http://blog.csdn.net/u013724061/article/details/38642049

最終效果：

動態顯示當前時間和電量

思路：

首先在Activity裏用內部類定義兩種廣播，一種是系統廣播（電池），另一種是自定義廣播。

private class SimpleBroadcastReceiver extends BroadcastReceiver
    {
        @Override
        public void onReceive(Context context, Intent intent) {
            int currLevel =   intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0
 
);  //當前電量
            int total = intent.getIntExtra(BatteryManager.EXTRA_SCALE,   1);      //總電量
            int percent = currLevel * 100 / total;
            updateG(percent);
            Log.i(TAG, "battery: " + percent + "%");
        }
    }

    private class UpdateTimeReceiver extends BroadcastReceiver
    {
        @Override
        
 
public void onReceive(Context context, Intent intent) {
            Date date = new Date();

            SimpleDateFormat dateFormat = new SimpleDateFormat("MM-dd");
            SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss");

            String dateStr = dateFormat.format(date);
            String timeStr 
 
= timeFormat.format(date);

            tv_date.setText(dateStr + ":" + timeStr);//顯示出日期
        }
    }

在OnResume中註冊廣播，OnPause中移除 （文章中有為什麽不在onStart和onStop中的解釋）

@Override
    protected void onResume() {
        super.onResume();

        IntentFilter intentFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        simpleBroadcastReceiver = new SimpleBroadcastReceiver();
        registerReceiver(simpleBroadcastReceiver, intentFilter);

        intentFilter = new IntentFilter("ACTION_UPDATE_TIME");
        updateTimeReceiver = new UpdateTimeReceiver();
        registerReceiver(updateTimeReceiver, intentFilter);

        Intent intent = new Intent(this,UpdateGService.class);
        startService(intent);
    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(simpleBroadcastReceiver);
        unregisterReceiver(updateTimeReceiver);
        Intent intent = new Intent(this,UpdateGService.class);
        stopService(intent);
    }

建立個service來處理動態更新

public class UpdateGService extends Service {

    @Override
    public void onCreate() {
        super.onCreate();
        new Timer().scheduleAtFixedRate(new TimerTask() {

            @Override
            public void run() {
                Intent timeIntent = new Intent();
                timeIntent.setAction("ACTION_UPDATE_TIME");//自定義Action
                sendBroadcast(timeIntent); //發送廣播
            }
        }, 0, 1000); //每隔1秒
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

最終效果：

Service 動態更新 UI