我无法使用removeObserver停止片段内实时数据的观察者

Question

我有一个片段，它是活动中的一个选项卡（以及其他几个选项卡）。在片段的一部分中，我想要

observe

我的

Livedata

的

fjViewModel

一次。这是代码：

public class JInPersonFragment extends Fragment {


    private FJViewModel fjViewModel;

    public static JInPersonFragment newInstance() {return new JInPersonFragment();}

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        _InPerson = FragmentJInPersonBinding.inflate(getLayoutInflater());
        fjViewModel = new ViewModelProvider(requireActivity()).get( FJViewModel.class);


        Observer<Filterj> observer = new Observer<Filterj>() {
            @Override
            public void onChanged(Filterj filterj)
            {//the code keeps coming back inside the onChanged() method
                Log.i("jinperson",""+(filterj==null)); 

                 ....

                fjViewModel.getFiltersById(0).removeObserver(this);
            }
        };

        fjViewModel.getFiltersById(0).observe(getViewLifecycleOwner(), observer);

       return _InPerson.getRoot();
    }

上面的代码显然没有删除观察者。我究竟做错了什么？我现在只懂 Java，无法理解 Kotlin 中的答案。

Answer 1

尝试调用 fjViewModel.getFiltersById(0).removeObservers(getViewLifecycleOwner());

public class JInPersonFragment extends Fragment {


private FJViewModel fjViewModel;

public static JInPersonFragment newInstance() {return new JInPersonFragment();}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    _InPerson = FragmentJInPersonBinding.inflate(getLayoutInflater());
    fjViewModel = new ViewModelProvider(requireActivity()).get( FJViewModel.class);


    Observer<Filterj> observer = new Observer<Filterj>() {
        @Override
        public void onChanged(Filterj filterj)
        {//the code keeps coming back inside the onChanged() method
            Log.i("jinperson",""+(filterj==null)); 

             ....

            fjViewModel.getFiltersById(0).removeObservers(getViewLifecycleOwner());
        }
    };

    fjViewModel.getFiltersById(0).observe(getViewLifecycleOwner(), observer);

   return _InPerson.getRoot();
}