batterymonitor//update(void)
Framework
应用层
BatteryReceiver//接受广播
healthd.cpp//battery_update
Kernel
healthd_mode_android.cpp//healthd_mode_android_battery_update
HAL
BatteryListener//监听底层Battery状态变化
batterypropertiesregistrar.cpp//notifyListeners
BatteryProperties//电池变化的属性都分装在这个实体类中
BatteryService.java//batteryPropertiesChanged//发出battery变化的广播
BatteryPropertiesRegistrar//notifyListener
