RecyclerView OnCreateViewWholder返回类型与多个自定义ViewWholder不兼容

Question

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

    public TextView menuItemText;
    public ImageView menuItemPhoto;
    public RecyclerViewAdapter rva;

    public MenuItemViewHolder(View itemView) {
         super(itemView);
         itemView.setOnClickListener(this);

         rva = caller;
         menuItemText = (TextView) itemView.findViewById(R.id.grid_text);
         menuItemPhoto = (ImageView) itemView.findViewById(R.id.grid_image);
    }

    @Override
    public void onClick(View view) {
          Toast.makeText(view.getContext(), "Clicked Position = " + getPosition(), Toast.LENGTH_SHORT).show();

    }

}

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

    public TextView menuItemText;
    public ImageView menuItemPhoto;
    public RecyclerViewAdapter rva;

    public SelectedItemViewHolder(View itemView) {
        super(itemView);
        itemView.setOnClickListener(this);

         menuItemText = (TextView) itemView.findViewById(R.id.grid_text_full);
         menuItemPhoto = (ImageView) itemView.findViewById(R.id.grid_image_full);
    }

    @Override
    public void onClick(View view) {
          Toast.makeText(view.getContext(), "Clicked Position = " + getPosition(), Toast.LENGTH_SHORT).show();
    }
}

// Create new views (invoked by the layout manager)

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        switch (viewType) {

            case 0:
                View gridItemLayout = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.grid_single, parent, false);
                // set the view's size, margins, paddings and layout parameters
                MenuItemViewHolder vh = new MenuItemViewHolder(gridItemLayout);

            case 2:
                View selectedItemLayout = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.grid_single_full, parent, false);
                // set the view's size, margins, paddings and layout parameters
                SelectedItemViewHolder sivh = new SelectedItemViewHolder(selectedItemLayout);
                return sivh;
          }
    }

当我尝试运行代码时,我得到以下错误：

错误：（48,36）错误：RecyclerViewAdapter中的OnCreateViewWholder（ViewGroup,int）无法重写适配器中的OnCreateViewWholder（ViewGroup,int）返回类型ViewWholder与MenuItemViewWholder不兼容,其中VH是类型变量：VH扩展类Adapter中声明的ViewWholder

所以，问题似乎是OnCreateViewWholder不接受我的自定义类是从RecyclerView.ViewWholder继承的。我使用的是Android Studio，所以也许问题就在那里。我很困惑，因为我以为Java继承可以处理这件事，不会有任何问题。有人能提出一个解决办法吗？

编辑：当我将OnCreateViewWholder的返回类型更改为MenuItemViewWholder仅使用一个VH时，一切工作都很好。但是，当我有多个可以随时交换的VH类时，这就不起作用了。

Answer 1

RecyclerView.Adapter是一个参数化类，它接受单个ViewWholder类型。您的定义可能如下所示：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MenuItemViewHolder>

应该是：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>

别忘了为OnBindViewWholder提供正确的定义。您还需要重写GetItemViewType。