Android RecyclerView将偶尔更新

我已经查看了此链接和其他链接：

无法找到解决我遇到的问题的方法。 在某些情况下，RecyclerView会更新其数据，而在其他情况下则不会

在我的代码中，我使用底部导航器，并相应地更新数据。 当我选择MAP，然后选择HISTORY，或者MAP，然后选择底部导航器附近的位置时，数据将更新并正常工作。 如果我选择了历史记录，那么附近的数据将不会更新。 我玩过这个，尝试过几个选项，但都没能让它工作

这是底部导航器中的代码：

bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case (R.id.action_History):
                    showHistory();
                    break;

                case (R.id.action_near):
                    showNear();
                    break;

                case (R.id.action_fav):
                    showFav();
                    break;

                case (R.id.action_map):
                    showMap();
                    break;
                default:
                    break;
            }
            return true;
        }
    });

  private void showMap(){
    constraintMap.setVisibility(View.VISIBLE);

    fragmentManager
            .beginTransaction()
            .replace(container, emptyFragment)
            .commit();

}//showMap

private void showHistory(){
    Bundle bundle = new Bundle();
    bundle.putInt(Util.BOTTOM_NAVIGATOR, Util.HISTORY);
    placeListFragment.setArguments(bundle);

    constraintMap.setVisibility(View.GONE);

    fragmentManager
            .beginTransaction()
            .replace(container, placeListFragment)
            .commit();

}//showHistory

private void showNear(){
    Bundle bundle = new Bundle();
    bundle.putInt(Util.BOTTOM_NAVIGATOR, Util.NEAR);
    placeListFragment.setArguments(bundle);


    constraintMap.setVisibility(View.GONE);

    fragmentManager
            .beginTransaction()
            .replace(container, placeListFragment)
            .commit();

}//showNear

以下是从底部导航器调用的函数：

bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case (R.id.action_History):
                    showHistory();
                    break;

                case (R.id.action_near):
                    showNear();
                    break;

                case (R.id.action_fav):
                    showFav();
                    break;

                case (R.id.action_map):
                    showMap();
                    break;
                default:
                    break;
            }
            return true;
        }
    });

  private void showMap(){
    constraintMap.setVisibility(View.VISIBLE);

    fragmentManager
            .beginTransaction()
            .replace(container, emptyFragment)
            .commit();

}//showMap

private void showHistory(){
    Bundle bundle = new Bundle();
    bundle.putInt(Util.BOTTOM_NAVIGATOR, Util.HISTORY);
    placeListFragment.setArguments(bundle);

    constraintMap.setVisibility(View.GONE);

    fragmentManager
            .beginTransaction()
            .replace(container, placeListFragment)
            .commit();

}//showHistory

private void showNear(){
    Bundle bundle = new Bundle();
    bundle.putInt(Util.BOTTOM_NAVIGATOR, Util.NEAR);
    placeListFragment.setArguments(bundle);


    constraintMap.setVisibility(View.GONE);

    fragmentManager
            .beginTransaction()
            .replace(container, placeListFragment)
            .commit();

}//showNear

这是片段中的onCreateView：

 public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view= inflater.inflate(R.layout.fragment_list_view, container, false);

    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext());

    placesRecyclerView = view.findViewById(R.id.location_recycler_view);
    placesRecyclerView.setLayoutManager(linearLayoutManager);
    placesRecyclerView.setItemAnimator(new DefaultItemAnimator());


    int bottomNavigator;
    if(getArguments() != null){
        bottomNavigator = getArguments().getInt(Util.BOTTOM_NAVIGATOR);

        switch (bottomNavigator){
            case Util.HISTORY:
                placeLocations = dal.getAllPlaceLocationSearchResults();
                break;
            case Util.NEAR:
                placeLocations = dal.getAllPlaceLocationNearResults();
                break;
            case Util.FAVORITE:
                placeLocations = dal.getAllPlaceLocationFavoritesResults();
                break;
            case Util.MAP:
                break;
        }

    } else{
        placeLocations = dal.getAllPlaceLocationSearchResults();
    }

    placeListAdapter = new PlaceListAdapter(placeLocations, listener, mContext);
    placesRecyclerView.setAdapter(placeListAdapter);
    placeListAdapter.refreshListAdapter();


    return view;
}//onCreateView

正如Gal Yedidovich所建议的那样。 我已覆盖onStart。 但这没有帮助

@Override
public void onStart() {
    super.onStart();

    int bottomNavigator;
    if(getArguments() != null){
        bottomNavigator = getArguments().getInt(Util.BOTTOM_NAVIGATOR);

        switch (bottomNavigator){
            case Util.HISTORY:
                placeLocations = dal.getAllPlaceLocationSearchResults();
                break;
            case Util.NEAR:
                placeLocations = dal.getAllNearLocations();
                break;
            case Util.FAVORITE:
                placeLocations = dal.getAllPlaceLocationFavoritesResults();
                break;
            case Util.MAP:
                break;
        }

    } else{
        placeLocations = dal.getAllPlaceLocationSearchResults();
    }

    placeListAdapter = new PlaceListAdapter(placeLocations, listener, mContext);
    placesRecyclerView.setAdapter(placeListAdapter);
    placeListAdapter.refreshListAdapter();


}//onStart

---

无论何时更新recyclerview数据，都应该使用placeListAdapter.refreshListAdapter（），而不是placeListAdapter.notifydatasetchange（）。

我不知道是否要实例化片段一次或多次，但我很确定这是因为片段的生命周期（如果只实例化一次）

覆盖片段中的“onStart”方法 在onStart方法中刷新适配器：

@Override
public void onStart() {
     int bottomNavigator;
     if(getArguments() != null){
        bottomNavigator = getArguments().getInt(Util.BOTTOM_NAVIGATOR);

        switch (bottomNavigator){  
            case Util.HISTORY:
                placeLocations = dal.getAllPlaceLocationSearchResults();
                break;
            case Util.NEAR:
                placeLocations = dal.getAllPlaceLocationNearResults();
                break;
            case Util.FAVORITE:
                placeLocations = dal.getAllPlaceLocationFavoritesResults();
                break;
            case Util.MAP:
                break;
        }

    } else{
        placeLocations = dal.getAllPlaceLocationSearchResults();
    }

    placeListAdapter = new PlaceListAdapter(placeLocations, listener, mContext);
    placesRecyclerView.setAdapter(placeListAdapter); //keep the recycler view as field in fragment calls

    //refresh your adapter
    placeListAdapter.notifyDataSetChanged();
    //or as you already wrote
    placeListAdapter.refreshListAdapter();
}

另一个选项：

请在每次对片段执行事务时尝试实例化它

private void showMap(){
    constraintMap.setVisibility(View.VISIBLE);

    emptyFragment = new EmptyFrag(); //instantiating

    fragmentManager
            .beginTransaction()
            .replace(container, emptyFragment)
            .commit();

}//showMap

private void showHistory(){
    Bundle bundle = new Bundle();
    bundle.putInt(Util.BOTTOM_NAVIGATOR, Util.HISTORY);
    placeListFragment.setArguments(bundle);

    constraintMap.setVisibility(View.GONE);

    placeListFragment = new YourFragment(); //instantiating

    fragmentManager
            .beginTransaction()
            .replace(container, placeListFragment)
            .commit();

}//showHistory

private void showNear(){
    Bundle bundle = new Bundle();
    bundle.putInt(Util.BOTTOM_NAVIGATOR, Util.NEAR);
    placeListFragment.setArguments(bundle);

    placeListFragment = new YourFragment(); //instantiating   

    constraintMap.setVisibility(View.GONE);

    fragmentManager
            .beginTransaction()
            .replace(container, placeListFragment)
            .commit();

}//showNear

---

那么，你也可以发布你的PlaeListAdapter的源代码吗？还有一个问题是，如果每次单击底部导航栏，您是否都在使用

placeListFragment

的单个实例，或者实例化此片段。

adapter.notifydatasetchange（）？我很确定这是因为您不是每次都实例化您的片段，这就是为什么只有当片段被销毁时，才会调用方法“onCreateView”，并刷新适配器。另一种猜测是，问题不在于片段，而在于适配器或DAL。您应该调试它以查看数据是否准确谢谢您的重播。我试过你的建议，没什么区别。也许需要做些额外的事情？谢谢你重播。尝试你的想法，两种选择，结果都是一样的。我想把我的代码粘贴到这里，但不能…太棒了！很高兴这有帮助。