在Android RecyclerView中添加图标

Question

我有一个recyclerView，它像这样的扩展列表视图：

我想在每个标题的第二个子项（动态生成的子项）中添加一个图标。我在图像中用红色圆圈表示。

这是我的适配器类。

public class ExpandableListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    public static final int HEADER = 0;
    public static final int CHILD = 1;

    private List<Item> data;

    public ExpandableListAdapter(List<Item> data) {
        this.data = data;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int type) {
        View view = null;
        Context context = parent.getContext();
        float dp = context.getResources().getDisplayMetrics().density;
        int subItemPaddingLeft = (int) (18 * dp);
        int subItemPaddingTopAndBottom = (int) (5 * dp);
        switch (type) {
            case HEADER:
                LayoutInflater inflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                view = inflater.inflate(R.layout.list_header, parent, false);
                ListHeaderViewHolder header = new ListHeaderViewHolder(view);
                return header;
            case CHILD:
                TextView itemTextView = new TextView(context);
                itemTextView.setPadding(subItemPaddingLeft, subItemPaddingTopAndBottom, 0, subItemPaddingTopAndBottom);
                itemTextView.setTextColor(0x88000000);
                itemTextView.setLayoutParams(
                        new ViewGroup.LayoutParams(
                                ViewGroup.LayoutParams.MATCH_PARENT,
                                ViewGroup.LayoutParams.WRAP_CONTENT));
                return new RecyclerView.ViewHolder(itemTextView) {
                };
        }
        return null;
    }

    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        final Item item = data.get(position);
        switch (item.type) {
            case HEADER:
                final ListHeaderViewHolder itemController = (ListHeaderViewHolder) holder;
                itemController.refferalItem = item;
                itemController.header_title.setText(item.text);
                if (item.invisibleChildren == null) {
                    itemController.btn_expand_toggle.setImageResource(R.drawable.circle_minus);
                } else {
                    itemController.btn_expand_toggle.setImageResource(R.drawable.circle_plus);
                }
                itemController.btn_expand_toggle.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        if (item.invisibleChildren == null) {
                            item.invisibleChildren = new ArrayList<Item>();
                            int count = 0;
                            int pos = data.indexOf(itemController.refferalItem);
                            while (data.size() > pos + 1 && data.get(pos + 1).type == CHILD) {
                                item.invisibleChildren.add(data.remove(pos + 1));
                                count++;
                            }
                            notifyItemRangeRemoved(pos + 1, count);
                            itemController.btn_expand_toggle.setImageResource(R.drawable.circle_plus);
                        } else {
                            int pos = data.indexOf(itemController.refferalItem);
                            int index = pos + 1;
                            for (Item i : item.invisibleChildren) {
                                data.add(index, i);
                                index++;
                            }
                            notifyItemRangeInserted(pos + 1, index - pos - 1);
                            itemController.btn_expand_toggle.setImageResource(R.drawable.circle_minus);
                            item.invisibleChildren = null;
                        }
                    }
                });
                break;
            case CHILD:
                TextView itemTextView = (TextView) holder.itemView;
                itemTextView.setText(data.get(position).text);
                break;
        }
    }

    @Override
    public int getItemViewType(int position) {
        return data.get(position).type;
    }

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

    private static class ListHeaderViewHolder extends RecyclerView.ViewHolder {
        public TextView header_title;
        public ImageView btn_expand_toggle;
        public Item refferalItem;

        public ListHeaderViewHolder(View itemView) {
            super(itemView);
            header_title = (TextView) itemView.findViewById(R.id.header_title);
            btn_expand_toggle = (ImageView) itemView.findViewById(R.id.btn_expand_toggle);
        }
    }

    public static class Item {
        public int type;
        public String text;
        public List<Item> invisibleChildren;

        public Item() {
        }

        public Item(int type, String text) {
            this.type = type;
            this.text = text;
        }
    }
}

我无法根据自己的要求更改此适配器类。如何更改此适配器类以使可以在每个标头的每个第二个子级中添加图标？

注意：如果需要其他信息，请询问。

Answer 1

如果要继续动态创建TextView，可以使用：

itemTextView.setCompoundDrawablesWithIntrinsicBounds(0, 0, R.drawable.your_drawable, 0);

设置图标。

如果您想更好地控制布局，我建议您使用与标题相似的方法（使用布局膨胀），例如：

LayoutInflater inflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

switch (type) {
    case HEADER:
        view = inflater.inflate(R.layout.list_header, parent, false);
        ListHeaderViewHolder header = new ListHeaderViewHolder(view);
        return header;
    case CHILD:
        view = inflater.inflate(R.layout.list_child, parent, false);
        ListChildViewHolder child = new ListChildViewHolder(view);
        return child;
}

要仅在每个第二个孩子中显示图标，请在您的onBindViewHolder添加：

itemController1.yourIcon.setVisibility((position % 2 == 0) ? View.VISIBLE : View.GONE);