读取 android 设备的电池信息

简短说明(Quick explanation):
通过创建BroadcastReceiver来侦测系统中有关电池Intent(ACTION_BATTERY_CHANGED)的变化，一旦有接收到相关事件，将会读取当前电量情况，并通过TextViews显示在当前屏幕。

public class Main extends Activity {       private TextView contentTxt;     private BroadcastReceiver mBatInfoReceiver = newBroadcastReceiver(){            @Override        public void onReceive(Context arg0, Intent intent) {          // TODO Auto-generated method stub          int level = intent.getIntExtra("level", 0);          contentTxt.setText(String.valueOf(level) + "%");        }     };        @Override     public void onCreate(Bundle) {        super.onCreate(icicle);        setContentView(R.layout.main);        contentTxt = (TextView) this.findViewById(R.id.monospaceTxt);        this.registerReceiver(this.mBatInfoReceiver,           new IntentFilter(Intent.ACTION_BATTERY_CHANGED));     }    }