android - 根据值(value)对 recyclerview 中的项目进行分组

Question

我有一些带有日期字段的 POJO，我在 RecyclerView 中显示这些字段。现在我只想在具有特定日期的第一个项目上显示日期。 这意味着如果我有 4 个日期为 01/13/2017 的项目，日期应该出现在第一个项目上，而不是在其余 3 个项目上。 有什么想法吗？

Answer 1

使用这种类型的 recyclerView :

1. 确保像这样扩展 RrecyclerViewAdapter RecyclerView.Adapter

2. 创建两个 ViewHolder。

   public class RecyclersViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
   
   ArrayList<Data> arrayList;
   
   Context context;
   
   public final int TYPE_DATE = 0;
   public final int TYPE_CONTENT = 1;
   
   public RecyclersViewAdapter(ArrayList<Data> arrayList, Context context) {
       this.arrayList = arrayList;
       this.context = context;
   }
   
   @Override
   public int getItemViewType(int position) {
   
   
       // Data Class have three fields : Id,Date,Title
   
       if (arrayList.get(position).getId().equals("") && arrayList.get(position).getTitle().equals(""))
           return TYPE_DATE;
       else
           return TYPE_CONTENT;
   }
   
   @NonNull
   @Override
   public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
   
       if (viewType == TYPE_DATE) {
   
           View view = LayoutInflater.from(context).inflate(R.layout.recyc_row,null);
           return new contentViewHolder(view);
   
       } else {
   
           View view1 = LayoutInflater.from(context).inflate(R.layout.recyc_row1,null);
           return new dateViewHolder(view1);
       }
   
   }
   
   @Override
   public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int position) {
   
   
      if(viewHolder instanceof contentViewHolder) {
   
          ((contentViewHolder) viewHolder).id.setText(arrayList.get(position).getId());
          ((contentViewHolder) viewHolder).title.setText(arrayList.get(position).getTitle());
       }
   
       if(viewHolder instanceof dateViewHolder) {
   
        ((dateViewHolder) viewHolder).date.setText(arrayList.get(position).getStartDate());
       }
   
   }
   
   
   public class contentViewHolder extends RecyclerView.ViewHolder {
   
       TextView id,title;
   
       public contentViewHolder(@NonNull View itemView) {
           super(itemView);
   
           id = itemView.findViewById(R.id.tv_id);
           title = itemView.findViewById(R.id.tv_title);
       }
   }
   
   public class dateViewHolder extends RecyclerView.ViewHolder {
       TextView date;
   
       public dateViewHolder(@NonNull View itemView) {
           super(itemView);
   
           date = itemView.findViewById(R.id.tv_date);
       }
   }
   
   @Override
   public int getItemCount() {
       return arrayList.size();
   }