删除项目后如何重新加载/刷新 RecyclerView

Question

I have already tried many solution from this site. But still does not get the working solution.

This is my Fragment class. I have set the Adpater in this class.

public class FeedFragment extends Fragment {
    RecyclerView recyclerView;
    Context context;
    FloatingActionButton addFeedButton;
    private ArrayList<Feed> feeds;
    FeedService feedService;
    FeedRecyclerViewAdapter feedRecyclerViewAdapter;
    TextView noDataTextView;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {


        View view = inflater.inflate(R.layout.fragment_feed, container, false);
        noDataTextView = view.findViewById(R.id.no_data_textView);
        addFeedButton = view.findViewById(R.id.feed_floating_button);
        System.out.println(getRole());
        if (getRole().equals("ROLE_ADMIN")) {
            addFeedButton.setVisibility(View.VISIBLE);
        } else {
            addFeedButton.setVisibility(View.GONE);
        }
        addFeedButton.setOnClickListener(v -> {
            AddFeedFragment addFeedFragment = new AddFeedFragment();
            FragmentManager fragmentManager = Objects.requireNonNull(getActivity()).getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.replace(R.id.container_for_fragments, addFeedFragment);
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();

        });
        recyclerView = view.findViewById(R.id.feedRecyclerView);
        recyclerView.setHasFixedSize(true);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false);
        recyclerView.setLayoutManager(linearLayoutManager);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        initializeData();
        return view;
    }

    public  void initializeData() {
        feedService = APIUtils.getFeedService();
        feedService.getFeeds(AuthenticationToken()).enqueue(new Callback<List<Feed>>() {
            @Override
            public void onResponse(Call<List<Feed>> call, Response<List<Feed>> response) {
                if (response.isSuccessful()) {
                    if (response != null) {
                        feeds = new ArrayList<>(response.body());
                        if(feeds.isEmpty()){
                            noDataTextView.setVisibility(View.VISIBLE);
                        }
                        else {
                            feedRecyclerViewAdapter = new FeedRecyclerViewAdapter(getActivity(), feeds);
                            recyclerView.setAdapter(feedRecyclerViewAdapter);
                        }
                    }

                } else {
                    Toast.makeText(getContext(), "Unauthorized", Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(Call<List<Feed>> call, Throwable t) {
                Toast.makeText(getContext(), t.getMessage(), Toast.LENGTH_LONG).show();
            }
        });
    }

    private String AuthenticationToken() {
        PrefManager prefManager = new PrefManager(getContext());
        return prefManager.Authorization();
    }

    private String getRole() {
        PrefManager prefManager = new PrefManager(getContext());
        return prefManager.getRole();
    }


}

And this is my Adapter class.

public class FeedRecyclerViewAdapter extends RecyclerView.Adapter<FeedRecyclerViewAdapter.FeedViewHolder> {
    private ArrayList<Feed> feeds;
    private Context context;
    FeedService feedService;
    ProfileService profileService;

    public FeedRecyclerViewAdapter(Context context, ArrayList<Feed> feeds) {
        this.feeds = feeds;
        this.context = context;
    }


    public static class FeedViewHolder extends RecyclerView.ViewHolder {
        CardView feedCardView;
        TextView textViewTitle, textViewDescription, textViewPostBy, textViewPostDate, textViewMobile;
        TextView textViewOption;
        ImageView imageView,callButtonView;

        public FeedViewHolder(@NonNull @NotNull View itemView) {
            super(itemView);
            feedCardView = itemView.findViewById(R.id.feedCardView);
            imageView=itemView.findViewById(R.id.user_photo);
            callButtonView=itemView.findViewById(R.id.callButton);
            textViewTitle = itemView.findViewById(R.id.feedTitle);
            textViewDescription = itemView.findViewById(R.id.feedDescription);
            textViewPostBy = itemView.findViewById(R.id.postBy);
            textViewPostDate = itemView.findViewById(R.id.posDate);
            textViewMobile = itemView.findViewById(R.id.mobile);
            textViewOption = itemView.findViewById(R.id.three_dot);
        }
    }

    @NonNull
    @NotNull
    @Override
    public FeedRecyclerViewAdapter.FeedViewHolder onCreateViewHolder(@NonNull @NotNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.feed_custom_layout, parent, false);
        FeedViewHolder fvh = new FeedViewHolder(view);
        return fvh;
    }

    @Override
    public void onBindViewHolder(@NonNull @NotNull FeedViewHolder holder, int position) {
        final long itemId = feeds.get(position).getId();
        final String profilePicName=feeds.get(position).getUser().getProfile().getProfilePic();
        profileService= APIUtils.getProfileService();
        profileService.loadProfile(AuthenticationToken(),profilePicName).enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                System.out.println(response.code());
                if(response.isSuccessful()){
                    try {
                        byte[] bytes=response.body().bytes();
                        Bitmap bitmap= BitmapFactory.decodeByteArray(bytes,0,bytes.length);
                        Glide.with(context).asBitmap()
                                .load(bitmap)
                                .apply(RequestOptions.diskCacheStrategyOf(DiskCacheStrategy.ALL))
                                .placeholder(R.drawable.account_circle).into(holder.imageView);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }


                }
                else{
                    Toast.makeText(context,"Load failed",Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {
                Toast.makeText(context,t.getMessage(),Toast.LENGTH_LONG).show();

            }
        });
        holder.textViewTitle.setText(feeds.get(position).getFeedTitle());
        holder.textViewDescription.setText(feeds.get(position).getFeedDescription());
        holder.textViewPostBy.setText(feeds.get(position).getUser().getFullName());
        holder.textViewPostDate.setText(feeds.get(position).getPostDate());
        holder.textViewMobile.setText(feeds.get(position).getUser().getMobile());
        holder.callButtonView.setOnClickListener(v -> {
            String phone=feeds.get(position).getUser().getMobile();
            String dialCall="tel:"+phone;
            Intent intent=new Intent(Intent.ACTION_CALL);
            intent.setData(Uri.parse(dialCall));
            context.startActivity(intent);
        });

        ItemAnimation.animateFadeIn(holder.itemView, position);
        if(getRole().equals("ROLE_ADMIN")){
            holder.textViewOption.setOnClickListener(v -> {
                PopupMenu popupMenu = new PopupMenu(context, holder.textViewOption);
                popupMenu.inflate(R.menu.update_delete_menu);
                popupMenu.setOnMenuItemClickListener(item -> {
                    switch (item.getItemId()) {
                        case R.id.popup_update:
                            AlertDialog.Builder builder= new AlertDialog.Builder(v.getContext());
                            builder.setTitle(R.string.dialog_feed_update_title);
                            builder.setPositiveButton(R.string.dialog_yes, (dialog, which) -> {
                                Intent intent = new Intent(context, FeedUpdateActivity.class);
                                intent.putExtra("feedId", itemId);
                                context.startActivity(intent);

                            });
                            builder.setNegativeButton(R.string.dialog_no, (dialog, which) -> {
                                Toast.makeText(context.getApplicationContext(),"Canceled",Toast.LENGTH_LONG).show();
                            });
                            builder.create().show();
                            break;
                        case R.id.popup_delete:
                            AlertDialog.Builder builder1 = new AlertDialog.Builder(v.getContext());
                            builder1.setTitle(R.string.dialog_delete_title);
                            builder1.setPositiveButton(R.string.dialog_yes, (dialog, which) -> {
                                feedService = APIUtils.getFeedService();
                                feedService.deleteFeed(itemId, AuthenticationToken()).enqueue(new Callback<ResponseBody>() {
                                    @Override
                                    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                                        if (response.isSuccessful()) {
                                            Toast.makeText(context.getApplicationContext(), "Deleted", Toast.LENGTH_LONG).show();
                                            notifyDataSetChanged();
                                        } else {
                                            Toast.makeText(context.getApplicationContext(), "Delete Failed", Toast.LENGTH_LONG).show();
                                        }

                                    }

                                    @Override
                                    public void onFailure(Call<ResponseBody> call, Throwable t) {
                                        Toast.makeText(context.getApplicationContext(), t.getMessage(), Toast.LENGTH_LONG).show();
                                    }
                                });

                            });
                            builder1.setNegativeButton(R.string.dialog_no, (dialog, which) -> {
                                Toast.makeText(context.getApplicationContext(), "Canceled", Toast.LENGTH_LONG).show();
                            });
                            builder1.create().show();
                            break;
                    }
                    return false;
                });
                popupMenu.show();
            });
        }
        else{
            holder.textViewOption.setVisibility(View.GONE);
        }

    }

    @Override
    public void onAttachedToRecyclerView(@NotNull RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
    }

    @Override
    public int getItemCount() {
        return feeds.size();
    }

    private String AuthenticationToken() {
        PrefManager prefManager = new PrefManager(context.getApplicationContext());
        return prefManager.Authorization();
    }

    private String getRole() {
        PrefManager prefManager = new PrefManager(context.getApplicationContext());
        return prefManager.getRole();
    }
    }

Here I have called the notifyDataSetChange . But it can not refresh the arraylist set in the Fragment class. How can I refresh that arraylist in fragment after the deletion is completed in Adapter class.

Answer 1

You can use DiffUtil to load data into the recyclerview adapter. For the on click listener you can implement that method in the fragment itself(create interface in the adapter class, implement method in fragment, and pass instance of the interface to the adapter's constructor). Now you can manipulate the data as much as you want by changing the original list.