android recyclerview分组怎么实现

要实现Android RecyclerView的分组功能，可以按照以下步骤进行：

1. 创建一个包含分组数据和子项数据的数据结构。可以使用一个包含分组名称和子项列表的对象来表示每个分组。例如：

public class GroupData {
private String groupName;
private List<ItemData> itemList;
// getter and setter methods
}
public class ItemData {
private String itemName;
// getter and setter methods
}

2. 创建一个RecyclerView的Adapter类，继承自RecyclerView.Adapter。在Adapter类中，需要创建两个ViewHolder类，一个用于显示分组，另一个用于显示子项。例如：

public class GroupViewHolder extends RecyclerView.ViewHolder {
private TextView groupNameTextView;
public GroupViewHolder(View itemView) {
super(itemView);
groupNameTextView = itemView.findViewById(R.id.group_name_textview);
}
public void bind(GroupData groupData) {
groupNameTextView.setText(groupData.getGroupName());
}
}
public class ItemViewHolder extends RecyclerView.ViewHolder {
private TextView itemNameTextView;
public ItemViewHolder(View itemView) {
super(itemView);
itemNameTextView = itemView.findViewById(R.id.item_name_textview);
}
public void bind(ItemData itemData) {
itemNameTextView.setText(itemData.getItemName());
}
}
public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<GroupData> groupList;
// constructor and other methods
@Override
public int getItemCount() {
return groupList.size();
}
@Override
public int getItemViewType(int position) {
if (position < 0 || position >= groupList.size()) {
return -1;
}
return groupList.get(position).getItemList().isEmpty() ? 0 : 1;
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
if (viewType == 0) {
View view = layoutInflater.inflate(R.layout.group_layout, parent, false);
return new GroupViewHolder(view);
} else {
View view = layoutInflater.inflate(R.layout.item_layout, parent, false);
return new ItemViewHolder(view);
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
if (holder instanceof GroupViewHolder) {
((GroupViewHolder) holder).bind(groupList.get(position));
} else if (holder instanceof ItemViewHolder) {
((ItemViewHolder) holder).bind(groupList.get(position).getItemList().get(0));
}
}
}

3. 在Activity或Fragment中，创建RecyclerView并设置Adapter。例如：

RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
MyAdapter myAdapter = new MyAdapter(groupList);
recyclerView.setAdapter(myAdapter);

这样就可以实现RecyclerView的分组功能了。