删除项目后如何重新加载/刷新 RecyclerView

Question

我已经尝试了该站点的许多解决方案。 但仍然没有得到有效的解决方案。

这是我的片段 class。 我已经在这个 class 中设置了 Adpater。

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();
    }


}

这是我的适配器 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();
    }
    }

在这里，我调用了notifyDataSetChange 。 但无法刷新Fragment arraylist中设置的arraylist。 在适配器 class 中完成删除后，如何刷新片段中的arraylist 。

Answer 1

您可以使用 DiffUtil 将数据加载到 recyclerview 适配器中。 对于点击监听器，您可以在片段本身中实现该方法（在适配器 class 中创建接口，在片段中实现方法，并将接口的实例传递给适配器的构造函数）。 现在，您可以通过更改原始列表来尽可能多地操作数据。