RecyclerView通用适配器的实现

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分析

我们需要在RecyclerViewAdapter内部维持一个数据集合的引用
需要实现Item的点击事件，包括短按和长按，并需要向外部提供设置监听器的方法
这个适配器必须通用，所以应该是泛型的，并且ViewHolder也是通用的，可以采用SparseArray维持View的所有集合
在RecyclerViewAdapter内部需要实现数据的绑定（抽象方法，延迟到子类实现），监听器的绑定

编写监听器

分为短按事件和长按事件

短按监听器

package cn.edu.zafu.base.adapter.listener;import android.view.View;/** * Created by lizhangqu on 2015/6/3. */public interface OnItemClickListener<T> {    void onClick(View view, T item);}

长按监听器

package cn.edu.zafu.base.adapter.listener;import android.view.View;/** * Created by lizhangqu on 2015/6/3. */public interface OnItemLongClickListener<T> {    void onLongClick(View view, T item);}

编写通用适配器

设置监听器

package cn.edu.zafu.base.adapter;import android.support.v7.widget.RecyclerView;import android.util.SparseArray;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.TextView;import java.util.List;import cn.edu.zafu.base.adapter.listener.OnItemClickListener;import cn.edu.zafu.base.adapter.listener.OnItemLongClickListener;/** * this is a BaseAdapter for RecyclerView * author lizhangqu * version 1.0 * date 2015/6/3. */public abstract class BaseRecyclerViewAdapter<T, VH extends BaseRecyclerViewAdapter.SparseArrayViewHolder> extends RecyclerView.Adapter<VH> {    /**     * click listener     */    protected OnItemClickListener mOnItemClickListener;    /**     * long click listener     */    protected OnItemLongClickListener mOnItemLongClickListener;    /**     * set a long click listener     *     * @param onItemLongClickListener     */    public void setOnItemLongClickListener(OnItemLongClickListener onItemLongClickListener) {        mOnItemLongClickListener = onItemLongClickListener;    }    /**     * set a click listener     *     * @param onItemClickListener     */    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {        mOnItemClickListener = onItemClickListener;    }}

编写构造方法，将数据集合进行赋值

    /**     * data     */    protected List<T> mList;    /**     * @param list the datas to attach the adapter     */    public BaseRecyclerViewAdapter(List<T> list) {        mList = list;    }

实现几个必要的方法，比如获得Item以及覆写getItemCount方法

 /** * get a item by index * * @param position * @return */protected T getItem(int position) {    return mList.get(position);}@Overridepublic int getItemCount() {    return mList.size();}

实现将布局文件映射成View的方法

   /**     * inflate a view by viewgroup ,id ,etc     *     * @param viewGroup     * @param layoutId     * @return     */    protected View inflateItemView(ViewGroup viewGroup, int layoutId) {        return inflateItemView(viewGroup, layoutId, false);    }    /**     * inflate a view by viewgroup ,id ,etc     *     * @param viewGroup     * @param layoutId     * @param attach     * @return     */    protected View inflateItemView(ViewGroup viewGroup, int layoutId, boolean attach) {        return LayoutInflater.from(viewGroup.getContext()).inflate(layoutId, viewGroup, attach);    }

实现onBindViewHolder方法，这一步很重要，将具体实现抽取到两个方法中去实现，bindDataToItemView是一个抽象方法，延迟到子类实现，bindItemViewClickListener方法设置监听器

  /**     * a final function to avoid you override     * use template design pattern     *     * @param vh     * @param position     */    @Override    public final void onBindViewHolder(VH vh, int position) {        final T item = getItem(position);        bindDataToItemView(vh, item);        bindItemViewClickListener(vh, item);    }    /**     * bind data to itemview     *     * @param vh   viewholder     * @param item item     */    protected abstract void bindDataToItemView(VH vh, T item);    /**     * bind click listner to itemview     *     * @param vh   viewholder     * @param item item     */    protected final void bindItemViewClickListener(VH vh, final T item) {        if (mOnItemClickListener != null) {            vh.itemView.setOnClickListener(new View.OnClickListener() {                @Override                public void onClick(View view) {                    mOnItemClickListener.onClick(view, item);                }            });        }        if (mOnItemLongClickListener != null) {            vh.itemView.setOnLongClickListener(new View.OnLongClickListener() {                @Override                public boolean onLongClick(View v) {                    mOnItemLongClickListener.onLongClick(v, item);                    return true;                }            });        }    }

实现通用ViewHolder，内部使用SparseArray维持View对象

    public static class SparseArrayViewHolder extends RecyclerView.ViewHolder {        private final SparseArray<View> views;        public SparseArrayViewHolder(View itemView) {            super(itemView);            views = new SparseArray<View>();        }        public <T extends View> T getView(int id) {            View view = views.get(id);            if (view == null) {                view = itemView.findViewById(id);                views.put(id, view);            }            return (T) view;        }    }

内部实现了一个泛型的getView方法，其作用就是将View缓存至SparseArray中去

实现通用ViewHolder的一些属性设置方法，采用链式调用，返回this对象

        public SparseArrayViewHolder setText(int viewId, String value) {            TextView view = getView(viewId);            view.setText(value);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setTextColor(int viewId, int textColor) {            TextView view = getView(viewId);            view.setTextColor(textColor);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setImageResource(int viewId, int imageResId) {            ImageView view = getView(viewId);            view.setImageResource(imageResId);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setBackgroundColor(int viewId, int color) {            View view = getView(viewId);            view.setBackgroundColor(color);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setBackgroundResource(int viewId, int backgroundRes) {            View view = getView(viewId);            view.setBackgroundResource(backgroundRes);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setVisible(int viewId, boolean visible) {            View view = getView(viewId);            view.setVisibility(visible ? View.VISIBLE : View.GONE);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setOnClickListener(int viewId, View.OnClickListener listener) {            View view = getView(viewId);            view.setOnClickListener(listener);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setOnTouchListener(int viewId, View.OnTouchListener listener) {            View view = getView(viewId);            view.setOnTouchListener(listener);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setOnLongClickListener(int viewId, View.OnLongClickListener listener) {            View view = getView(viewId);            view.setOnLongClickListener(listener);            return SparseArrayViewHolder.this;        }        public SparseArrayViewHolder setTag(int viewId, Object tag) {            View view = getView(viewId);            view.setTag(tag);            return SparseArrayViewHolder.this;        }

源码

参见github地址：https://github.com/lizhangqu

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