Question

    @Override
    public void onBindViewHolder(final BookViewHolder holder, final int position) {
        final Upload uploadCurrent = mUploads.get(position);
        holder.iBookName.setText(uploadCurrent.getBookName());
        holder.iBookAuthor.setText(uploadCurrent.getBookAuthor());
        holder.iBookPublisher.setText(uploadCurrent.getBookPublisher());
        /*holder.iBookDesc.setText(uploadCurrent.getBookDesc());*/
        Picasso.with(mContext)
                .load(uploadCurrent.getBookImage())
                .placeholder(R.drawable.blank)
                .fit()
                .into(holder.iBookImage);
        holder.iBookMenu.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                PopupMenu popup = new PopupMenu(mContext, holder.iBookMenu);
                popup.inflate(R.menu.cardview_menu);
                popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    @Override
                    public boolean onMenuItemClick(MenuItem item) {
                        switch (item.getItemId()) {
                            case R.id.add_my_list:
                                break;
                            case R.id.delete_my_list:
                                deleteBook(mUploads.get(position).getBookId());
                                break;
                        }
                        return false;
                    }
                });
                popup.show();
            }
        });
    }

    private void deleteBook(String id) {
        DatabaseReference dR = FirebaseDatabase.getInstance().getReference("Books").child(id);
        dR.removeValue();
        Toast.makeText(mContext, "Book deleted", Toast.LENGTH_SHORT).show();
    }

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

我创建了一个图书应用。我在弹出菜单中设计了cardview，您可以删除项目。我可以删除项目，但看起来仍然不错。我的问题是删除项目时recyclerview无法刷新。你能帮助我吗？我在这里尝试了很多方法，但无法解决问题。

Answer 1

您必须在删除项目刷新适配器之后

 @Override
    public void onBindViewHolder(final BookViewHolder holder, final int position) {
        final Upload uploadCurrent = mUploads.get(position);
        holder.iBookName.setText(uploadCurrent.getBookName());
        holder.iBookAuthor.setText(uploadCurrent.getBookAuthor());
        holder.iBookPublisher.setText(uploadCurrent.getBookPublisher());
        /*holder.iBookDesc.setText(uploadCurrent.getBookDesc());*/
        Picasso.with(mContext)
                .load(uploadCurrent.getBookImage())
                .placeholder(R.drawable.blank)
                .fit()
                .into(holder.iBookImage);
        holder.iBookMenu.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                PopupMenu popup = new PopupMenu(mContext, holder.iBookMenu);
                popup.inflate(R.menu.cardview_menu);
                popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    @Override
                    public boolean onMenuItemClick(MenuItem item) {
                        switch (item.getItemId()) {
                            case R.id.add_my_list:
                                break;
                            case R.id.delete_my_list:
                                deleteBook(mUploads.get(position).getBookId(),position);
                                break;
                        }
                        return false;
                    }
                });
                popup.show();
            }
        });
    }

private void deleteBook(String id,int position) {
        DatabaseReference dR = FirebaseDatabase.getInstance().getReference("Books").child(id);
        dR.removeValue();
        // position of item delete in your adapter model
        notifyItemRemoved(position);
        Toast.makeText(mContext, "Book deleted", Toast.LENGTH_SHORT).show();
    }

Answer 2

您应该使用

@Override
public void onClick(View v) {
notifyDataSetChanged() 
}

在项目删除方法中。

Answer 3

在对同一问题感到无奈之后，我将// function to prepend 0 to a minute if the minute is under 10 Calendar.prototype.displayMinute = function (minute) { minute = (minute < 10) ? '0' + minute : minute; return minute; }; template: "<input type=\"text\" (keyup)='updateMinuteInput($event)' [value]=\"displayMinute(currentMinute)\" >\n",修改为使用RecyclerViewAdapter。

这是我的ListAdapter的样子：

RecyclerViewAdapter

现在，在您的活动中，您可以通过执行以下操作来初始化public class RecyclerViewAdapter extends ListAdapter<YourObjectType, RecyclerViewAdapter.ViewHolder> { ... public RecyclerViewAdapter() { super(DIFF_CALLBACK); ... } public static final DiffUtil.ItemCallback<YourObjectType> DIFF_CALLBACK = new DiffUtil.ItemCallback<YourObjectType>() { @Override public boolean areItemsTheSame(@NonNull YourObjectType oldItem, @NonNull YourObjectType newItem) { return oldItem.compareTo(newItem)==0; //I added a compareTo method to myObjectClass so that I can compare them. } @Override public boolean areContentsTheSame(@NonNull YourObjectType oldItem, @NonNull YourObjectType newItem) { return oldItem.compareTo(newItem)==0; //I added a compareTo method to myObjectClass so that I can compare them. } }; @NonNull @Override public RecyclerViewAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_listitem, parent, false); return new ViewHolder(view); } @Override public void onBindViewHolder(@NonNull final RecyclerViewAdapter.ViewHolder holder, final int position) { ... } class ViewHolder extends RecyclerView.ViewHolder{ ... ViewHolder(View itemView) { super(itemView); ... } } }：

RecyclerView

在列表更新时随时呼叫private void initRecyclerView(){ RecyclerView recyclerView = findViewById(R.id.recycler_view); recyclerView.invalidate(); adapter = new RecyclerViewAdapter(); recyclerView.setAdapter(adapter); recyclerView.setLayoutManager(new LinearLayoutManager(this)); }。

就我而言，我在adapter.submitList(yourList);回调中调用了submitList。

我跟随this YouTube tutorial实现了这一目标。

删除项目时刷新RecyclerView

3 个答案: