RecyclerView 视图绑定闪烁且不始终呈现 Android MVVM

Question

I'm using view binding w/ MVVM pattern in my Android app. From the home activity, the user can click on an item which will open a fragment with items displayed in a recycler view. The first time the fragment is rendered the recycler view flickers on and then disappears all together. If I go back to the home activity and select the same item, the recycler view displays as expected without any issues.

This is my call for the recycler view data:

private void getData() {
    titlesViewModel.titlesListLiveData.observe(getViewLifecycleOwner(), titles -> {
        titlesList.clear();

        for (Titles title : titles) {
            titlesList.add(title);
        }

        binding.rvTitles.setAdapter(TitlesAdapter);
        TitlesAdapter.setTitlesList(titlesList);
    });
    titlesViewModel.getAllTitles(Tag);
}

This is my recycler view adapter:

public class TitlesAdapter extends RecyclerView.Adapter<TitlesAdapter.TitlesViewHolder> {
    private ItemTitleBinding binding;
    private ArrayList<Titles> titles;
    private Context context;

    public ShowTitlesAdapter(Context context, ArrayList<Titles> titles){
        this.context = context;
        this.titles = titles;
    }

    @NonNull
    @Override
    public TitlesViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(context);
        binding = ItemTitleBinding.inflate(inflater, parent, false);
        return new TitlesViewHolder(binding);
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    public void onBindViewHolder(@NonNull TitlesViewHolder holder, int position) {
        holder.binding.titleNo.setText(Integer.toString(titles.get(position).getNumber()));
        holder.binding.titleName.setText(titles.get(position).getName());
    }

    @Override
    public int getItemCount() {
        if(titles != null){
            return titles.size();
        }
        return 0;
    }

    public class TitlesViewHolder extends RecyclerView.ViewHolder {

        private ItemTitleBinding binding;

        public TitlesViewHolder(ItemTitleBinding binding) {
            super(binding.getRoot());
            this.binding = binding;

        }
    }

    public void setTitlesList(ArrayList<Titles> titles){
        this.titles = titles;
        notifyDataSetChanged();
    }
  }

I found this , but they're not having issues with a first time render. Has anyone experienced this issue or know what I'm doing wrong?

Answer 1

You can try this code, where you initialise your adapter.

adapter.setHasStableIds(true)

And use this in adapter. In this method you have to return your ListItem id.

override fun getItemId(position: Int): Long {
    if (profileList.size>0){
        return profileList[position].profileId.toLong()
    }else{
        return super.getItemId(position)
    }
}