Question

我有一个BaseAdapter类，我正在为扩展BaseAdapter的所有Adapter类中的列表数据实现“刷新”，如下所示：

RecyclerView.Adapter adapter = mRecyclerView.getAdapter();
        if (adapter instanceof "Adapter Class that extends BaseAdapter") {
            ((Adapter Class that extends BaseAdapter") adapter).refreshData(data);
        } else {
            adapter = new Adapter Class that extends BaseAdapter"();
            (("Adapter Class that extends BaseAdapter") adapter).refreshData(topicDetails);
            mRecyclerView.setAdapter(adapter);
        }

其中refreshData(T data)是BaseAdapter中实现notifyDataChanged等的通用抽象方法。

因此，在扩展BaseAdapter的clss中，我可以调用：

public class MyAdapter extends BaseAdapter<Data> {

        @Override
        public void refreshData(Data data) {
            insertItems(data);
            notifyDataSetChanged();
    }

}

在活动/片段或者RecyclerView的任何地方：

mRecyclerView.refreshData(mAdapter)或其他什么。我不确定如何从BaseAdapter中获取“扩展BaseAdapter的适配器类”

tldr

基本上我想写一个通用的方法：

RecyclerView.Adapter adapter = mRecyclerView.getAdapter();
        if (adapter instanceof "Adapter Class that extends BaseAdapter") {
            ((Adapter Class that extends BaseAdapter") adapter).refreshData(data);
        } else {
            adapter = new Adapter Class that extends BaseAdapter"();
            (("Adapter Class that extends BaseAdapter") adapter).refreshData(topicDetails);
            mRecyclerView.setAdapter(adapter);
        }

所以我不必为每个List

执行此操作

Answer 1

首先，此案例与您使用的继承有关。您可以在此处使用通用继承：

RecyclerView.Adapter adapter = mRecyclerView.getAdapter();

if (adapter instanceof BaseAdapter) {
    ((BaseAdapter) adapter).refreshData(topicDetails); //You will get unchecked call here but it won't cause a problem
} else {
    adapter = new BaseAdapter<>();
    ((BaseAdapter) adapter).refreshData(topicDetails); //You will get unchecked call error here but it won't cause a problem
    mRecyclerView.setAdapter(adapter);
}

Answer 2

这是我的BaseAdapter类。

/* general recyclerview adapter */

public abstract class BaseRecyclerAdapter<T, VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> {

    public final List<T> itemList;
    public OnItemClickListener onItemClickListener;

    public BaseRecyclerAdapter(List<T> itemList, OnItemClickListener onItemClickListener) {
        this.itemList = itemList;
        this.onItemClickListener = onItemClickListener;
    }

    public BaseRecyclerAdapter(List<T> itemList) {
        this.itemList = itemList;
    }

    public void clear() {
        itemList.clear();
        notifyDataSetChanged();
    }

    public void add(List<T> itemListToAdd) {
        itemList.addAll(itemListToAdd);
        notifyDataSetChanged();
    }


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

    public interface OnItemClickListener<Object> {
        void onItemClick(View view, Object object);
    }
}

并像

一样使用它

public class AdapterDemo extends BaseRecyclerAdapter<BeanCart,AdapterDemo.MyViewHolder> {


    public AdapterDemo(List<BeanCart> itemList) {
        super(itemList);
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {

    }
    class MyViewHolder extends RecyclerView.ViewHolder {


        MyViewHolder(View itemView) {
            super(itemView);
        }
    }
}

在这里你将传递两个类类型

T＆GT;清单类型

VH＆GT;查看持有人

喜欢这个public class AdapterDemo extends BaseRecyclerAdapter<BeanCart,AdapterDemo.MyViewHolder>

如何使用泛型从Base类中获取扩展Base类的类？

2 个答案: