背光之关闭（turnOff）

相关文件：

frameworks/base/services/java/com/android/server/PowerManagerService.java

frameworks/base/services/java/com/android/server/NotificationManagerService.java 

 

 

    private void updateLightsLocked()

对于mBatteryLow是mBatteryLow和mBatteryCharging的时候电池的指示是要显示的，否则关闭。android做成平板机，netbook的时候，一般是有电池指示灯的。

另外：

        // we only flash if screen is off and persistent pulsing is enabled

        // and we are not currently in a call

        if (mLedNotification == null || mScreenOn || mInCall) {

            mNotificationLight.turnOff();

        }

在电源管理的manager代码中，在函数中可见，灯在LCD关闭的时候是要关的。

private int setScreenStateLocked(boolean on) { int err = Power.setScreenState(on); if (err == 0) { mLastScreenOnTime = (on ? SystemClock.elapsedRealtime() : 0); if (mUseSoftwareAutoBrightness) { enableLightSensor(on); if (!on) { // make sure button and key backlights are off too mButtonLight.turnOff(); mKeyboardLight.turnOff(); // clear current value so we will update based on the new conditions // when the sensor is reenabled. mLightSensorValue = -1; // reset our highest light sensor value when the screen turns off mHighestLightSensorValue = -1; } } } return err;  

注意mUseSoftwareAutoBrightness

很多光现象都与之相关，代码查查就好了。SCREEN_BRIGHTNESS也相关的。