在 android RecyclerView 中添加图标

Question

我有一个 recyclerView，它像这样用作扩展列表视图：

我想每秒添加一个图标 child（Child 个动态生成的项目）每个 header..我在图像中用红色圆圈提到了这一点。

这是我的适配器 class。

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;
        }
    }
}

我无法根据我的要求更改此适配器 class。如何更改此适配器 class 以便可以在每个 child 的每一秒添加图标 header?

注意：如果需要任何其他信息，请询问。

Answer 1

如果您想继续动态创建 TextView，您可以使用：

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

设置图标。

如果您想更好地控制布局，我建议使用与页眉类似的方法（使用布局 inflation），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;
}

要每隔一秒显示一次图标 child，请在您的 onBindViewHolder 中添加：

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

在 android RecyclerView 中添加图标

Adding icon in android RecyclerView

android

expandablelistview

expandablelistadapter

android-arrayadapter

android-recyclerview