public interface OnUpdateUI {

    void updateUI(String i);

}

public class MyBroadcast extends BroadcastReceiver {

    OnUpdateUI onUpdateUI;

    @Override

    public void onReceive(Context context, Intent intent) {

        String progress = intent.getStringExtra("progress");

        onUpdateUI.updateUI(progress);

    }

    public void SetOnUpdateUI(OnUpdateUI onUpdateUI){

        this.onUpdateUI = onUpdateUI;

    }

}

public class MainActivity extends Activity {

    public static final String FLAG = "UPDATE";

    MyBroadcast myBroadcast;

    TextView tip;

    Intent intent;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        tip = (TextView)findViewById(R.id.tip);

        myBroadcast = new MyBroadcast();

        IntentFilter intentFilter = new IntentFilter();

        intentFilter.addAction(FLAG);

        registerReceiver(myBroadcast, intentFilter);

        intent = new Intent(this, MyService.class);

    // 更新UI

        myBroadcast.SetOnUpdateUI(new OnUpdateUI() {

            @Override

            public void updateUI(String i) {

                tip.setText(i);

            }

        });

    }

    protected void myClick(View v){

    // 发送广播

        if( v.getId() == R.id.btn ){

            Intent intent = new Intent();

            intent.setAction(FLAG);

            intent.putExtra("progress", System.currentTimeMillis()+"");

            sendBroadcast(intent);

        }

    // 启动服务

        if (v.getId() == R.id.btn2){

            startService(intent);

        }

    }

    @Override

    protected void onDestroy() {

        unregisterReceiver(myBroadcast);

        stopService(intent);

        super.onDestroy();

    }

}

Intent it = new Intent();

it.setAction(MainActivity.FLAG);

it.putExtra("progress", i+"");

sendBroadcast(it);