在模型（MVVM）中使用实时数据的问题

Question

我想用MVVM模式实现一个android应用程序。我的应用程序有几个活动和片段。每个活动或片段都有一个自定义操作（向服务器发送请求，向数据库查询，从文件读取等）。我的应用程序具有用于与数据库，网络，文件等进行交互的多个模块。问题是某些操作需要与多个组件联系，然后将其结果汇总并更新在视图中观察到的LiveData。 是否可以编写一个可以在我所有viewModel中使用的通用包装器？（我知道Transformations（switch或switchMap）和MediatorLiveData，但需要在Activity / Fragment中观察它们）

>

活动

public class RegisterPhoneActivity extends 
AppCompatActivity {


  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActivityRegisterPhoneBinding binding =  DataBindingUtil.setContentView(this, R.layout.activity_register_phone);
    viewModel = ViewModelProviders.of(this).get(RegisterMobileViewModel.class);
    binding.setViewModel(viewModel);
    binding.setLifecycleOwner(this);
    viewModel.getResponse().observe(this, new Observer<BaseResponse>() {
        @Override
        public void onChanged(BaseResponse baseResponse) {
          //do something
        }
     });
  }
}

ViewModel

public class RegisterMobileViewModel extends ViewModel {


  public void onRegisterButtonClick() {
    BaseSender.getInstance().sendRequest(new RegisterCommand());
  }


  public LiveData getResponse(){
    BaseSender.getInstance.getResponse();
  }

}

模型（网络模型）

public class BaseSender {


  //observed in Activity  -- this design only works when i have a single network call
  private MutableLiveData<String> response = new MutableLiveData<>();



  private static BaseSender instance;

  private BaseSender() {

  }

  public static BaseSender getInstance() {
    if (instance == null) {
      instance = new BaseSender();
    }
    return instance;
  }


  private class SenderHolder extends AsyncTask<String, Void, String> {


    SenderHolder() {
    }

    @Override
    protected void onPreExecute() {
      super.onPreExecute();
    }

    @Override
    protected String doInBackground(String... strings) {
        // sending request to server
    }

    @Override
    protected void onPostExecute(String s) {
      response.setValue(s);
    }

  }

  public MutableLiveData getResponse() {
    return responseObject;
  }
}