sure radio and power are handled accordingly.mWindowManagerFuncs.shutdown(false /* confirm */);
}

mWindowManagerFuncs 由 PowerAction构造传进来的，往上追 ==> LegacyGlobalActions构造传入的 ==> GlobalActions构造传入 ==> PhoneWindowManager init()方法初始化的,最终我们是在WindowManagerService里找到PhoneWindowManager初始化的地方

//com.android.server.wm.WindowManagerService
private void initPolicy() {UiThread.getHandler().runWithScissors(new Runnable() {@Overridepublic void run() {WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper());mPolicy.init(mContext, WindowManagerService.this, WindowManagerService.this);}}, 0);
}

我们也知道其实mWindowManagerFuncs就是一个WindowManagerService对象，那么上面的shutdown其实是执行的是WindowManagerService的shutdown

// Called by window manager policy.  Not exposed externally.
@Override
public void shutdown(boolean confirm) {// Pass in the UI context, since ShutdownThread requires it (to show UI).ShutdownThread.shutdown(ActivityThread.currentActivityThread().getSystemUiContext(),PowerManager.SHUTDOWN_USER_REQUESTED, confirm);
}

继续往下追 ShutdownThread 类里的shutdown方法

/*** Request a clean shutdown, waiting for subsystems to clean up their* state etc.  Must be called from a Looper thread in which its UI* is shown.** @param context Context used to display the shutdown progress dialog. This must be a context*                suitable for displaying UI (aka Themable).* @param reason code to pass to android_reboot() (e.g. "userrequested"), or null.* @param confirm true if user confirmation is needed before shutting down.*/
public static void shutdown(final Context context, String reason, boolean confirm) {mReboot = false;mRebootSafeMode = false;mReason = reason;shutdownInner(context, confirm);
}

继续执行shutdownInner 方法

 private static void shutdownInner(final Context context, boolean confirm) {// ShutdownThread is called from many places, so best to verify here that the context passed// in is themed.context.assertRuntimeOverlayThemable();// ensure that only one thread is trying to power down.// any additional calls are just returnedsynchronized (sIsStartedGuard) {if (sIsStarted) {Log.d(TAG, "Request to shutdown already running, returning.");return;}}// Add checkpoint for this shutdown attempt. The user might still cancel the dialog, but// this point preserves the system trace of the trigger point of the ShutdownThread.ShutdownCheckPoints.recordCheckPoint(/* reason= */ null);final int longPressBehavior = context.getResources().getInteger(com.android.internal.R.integer.config_longPressOnPowerBehavior);final int resourceId = mRebootSafeMode? com.android.internal.R.string.reboot_safemode_confirm: (longPressBehavior == 2? com.android.internal.R.string.shutdown_confirm_question: com.android.internal.R.string.shutdown_confirm);Log.d(TAG, "Notifying thread to start shutdown longPressBehavior=" + longPressBehavior);if (confirm) {final CloseDialogReceiver closer = new CloseDialogReceiver(context);if (sConfirmDialog != null) {sConfirmDialog.dismiss();}sConfirmDialog = new AlertDialog.Builder(context).setTitle(mRebootSafeMode? com.android.internal.R.string.reboot_safemode_title: com.android.internal.R.string.power_off).setMessage(resourceId).setPositiveButton(com.android.internal.R.string.yes, new DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog, int which) {beginShutdownSequence(context);}}).setNegativeButton(com.android.internal.R.string.no, null).create();closer.dialog = sConfirmDialog;sConfirmDialog.setOnDismissListener(closer);sConfirmDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);sConfirmDialog.show();} else {beginShutdownSequence(context);}}

是否需要弹出关机确认框，如果需要则弹出，通过上面我们传入的是false，所以直接执行

2.8、beginShutdownSequence(context);

private static void beginShutdownSequence(Context context) {synchronized (sIsStartedGuard) {if (sIsStarted) {Log.d(TAG, "Shutdown sequence already running, returning.");return;}sIsStarted = true;}sInstance.mProgressDialog = showShutdownDialog(context);sInstance.mContext = context;sInstance.mPowerManager = (PowerManager)context.getSystemService(Context.POWER_SERVICE);// make sure we never fall asleep againsInstance.mCpuWakeLock = null;try {sInstance.mCpuWakeLock = sInstance.mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG + "-cpu");sInstance.mCpuWakeLock.setReferenceCounted(false);sInstance.mCpuWakeLock.acquire();} catch (SecurityException e) {Log.w(TAG, "No permission to acquire wake lock", e);sInstance.mCpuWakeLock = null;}// also make sure the screen stays on for better user experiencesInstance.mScreenWakeLock = null;if (sInstance.mPowerManager.isScreenOn()) {try {sInstance.mScreenWakeLock = sInstance.mPowerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK, TAG + "-screen");sInstance.mScreenWakeLock.setReferenceCounted(false);sInstance.mScreenWakeLock.acquire();} catch (SecurityException e) {Log.w(TAG, "No permission to acquire wake lock", e);sInstance.mScreenWakeLock = null;}}if (SecurityLog.isLoggingEnabled()) {SecurityLog.writeEvent(SecurityLog.TAG_OS_SHUTDOWN);}// start the thread that initiates shutdownsInstance.mHandler = new Handler() {};sInstance.start();
}

首先初始化一个关机页面showShutdownDialog，弹出页面，然后sInstance.start();执行真正的关机操作

/*** Makes sure we handle the shutdown gracefully.* Shuts off power regardless of radio state if the allotted time has passed.*/
public void run() {TimingsTraceLog shutdownTimingLog = newTimingsLog();shutdownTimingLog.traceBegin("SystemServerShutdown");metricShutdownStart();metricStarted(METRIC_SYSTEM_SERVER);// Start dumping check points for this shutdown in a separate thread.Thread dumpCheckPointsThread = ShutdownCheckPoints.newDumpThread(new File(CHECK_POINTS_FILE_BASENAME));dumpCheckPointsThread.start();BroadcastReceiver br = new BroadcastReceiver() {@Override public void onReceive(Context context, Intent intent) {// We don't allow apps to cancel this, so ignore the result.actionDone();}};/** Write a system property in case the system_server reboots before we* get to the actual hardware restart. If that happens, we'll retry at* the beginning of the SystemServer startup.*/{String reason = (mReboot ? "1" : "0") + (mReason != null ? mReason : "");SystemProperties.set(SHUTDOWN_ACTION_PROPERTY, reason);}/** If we are rebooting into safe mode, write a system property* indicating so.*/if (mRebootSafeMode) {SystemProperties.set(REBOOT_SAFEMODE_PROPERTY, "1");}shutdownTimingLog.traceBegin("DumpPreRebootInfo");try {Slog.i(TAG, "Logging pre-reboot information...");PreRebootLogger.log(mContext);} catch (Exception e) {Slog.e(TAG, "Failed to log pre-reboot information", e);}shutdownTimingLog.traceEnd(); // DumpPreRebootInfometricStarted(METRIC_SEND_BROADCAST);shutdownTimingLog.traceBegin("SendShutdownBroadcast");Log.i(TAG, "Sending shutdown broadcast...");// First send the high-level shut down broadcast.mActionDone = false;Intent intent = new Intent(Intent.ACTION_SHUTDOWN);intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND | Intent.FLAG_RECEIVER_REGISTERED_ONLY);mContext.sendOrderedBroadcastAsUser(intent,UserHandle.ALL, null, br, mHandler, 0, null, null);final long endTime = SystemClock.elapsedRealtime() + MAX_BROADCAST_TIME;synchronized (mActionDoneSync) {while (!mActionDone) {long delay = endTime - SystemClock.elapsedRealtime();if (delay <= 0) {Log.w(TAG, "Shutdown broadcast timed out");break;} else if (mRebootHasProgressBar) {int status = (int)((MAX_BROADCAST_TIME - delay) * 1.0 *BROADCAST_STOP_PERCENT / MAX_BROADCAST_TIME);sInstance.setRebootProgress(status, null);}try {mActionDoneSync.wait(Math.min(delay, ACTION_DONE_POLL_WAIT_MS));} catch (InterruptedException e) {}}}if (mRebootHasProgressBar) {sInstance.setRebootProgress(BROADCAST_STOP_PERCENT, null);}shutdownTimingLog.traceEnd(); // SendShutdownBroadcastmetricEnded(METRIC_SEND_BROADCAST);Log.i(TAG, "Shutting down activity manager...");shutdownTimingLog.traceBegin("ShutdownActivityManager");metricStarted(METRIC_AM);final IActivityManager am =IActivityManager.Stub.asInterface(ServiceManager.checkService("activity"));if (am != null) {try {am.shutdown(MAX_BROADCAST_TIME);} catch (RemoteException e) {}}if (mRebootHasProgressBar) {sInstance.setRebootProgress(ACTIVITY_MANAGER_STOP_PERCENT, null);}shutdownTimingLog.traceEnd();// ShutdownActivityManagermetricEnded(METRIC_AM);Log.i(TAG, "Shutting down package manager...");shutdownTimingLog.traceBegin("ShutdownPackageManager");metricStarted(METRIC_PM);final PackageManagerService pm = (PackageManagerService)ServiceManager.getService("package");if (pm != null) {pm.shutdown();}if (mRebootHasProgressBar) {sInstance.setRebootProgress(PACKAGE_MANAGER_STOP_PERCENT, null);}shutdownTimingLog.traceEnd(); // ShutdownPackageManagermetricEnded(METRIC_PM);// Shutdown radios.shutdownTimingLog.traceBegin("ShutdownRadios");metricStarted(METRIC_RADIOS);shutdownRadios(MAX_RADIO_WAIT_TIME);if (mRebootHasProgressBar) {sInstance.setRebootProgress(RADIO_STOP_PERCENT, null);}shutdownTimingLog.traceEnd(); // ShutdownRadiosmetricEnded(METRIC_RADIOS);if (mRebootHasProgressBar) {sInstance.setRebootProgress(MOUNT_SERVICE_STOP_PERCENT, null);// If it's to reboot to install an update and uncrypt hasn't been// done yet, trigger it now.uncrypt();}// Wait for the check points dump thread to finish, or kill it if not finished in time.shutdownTimingLog.traceBegin("ShutdownCheckPointsDumpWait");try {dumpCheckPointsThread.join(MAX_CHECK_POINTS_DUMP_WAIT_TIME);} catch (InterruptedException ex) {}shutdownTimingLog.traceEnd(); // ShutdownCheckPointsDumpWaitshutdownTimingLog.traceEnd(); // SystemServerShutdownmetricEnded(METRIC_SYSTEM_SERVER);saveMetrics(mReboot, mReason);// Remaining work will be done by init, including vold shutdownrebootOrShutdown(mContext, mReboot, mReason);
}

可以看到发出Intent.ACTION_SHUTDOWN广播，并且执行关机操作。

总结：

点击电源键，执行PhoneWindowManager里的dispatchUnhandledKey方法

然后在dispatchUnhandledKey进行处理，当判断是长按事件时，会执行powerLongPress方法

然后在执行showGlobalActionsInternal()弹出(飞行模式，关机，重启等)

在我们点击关机的时候，会执行PowerAction的onPress方法，执行WindowManagerService的shutdown方法，进而执行ShutdownThread的shutdown方法，在里面会执行真正的关机操作，并且可以看到，系统在关机之前会发出一个Intent.ACTION_SHUTDOWN广播后执行关机。

链接：https://blog.csdn.net/jwg1988/article/details/123631476?spm=1001.2014.3001.5501