RecycleView的万能适配器

转载自http://www.cnblogs.com/liushilin/p/5720926.html

由于RecyclerView的Adapter必须继承自RecyclerView.Adapter，并且指定我们写的ViewHolder为泛型，为了达到万能的效果，我们把需要传入的Java Bean属性直接用一个泛型T指代。

下面这些值得你注意：

1）RecyclerView没有提供Item的点击事件，所以我们需要自己自定义，建议实现在Adapter中，因为adapter里面会用到ViewHolder，这样有助用我们写每一项的点击事件。

2）RecyclerView不仅支持全局刷新，而且支持局部刷新，所以我们建议把添加和删除的方法直接写在Adapter中。

3）我们为了达到万能的效果，所以我们把设置holder的方法作为一个抽象方法，方面我们通过viewId传值到相应的控件中，把整个Adapter变成一个抽象方法，这样在子类中就可以去通过强制实现的方式把我们的数据填充进去。

还是直接看源码吧。

 package com.example.nanchen.commonadaperrecyclerdemo;

 import android.content.Context;

 import android.support.v7.widget.RecyclerView;

 import android.view.LayoutInflater;

 import android.view.View;

 import android.view.ViewGroup;

 import java.util.List;

 /**

  * 万能的RecyclerView适配器

  * Created by 南尘 on 16-7-30.

  */

 public abstract class BaseRecyclerAdapter<T> extends RecyclerView.Adapter<BaseRecyclerHolder> {

     private Context context;//上下文

     private List<T> list;//数据源

     private LayoutInflater inflater;//布局器

     private int itemLayoutId;//布局id

     private boolean isScrolling;//是否在滚动

     private OnItemClickListener listener;//点击事件监听器

     private OnItemLongClickListener longClickListener;//长按监听器

     private RecyclerView recyclerView;

     //在RecyclerView提供数据的时候调用

     @Override

     public void onAttachedToRecyclerView(RecyclerView recyclerView) {

         super.onAttachedToRecyclerView(recyclerView);

         this.recyclerView = recyclerView;

     }

     @Override

     public void onDetachedFromRecyclerView(RecyclerView recyclerView) {

         super.onDetachedFromRecyclerView(recyclerView);

         this.recyclerView = null;

     }

     /**

      * 定义一个点击事件接口回调

      */

     public interface OnItemClickListener {

         void onItemClick(RecyclerView parent, View view, int position);

     }

     public interface OnItemLongClickListener {

         boolean onItemLongClick(RecyclerView parent, View view, int position);

     }

     /**

      * 插入一项

      *

      * @param item

      * @param position

      */

     public void insert(T item, int position) {

         list.add(position, item);

         notifyItemInserted(position);

     }

     /**

      * 删除一项

      *

      * @param position 删除位置

      */

     public void delete(int position) {

         list.remove(position);

         notifyItemRemoved(position);

     }

     public BaseRecyclerAdapter(Context context, List<T> list, int itemLayoutId) {

         this.context = context;

         this.list = list;

         this.itemLayoutId = itemLayoutId;

         inflater = LayoutInflater.from(context);

         //        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {

         //            @Override

         //            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {

         //                super.onScrollStateChanged(recyclerView, newState);

         //                isScrolling = !(newState == RecyclerView.SCROLL_STATE_IDLE);

         //                if (!isScrolling) {

         //                    notifyDataSetChanged();

         //                }

         //            }

         //        });

     }

     @Override

     public BaseRecyclerHolder onCreateViewHolder(ViewGroup parent, int viewType) {

         View view = inflater.inflate(itemLayoutId, parent, false);

         return BaseRecyclerHolder.getRecyclerHolder(context, view);

     }

     @Override

     public void onBindViewHolder(final BaseRecyclerHolder holder, int position) {

         if (listener != null){

             holder.itemView.setBackgroundResource(R.drawable.recycler_bg);//设置背景

         }

         holder.itemView.setOnClickListener(new View.OnClickListener() {

             @Override

             public void onClick(View view) {

                 if (listener != null && view != null && recyclerView != null) {

                     int position = recyclerView.getChildAdapterPosition(view);

                     listener.onItemClick(recyclerView, view, position);

                 }

             }

         });

         holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {

             @Override

             public boolean onLongClick(View view) {

                 if (longClickListener != null && view != null && recyclerView != null) {

                     int position = recyclerView.getChildAdapterPosition(view);

                     longClickListener.onItemLongClick(recyclerView, view, position);

                     return true;

                 }

                 return false;

             }

         });

         convert(holder, list.get(position), position, isScrolling);

     }

     @Override

     public int getItemCount() {

         return list == null ? 0 : list.size();

     }

     public void setOnItemClickListener(OnItemClickListener listener) {

         this.listener = listener;

     }

     public void setOnItemLongClickListener(OnItemLongClickListener longClickListener) {

         this.longClickListener = longClickListener;

     }

     /**

      * 填充RecyclerView适配器的方法，子类需要重写

      *

      * @param holder      ViewHolder

      * @param item        子项

      * @param position    位置

      * @param isScrolling 是否在滑动

      */

     public abstract void convert(BaseRecyclerHolder holder, T item, int position, boolean isScrolling);

 }

其他的代码就很简单了，java bean类Data和布局和昨天一样的，大家可以自己去随便怎么布局。

这里只上一个MainActivity的代码

 package com.example.nanchen.commonadaperrecyclerdemo;

 import android.os.Bundle;

 import android.support.v7.app.AppCompatActivity;

 import android.support.v7.widget.LinearLayoutManager;

 import android.support.v7.widget.RecyclerView;

 import android.view.View;

 import android.widget.EditText;

 import android.widget.Toast;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.Locale;

 public class MainActivity extends AppCompatActivity {

     private List<Data> list;

     private RecyclerView recyclerView;

     private BaseRecyclerAdapter<Data> adapter;

     private EditText text;

     @SuppressWarnings("unchecked")

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         list = new ArrayList<>();

         initList();

         adapter = new BaseRecyclerAdapter<Data>(this,list,R.layout.list_item) {

             @Override

             public void convert(BaseRecyclerHolder holder, Data item, int position, boolean isScrolling) {

                 holder.setText(R.id.item_text,item.getText());

                 if (item.getImageUrl() != null){

                     holder.setImageByUrl(R.id.item_image,item.getImageUrl());

                 }else {

                     holder.setImageResource(R.id.item_image,item.getImageId());

                 }

             }

         };

         adapter.setOnItemClickListener(new BaseRecyclerAdapter.OnItemClickListener() {

             @Override

             public void onItemClick(RecyclerView parent, final View view, int position) {

                 Toast.makeText(MainActivity.this, String.format(Locale.CHINA,"你点击了第%d项,长按会删除！",position),Toast.LENGTH_SHORT).show();

             }

         });

         adapter.setOnItemLongClickListener(new BaseRecyclerAdapter.OnItemLongClickListener() {

             @Override

             public boolean onItemLongClick(RecyclerView parent, View view, int position) {

                 adapter.delete(position);

                 return true;

             }

         });

         text = (EditText) findViewById(R.id.main_text);

         recyclerView = (RecyclerView) findViewById(R.id.main_recycler);

         recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));

         recyclerView.setAdapter(adapter);

     }

     public void initList(){

         for (int i = 0; i < 5; i++) {

             list.add(new Data("本地 "+i,R.mipmap.ic_launcher));

         }

         for (int i = 0; i < 5; i++) {

             list.add(new Data("网络 "+i,"http://pic.cnblogs.com/face/845964/20160301162812.png"));

         }

     }

     public void btnClick(View view) {

         String string = text.getText().toString().trim();

         Data data = new Data(string,R.mipmap.ic_launcher);

 //        list.add(list.size()/2,data);

         adapter.insert(data,list.size()/2);

         Toast.makeText(MainActivity.this,list.size()+"",Toast.LENGTH_SHORT).show();

     }

 }

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RecycleView的万能适配器

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