如何更改 Recyclerview 所选项目的背景

Question

我很想改变Recyclerview所选项目的背景（只有一个）：

爪哇：

public class HorizontalViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        ImageView img;

        private SparseBooleanArray selectedItem = new SparseBooleanArray();

        public HorizontalViewHolder(View itemView) {

            super(itemView);

            img = (ImageView) itemView.findViewById(R.id.img);

            itemView.setOnClickListener(this);

        }

        void onBindView(int position) {

            final String s = spacecrafts.get(position);

            Glide.with(c).asBitmap().load(s).apply(new RequestOptions().diskCacheStrategy(DiskCacheStrategy.ALL))

                    .listener(new RequestListener<Bitmap>() {

                        @Override

                        public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Bitmap> target, boolean isFirstResource) {

                            return false;

                        }

                        @Override

                        public boolean onResourceReady(Bitmap resource, Object model, Target<Bitmap> target, DataSource dataSource, boolean isFirstResource) {

                            return false;

                        }

                    }).into(img);

        }

        @Override

        public void onClick(View view) {

            monRecyclerViewClickListener.onClick(view, spacecrafts.get(getAdapterPosition()));

            if (selectedItem.get(getAdapterPosition(), false)) {

                selectedItem.clear();

                view.setSelected(false);

            } else {

                selectedItem.put(getAdapterPosition(), true);

                view.setSelected(true);

            }

            // img.setBackgroundDrawable(c.getResources().getDrawable(R.drawable.imagebordertwo));

        }

    }

问题： 当我选择另一个项目时，前一个项目保持选中状态

Answer 1

尝试这个private int selectedIndex = -1;@Overridepublic void onBindViewHolder(ViewHolder holder, int position) {&nbsp; &nbsp; holder.btn1.setOnClickListener( v -> {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (selectedIndex != position) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; selectedIndex = position;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; notifyDataSetChanged();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; );&nbsp; &nbsp; // Change here the background of unselected item&nbsp; &nbsp; if (selectedIndex == position) {&nbsp; &nbsp; &nbsp; &nbsp; // Change here the background of selected item&nbsp; &nbsp; }}