在onCreateViewHolder中获取View的位置-Java 学习之路

我正在使用带有ImageView和TextView的单行布局的RecyclerView .

我想为View实现一个OnClickListener，而不是为单独的ViewHolder对象实现 . 如何在适配器中获取视图的位置？

现在我正在删除点击的评论，但我无法选择点击的视图 . 我在适当的行中添加了一个TODO .

public class CommentAdapter extends RecyclerView.Adapter<CommentAdapter.ViewHolder> {

    /** List of Comment objects */
    private List<Comment> mCommentList;

    /** Database with Comment objects */
    private CommentsDataSource mDataSource;

    /**
     * Construcutor for CommentAdapter
     *
     * @param commentList   List of Comment objects
     * @param dataSource    Database with Comment objects
     */
    public CommentAdapter(List<Comment> commentList, CommentsDataSource dataSource) {
        this.mCommentList = commentList;
        this.mDataSource = dataSource;
    }

    /**
     * Add Comment objects to RecyclerView
     *
     * @param position  The position where the Comment object is added
     * @param comment   Comment Object
     */
    public void add(int position, Comment comment) {
        mCommentList.add(position, comment);
        notifyItemInserted(position);
    }

    /**
     * Remove Comment objects from RecyclerView
     *
     * @param comment Comment Object
     */
    public void remove(Comment comment) {
        int position = mCommentList.indexOf(comment);
        // Avoid double tap remove
        if (position != -1) {
            mCommentList.remove(position);
            mDataSource.deleteComment(comment);
            notifyItemRemoved(position);
        }
    }

    @Override
    public ViewHolder onCreateViewHolder(final ViewGroup parent, int viewType) {
        final View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.single_line_row, parent, false);
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO get position
                remove(mCommentList.get(getItemCount() - 1));
            }
        });
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        final Comment comment = mCommentList.get(position);
        holder.comment.setText(comment.getComment());
    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {

        /** ImageView icon */
        public ImageView icon;

        /** TextView comment */
        public TextView comment;

        /**
         * Constructor for ViewHolder
         *
         * @param itemView Layout for each row of RecyclerView
         */
        public ViewHolder(final View itemView) {
            super(itemView);
            icon = (ImageView) itemView.findViewById(R.id.icon);
            comment = (TextView) itemView.findViewById(R.id.comment);
        }
    }
}

3 回答

-1

您 cannot 在回调中使用 onBindViewHolder 的 position 参数 . 如果上面添加了新项目，则RecyclerView will not 重新绑定您的项目，以便位置为 obsolete . 相反，RecyclerView在ViewHolder上提供了 getAdapterPosition 方法 .

@Override
public ViewHolder onCreateViewHolder(final ViewGroup parent, int viewType) {
    final View view = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.single_line_row, parent, false);
    final ViewHolder holder = new ViewHolder(view);
    view.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            final int position = holder.getAdapterPosition();
            if (position != RecyclerView.NO_POSITION) {
                remove(mCommentList.get(position));
            }
        }
    });
    return holder;
}

我添加了 position != RecyclerView.NO_POSITION 检查，因为当项目被删除时，RecyclerView会淡出视图，因此用户仍然可以点击它，但其适配器位置将返回 NO_POSITION .

回复于 2024-05-05T23:56:01+08:00

您可以创建一种方法来更新 class 中的位置 .

在我的情况下，我需要附加 watcher 并获得更新 arraylist 的位置 . 这是一个例子：

class DodolWatcher bla bla {
    private var position: Int = 0
    fun updatePosition(pos:Int)
    {
      position = pos
    }

    override fun onTextChanged(charSequence: CharSequence, i: Int, i2: Int, i3: Int) {
    Log.d("test", position.toString())
    }

}

并在您的 onCreateViewHolder 中，您可以将观察者附加到 edittext

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RVPaymentMethodAdapter.ViewHolder {
     ....
     bla bla
     ....
     theWatcher = DodolWatcher() <-- this is the trick
     amount.addTextChangedListener(theWatcher)
 }

你可以像这样更新 bindViewHolder 中的位置：

override fun onBindViewHolder(viewHolder: RVPaymentMethodAdapter.ViewHolder, position: Int) {
     theWatcher.updatePosition(viewHolder.adapterPosition)  <-- this is the trick
 }

回复于 2024-05-05T23:56:01+08:00

覆盖适配器中的getItemViewType方法：

@Override
public int getItemViewType(int position) {
    //...
    return position;
}

现在viewType是位置

@Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
       int position=viewType; //position 
        //your code 

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recursive, parent, false);
        return new ViewHolder(view);
    }

例如

public class BrandBtnAdapter extends RecyclerView.Adapter<BrandBtnAdapter.MyViewHolder>
{

     //............

    @Override
    public int getItemViewType(int position)
    {
        //...
        return position;
    }

    @Override
    public BrandBtnAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        int position = viewType; //position 

        final View itemView = mInflater.inflate(mResource, parent, false);
        return new BrandBtnAdapter.MyViewHolder(itemView);
    }

}

回复于 2024-05-05T23:56:01+08:00

在onCreateViewHolder中获取View的位置

3 回答

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