回收站视图仅在我从房间数据库中删除后重新打开活动时更新

Question

我有一个带有 Recycler 视图的片段，它显示了房间数据库中的内容。在我的适配器中，我有一个 ImageButton，单击该按钮会从列表中删除该项目。我可以确认该项目已从数据库中删除，但我的列表没有预期的行为。为了更新它，我必须再次打开活动。

回收站视图

public class WishlistFragment extends Fragment {
        private static WishlistAdapter mAdapter;
        private RecyclerView mRecyclerView;
        protected static List<String> wishlist;
        private Context context;
        protected static OnRestaurantClickedListener listener;
        private FirebaseAuth mAuth;

        public static WishlistAdapter getmAdapter() {
            return mAdapter;
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            context = getContext();
            mAuth = FirebaseAuth.getInstance();
            wishlist = new ArrayList<>();
            mAdapter = new WishlistAdapter(context, wishlist,getActivity(),mAuth.getCurrentUser().getUid());
            LoadWishlistTask lwt=new LoadWishlistTask(getActivity(),wishlist,mAdapter,mAuth.getCurrentUser().getUid());
            lwt.execute();

        }


        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            View mContentView = inflater.inflate(R.layout.restaurants_list, container, false);
            mRecyclerView = mContentView.findViewById(R.id.recycler_view);
            mRecyclerView.setLayoutManager(new LinearLayoutManager(mContentView.getContext()));
            mRecyclerView.setAdapter(mAdapter);
            RecyclerView.ItemDecoration itemDecoration = new DividerItemDecoration(context, DividerItemDecoration.VERTICAL);
            mRecyclerView.addItemDecoration(itemDecoration);

            return mContentView;
        }

        @Override
        public void onResume() {
            super.onResume();
        }

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            try {
                listener = (OnRestaurantClickedListener) activity;
            } catch (ClassCastException e) {
                throw new ClassCastException(activity.toString() + " must implement OnRestaurantClickedClicked");
            }
        }
}

适配器

public class WishlistAdapter extends RecyclerView.Adapter<WishlistAdapter.WishlistViewHolder> {
    private Context mContext;
    private List<String> mRestaurantIds;
    private Activity act;
    private String currentUserId;

    public WishlistAdapter(Context context, List<String> ids,Activity activity,String currentUser) {
        mRestaurantIds=ids;
        mContext = context;
        act=activity;
        currentUserId=currentUser;

    }

    @Override
    public WishlistViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // Get layout inflater from context
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);

        // Inflate layout
        View rView = inflater.inflate(R.layout.item_restaurant, parent, false);

        // Return a new holder instance
        return new WishlistViewHolder(rView);
    }

    @Override
    public void onBindViewHolder(final WishlistViewHolder viewHolder, final int position) {
        // Get the data model based on position
        final String id = mRestaurantIds.get(position);

        getApi().getRestaurantDetails(Integer.parseInt(id), "75be9f9e2239fe637bf9cb1b46979d91")
                .enqueue(new Callback<Restaurant_>() {
                    @Override
                    public void onResponse(Call<Restaurant_> call, Response<Restaurant_> response) {
                        final TextView name=viewHolder.nameTextView;
                        name.setText(response.body().getName());
                        final TextView rating=viewHolder.ratingTextView;
                        rating.setText(response.body().getUserRating().getAggregateRating());
                        final ImageButton remove=viewHolder.removeButton;
                        remove.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                Wishlist deletedRestaurant=new Wishlist(currentUserId,id);
                                RemoveWLTask rt=new RemoveWLTask(deletedRestaurant,act,WishlistFragment.wishlist);
                                rt.execute();
                            }
                        });

                        viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                WishlistFragment.listener.onRestaurantClicked(id);
                            }
                        });

                    }

                    @Override
                    public void onFailure(Call<Restaurant_> call, Throwable t) {
                        AlertDialog.Builder builder = new AlertDialog.Builder(act);
                        builder.setMessage("Couldn´t load restaurant details");
                        AlertDialog mDialog = builder.create();
                        mDialog.show();
                    }
                });

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

    private Retrofit getRetrofit() {
        return new Retrofit.Builder()
                .baseUrl("https://developers.zomato.com/api/v2.1/")
                .addConverterFactory(GsonConverterFactory.create())
                .build();
    }

    private ZomatoApi getApi() {
        return getRetrofit().create(ZomatoApi.class);
    }


    public class WishlistViewHolder extends RecyclerView.ViewHolder {
        public TextView nameTextView;
        public TextView ratingTextView;
        public TextView distanceTextView;
        public ImageButton removeButton;

        public WishlistViewHolder(View itemView) {
            super(itemView);
            nameTextView = itemView.findViewById(R.id.restaurantName);
            ratingTextView=itemView.findViewById(R.id.restaurantRating);
            distanceTextView=itemView.findViewById(R.id.restaurantDistance);
            removeButton=itemView.findViewById(R.id.wishlistButton);


        }

    }

}

删除任务

public class RemoveWLTask extends AsyncTask<Void,Void,Void> {
    private Wishlist deletedRestaurant;
    private DB db;
    private Activity activity;
    private List<String> wishlist;

    public  RemoveWLTask (Wishlist deletedRestaurant, Activity activity,List<String> wishlist) {
        this.deletedRestaurant=deletedRestaurant;
        this.activity=activity;
        this.db= Room.databaseBuilder(activity.getApplicationContext(), DB.class, "sample-db").build();
        this.wishlist=wishlist;

    }

    @Override
    protected Void doInBackground(Void... voids) {
        while (!isCancelled()){
            db.daoAcess().deleteFromWishlist(deletedRestaurant);
            break;
        }
        return null;
    }

    @Override
    protected void onPostExecute (Void aVoid) {

        int index = wishlist.indexOf(deletedRestaurant);
        wishlist.remove(deletedRestaurant);
        WishlistFragment.getmAdapter().notifyItemRemoved(index);
        WishlistFragment.getmAdapter().notifyItemRangeChanged(index, wishlist.size());

    }
}

Answer 1

发现错误，我需要将 deletedRestaurant.getRestaurantId() 作为参数而不是 deletedRestaurant 传递