在Activity中获取Service对象可以通过以下步骤：

在Activity中使用bindService()方法绑定Service。在onServiceConnected()方法中获取Service对象。

public class MyActivity extends Activity {private MyService myService;private ServiceConnection serviceConnection = new ServiceConnection() {@Overridepublic void onServiceConnected(ComponentName name, IBinder service) {MyService.MyBinder binder = (MyService.MyBinder) service;myService = binder.getService();}@Overridepublic void onServiceDisconnected(ComponentName name) {myService = null;}};@Overrideprotected void onStart() {super.onStart();Intent serviceIntent = new Intent(this, MyService.class);bindService(serviceIntent, serviceConnection, Context.BIND_AUTO_CREATE);}@Overrideprotected void onStop() {super.onStop();unbindService(serviceConnection);}}

在Service中创建一个Binder类用于返回Service对象。

public class MyService extends Service {private final IBinder binder = new MyBinder();public class MyBinder extends Binder {MyService getService() {return MyService.this;}}@Nullable@Overridepublic IBinder onBind(Intent intent) {return binder;}}

通过这样的方式，可以在Activity中获取到Service对象并调用其方法。