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 before
12             // 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         @Override
2         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系统才真正起来，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。

 

posted on 2014-11-10 20:22  地方v大  阅读(1410)  评论(0)  编辑  收藏  举报

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