在系统中,当前电池电量的广播如下:

Intent.Action_Battery_Changed

前两个使用系统广播的例子都是在mainfirst中配置receive。这次我们在程序中注册,同时使用匿名类来实现BroadcastReceiver。

public class Main extends Activity
{
	private TextView tvBatteryChanged;
	private BroadcastReceiver batteryChangedReceiver = new BroadcastReceiver()
	{

		@Override
		public void onReceive(Context context, Intent intent)
		{
			if (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction()))
			{
				int level = intent.getIntExtra("level", 0);
				int scale = intent.getIntExtra("scale", 100);
				tvBatteryChanged.setText("电池用量:" + (level * 100 / scale) + "%");
			}
		}
	};

	@Override
	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		tvBatteryChanged = (TextView) findViewById(R.id.tvBatteryChanged);
		registerReceiver(batteryChangedReceiver, new IntentFilter(
				Intent.ACTION_BATTERY_CHANGED));
	}   
}
其中level表示当前电量的值,scale表示电量的总刻度。