每次触发BackgroundService时在Mainactivity中获取更新

你可以用 BroadCastReceiver

在你的服务课上

public class Backgroundservice implements AlarmReceiverCallback {
    private Context context;

    public Backgroundservice(Context context) {
        this.context = context;
    }

    @Override
    public void onAlarmReceived() {

       // send broadcast from here
       Intent intent  = new Intent("alaram_received");
       context.sendBroadcast(intent);
    }

在你的主要活动中接收这个广播。

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Register Receiver
        IntentFilter intentFilter = new IntentFilter("alaram_received");
        registerReceiver(alarm_receiver,intentFilter); 
    }

    BroadcastReceiver alarm_receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // refresh Token
        }
    };
}

快乐的编码。

我设法通过创建新的接口使它工作

public interface ReceiverCallback {
public void onReceived();}

在我的主活动中实现,而不是在其中创建新对象

    @Override
public void onReceive(Context context, Intent intent)