首页 > 代码库 > Android KK开机按power键不能灭屏，须过会儿才能灭屏
Android KK开机按power键不能灭屏，须过会儿才能灭屏
这是Google issue，原生Android4.4都有此问题。流程是：AMS发出BOOT_COMPLETED，PowerManager收到BOOT_COMPLETED后check Boot animation是否完成，如果完成，就会将内部的成员mBootCompleted置为true，之后再按power键才会正常休眠。
PowerManagerService.java在systemReady()方法中动态注册BootCompletedReceiver监听ACTION_BOOT_COMPLETED
1 filter = new IntentFilter();2 filter.addAction(Intent.ACTION_BOOT_COMPLETED);3 mContext.registerReceiver(new BootCompletedReceiver(), filter, null, mHandler);
1 private final class BootCompletedReceiver extends BroadcastReceiver { 2 @Override 3 public void onReceive(Context context, Intent intent) { 4 if (DEBUG_SPEW) { 5 Slog.d(TAG, "BootCompletedReceiver."); 6 } 7 // This is our early signal that the system thinks it has finished booting. 8 // However, the boot animation may still be running for a few more seconds 9 // since it is ultimately in charge of when it terminates.10 // Defer transitioning into the boot completed state until the animation exits.11 // We do this so that the screen does not start to dim prematurely before12 // the user has actually had a chance to interact with the device.13 startWatchingForBootAnimationFinished();14 }15 }
startWatchingForBootAnimationFinished()发送广播MSG_CHECK_IF_BOOT_ANIMATION_FINISHED检查是否开机动画完成，
1 @Override2 public void handleMessage(Message msg) {3 switch (msg.what) {4 ……5 case MSG_CHECK_IF_BOOT_ANIMATION_FINISHED:6 checkIfBootAnimationFinished();7 break;8 }9 }
1 private void checkIfBootAnimationFinished() { 2 if (DEBUG) { 3 Slog.d(TAG, "Check if boot animation finished..."); 4 } 5 // 检查是否还在跑 bootanim 6 if (SystemService.isRunning(BOOT_ANIMATION_SERVICE)) { 7 mHandler.sendEmptyMessageDelayed(MSG_CHECK_IF_BOOT_ANIMATION_FINISHED, 8 BOOT_ANIMATION_POLL_INTERVAL); 9 return;10 }11 12 synchronized (mLock) {13 if (!mBootCompleted) {14 Slog.i(TAG, "Boot animation finished.");15 handleBootCompletedLocked();16 }17 }18 }
这里用到SystemService.isRunning(BOOT_ANIMATION_SERVICE)判断系统开机动画是否还在运行，若isRunning继续Check，否则，动画完成handleBootCompletedLocked()；
1 private void handleBootCompletedLocked() { 2 final long now = SystemClock.uptimeMillis(); 3 mBootCompleted = true; 4 mDirty |= DIRTY_BOOT_COMPLETED; 5 userActivityNoUpdateLocked( 6 now, PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID); 7 if ( mWakefulness == WAKEFULNESS_AWAKE ) { 8 mNotifier.onWakeUpStarted(); 9 }10 updatePowerStateLocked();11 }
到这里mBootCompleted系统才正在起来，通知更新State。
至此，还是只找到原因，没有好的处理方法，希望高手指点，科普，交流。
目前，比较拙劣的方法是将mBootCompleted=True，设为TRUE。这个改法是让powermanager不去check boot_completed，这样可能会产生影响：刚刚开机就按power键灭屏后，再次按power键是否能正常resume回来。主要是考虑到AMS此时可能还在发BOOT_COMPLETED，而按power键灭屏和亮屏的流程会需要AMS发SCREEN_OFF、SCREEN_ON的intent，担心ActivityManagerService在BOOT_COMPLETED还没发完的情况下又要响应去发SCREEN_OFF和SCREEN_ON。
Android KK开机按power键不能灭屏，须过会儿才能灭屏