/** 
* 
* @author chrp 
* 
*显示当前电池电量 
*/ 
public class MainActivity extends Activity { 
private TextView tv; 
/** 
* 广播接受者 
*/ 
class BatteryReceiver extends BroadcastReceiver{ 
@Override 
public void onReceive(Context context, Intent intent) { 
// TODO Auto-generated method stub 
//判断它是否是为电量变化的Broadcast Action 
if(Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction())){ 
//获取当前电量 
int level = intent.getIntExtra("level", 0); 
//电量的总刻度 
int scale = intent.getIntExtra("scale", 100); 
//把它转成百分比 
tv.setText("电池电量为"+((level*100)/scale)+"%"); 
} 
} 
} 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
//setContentView(R.layout.activity_main); 
tv = new TextView(this); 
tv.setText("chrp"); 
this.setContentView(tv); 
//注册广播接受者java代码 
IntentFilter intentFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED); 
//创建广播接受者对象 
BatteryReceiver batteryReceiver = new BatteryReceiver(); 
//注册receiver 
registerReceiver(batteryReceiver, intentFilter); 
}