Android 创建自定义 RecyclerView.Adapter 并从中创建其他 Class

Question

各位，我有一个从 WebService 填充的 RecyclerView，还有一个管理异步请求的 DataProvider class。因此，当获取数据时，我需要此 DataProvider 通知 RecyclerView.Adapter 有新数据。为此，我需要向 RecyclerView.Adapter 添加一个允许此通信的方法。但是当我创建一个基础class（扩展RecyclerView.Adapter）并在其中创建自定义适配器时，它不会让我重写RecyclerView.Adapter 方法。我做错了什么？

这是基础class

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

public static class ViewHolder extends RecyclerView.ViewHolder{

    public ViewHolder (View v){
        super(v);
    }
}

public BaseRecyclerAdapter(RecyclerView rv){

}

public void setDataSet( String data) {
   //This is the method i need to add
}

}

这是扩展 BaseRecyclerAdapter 的自定义适配器

public class PlacesAdapter extends BaseRecyclerAdapter<PlacesAdapter.ViewHolder> {

public static class ViewHolder extends RecyclerView.ViewHolder{
    public TextView mTextView;
    public ViewHolder(View v){
        super(v);
        mTextView= (TextView) v.findViewById(R.id.info_text);
    }
}

public PlacesAdapter(RecyclerView recyclerView){
    super(recyclerView);
}
@Override
public int getItemCount() {
    return 0;
}

@Override
public void setDataSet( String data) {

}

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    //This says Method does not override method from its suplerclass
}

}

我猜这与类型参数有关，但我无法弄清楚是怎么回事

Answer 1

查看来自 Pascal Welsch 的要点：

当我第一次开始使用 RecyclerView 而不是 ListView 时，这对我很有帮助。

import android.support.v7.widget.RecyclerView;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 * Created by pascalwelsch on 04.07.14.
 */
public abstract class ArrayAdapter<T, VH extends RecyclerView.ViewHolder>
        extends RecyclerView.Adapter<VH> {

    private List<T> mObjects;

    public ArrayAdapter(final List<T> objects) {
        mObjects = objects;
    }

    /**
     * Adds the specified object at the end of the array.
     *
     * @param object The object to add at the end of the array.
     */
    public void add(final T object) {
        mObjects.add(object);
        notifyItemInserted(getItemCount() - 1);
    }

    /**
     * Remove all elements from the list.
     */
    public void clear() {
        final int size = getItemCount();
        mObjects.clear();
        notifyItemRangeRemoved(0, size);
    }

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

    public T getItem(final int position) {
        return mObjects.get(position);
    }

    public long getItemId(final int position) {
        return position;
    }

    /**
     * Returns the position of the specified item in the array.
     *
     * @param item The item to retrieve the position of.
     * @return The position of the specified item.
     */
    public int getPosition(final T item) {
        return mObjects.indexOf(item);
    }

    /**
     * Inserts the specified object at the specified index in the array.
     *
     * @param object The object to insert into the array.
     * @param index  The index at which the object must be inserted.
     */
    public void insert(final T object, int index) {
        mObjects.add(index, object);
        notifyItemInserted(index);

    }

    /**
     * Removes the specified object from the array.
     *
     * @param object The object to remove.
     */
    public void remove(T object) {
        final int position = getPosition(object);
        mObjects.remove(object);
        notifyItemRemoved(position);
    }

    /**
     * Sorts the content of this adapter using the specified comparator.
     *
     * @param comparator The comparator used to sort the objects contained in this adapter.
     */
    public void sort(Comparator<? super T> comparator) {
        Collections.sort(mObjects, comparator);
        notifyItemRangeChanged(0, getItemCount());
    }
}

来源： https://gist.github.com/passsy/f8eecc97c37e3de46176

Answer 2

谢谢 Jared 这对我帮助很大

最后 BaseRecyclerAdapter 看起来像这样：

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

public static class VH extends RecyclerView.ViewHolder{

    public VH (View v){
        super(v);
    }
}

public BaseRecyclerAdapter(RecyclerView rv){

}

public void setDataSet( String data) {
   //this is the special method added
}
}

现在您可以覆盖 RecyclerView.Adapter 中您喜欢的任何方法并实现特殊方法