Android程序设计-RecyclerView的使用

【定义】

看到这个标题，也许你会问什么是RecyclerView?其实开始的时候我也不知道- -，下面小编将带领大家领略RecyclerView的强大之处

【描述】

看完这个我想大家应该知道了吧，这个东西和ListView一样，只不过，这个…在设计的时候不需要考虑上述几个功能，即使要实现这几个功能，也是很简单的，仅仅需要几句话就可以搞定的

【使用】

使用的时候需要导入recyclerview-v7-21.0.0的jar包，然后在布局文件中添加这个控件

<android.support.v7.widget.RecyclerView/>

---------------------------------------------------------------我是一个帅帅的分割线-------------------------------------------------------

【案例】

小编将通过一个案例实现RecyclerView的使用，下面请看这个案例的实现效果

【关键步骤】

1.在布局文件中添加了对用的控件后，我们需要书写代码，既然和ListView肯定需要适配器，下面我们来看下适配器

package org.monster.recyclerviewdemo;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.List;

/**
 * Created by monster on 2015/7/9.
 * 继承RecyclerView，实现ListView的效果
 * RecyclerView中google强烈要求使用ViewHolder
 */
public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder>{
    private List<String> mData;
    private Context context;
    private LayoutInflater mInflater;

    /**
     * 声明一个接口，用于实现点击事件
     */
    public interface  OnItemClickListener{
        void OnItemClick(int position,View view);
        void OnItemLongClick(int position,View view);
    }

    private OnItemClickListener mOnItemClickListener;

    public  void setOnItemClickListener(OnItemClickListener listener){
        this.mOnItemClickListener=listener;
    }

    /**构造方法的实现**/

    public SimpleAdapter(List<String> mData,Context context){
        this.mData=mData;
        this.context=context;
        mInflater=LayoutInflater.from(context);
    }

    /**
     * 创建ViewHolder
     * @param parent
     * @param viewType
     * @return
     */
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view=mInflater.inflate(R.layout.recycler_item,parent,false);
        MyViewHolder viewHolder=new MyViewHolder(view);
        return viewHolder;
    }

    /**
     * 绑定ViewHolder类,即给控件赋值
     * @param holder
     * @param position
     */
    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        holder.tv.setText(mData.get(position));
        if (mOnItemClickListener!=null){

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

                @Override
                public void onClick(View v) {
                    int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                    mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView);

                }
            });

            //longclickListener
            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                    mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView);
                    return false;
                }
            });
        }

    }

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

    public void addData(int position){
        mData.add(position,"Insert One");
        notifyItemInserted(position);
    }

    public void deleteData(int position){
        mData.remove(position);
        notifyItemRemoved(position);
    }
}

/**
 * ViewHolder类，这个类的作用主要用于实例化控件
 */
    class MyViewHolder extends RecyclerView.ViewHolder{
        TextView tv; //声明控件
        public MyViewHolder(View itemView) {
            super(itemView);
            /**初始化控件**/
            tv= (TextView) itemView.findViewById(R.id.tv);
        }
    }

ps:

代码中我们可以看到我们继承了RecyclerView.Adapter<MyViewHolder>，实现了未实现的方法，但是一定要注意，google在这里要求必须实现ViewHolder这个类，我们通过代码知道，通过设计了ViewHolder使我们的类更加的简洁了，更重要的是我们的代码更加的实用了。

2.我们来看下MainActivity中的代码：

package org.monster.recyclerviewdemo;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Switch;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends ActionBarActivity {
    private RecyclerView recyclerView;
    private List<String> mDatas;
    private SimpleAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initDatas();

        initView();

        adapter=new SimpleAdapter(mDatas,this);
        recyclerView.setAdapter(adapter);

        //设置RecyclerView的布局管理
        LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
        recyclerView.setLayoutManager(layoutManager);

        //设置RecyclerView的item间的分割线
       // recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));

        //设置RecyclerView的动画
        recyclerView.setItemAnimator(new DefaultItemAnimator());

        //设置监听事件
        adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
            @Override
            public void OnItemClick(int position, View view) {
                Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void OnItemLongClick(int position, View view) {
                Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show();
            }
        });
    }

    private void initView() {
        recyclerView= (RecyclerView) findViewById(R.id.RecyclerView);

    }

    /**
     * 加载数据源
     */
    private void initDatas() {
        mDatas=new ArrayList<String>();
        for(int i='A';i<'z';i++){
            mDatas.add(" "+(char)i);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        switch (id){
            case R.id.action_add:
                adapter.addData(1);
                break;

            case R.id.action_delete:
                adapter.deleteData(1);
                break;
            case R.id.action_listview:
                recyclerView.setLayoutManager(new LinearLayoutManager(this));
                break;
            case R.id.action_gridview:
                recyclerView.setLayoutManager(new GridLayoutManager(this,3));
                break;
            case R.id.action_hor_gridview:
                recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.HORIZONTAL));
                break;
            case R.id.action_staggered:
                Intent i=new Intent(this,StaggerActivity.class);
                startActivity(i);
                break;

        }

        return super.onOptionsItemSelected(item);
    }
}

PS:

适配器的使用和ListView的使用一样，但是这时候当我们运行程序会发现没有分割线，整个页面成一个了，所以我们需要使用addItemDecoration添加分割线

      设置RecyclerView的item间的分割线
       recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));

Comic Sans MS在分割线的部分我们需要引入github中的一个分割线文件：

package org.monster.recyclerviewdemo;

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;

/**
 * This class is from the v7 samples of the Android SDK. It's not by me!
 * <p/>
 * See the license above for details.
 */
public class DividerItemDecoration extends RecyclerView.ItemDecoration
{

    private static final int[] ATTRS = new int[] { android.R.attr.listDivider };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private Drawable mDivider;

    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation)
    {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public void setOrientation(int orientation)
    {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST)
        {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent)
    {
         if (mOrientation == VERTICAL_LIST) {
                drawVertical(c, parent);
            } else {
                drawHorizontal(c, parent);
            }
    }

    public void drawVertical(Canvas c, RecyclerView parent)
    {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();

        for (int i = 0; i < childCount; i++)
        {
            final View child = parent.getChildAt(i);
            RecyclerView v = new RecyclerView(
                    parent.getContext());
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawHorizontal(Canvas c, RecyclerView parent)
    {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++)
        {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition,
            RecyclerView parent)
    {
        if (mOrientation == VERTICAL_LIST)
        {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else
        {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }
}

如何在RecyleView中设计布局管理？这个布局管理可以让你的页面实现ListView和GridView的自由切换

       //设置RecyclerView的布局管理
        LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
        recyclerView.setLayoutManager(layoutManager);

如何咋RecyclerView中增加添加item和删除item的动画？

（附录动画效果的Github链接：https://github.com/gabrielemariotti/RecyclerViewItemAnimators）

      //设置RecyclerView的动画
        recyclerView.setItemAnimator(new DefaultItemAnimator());

如何在对Recycler中的item设置监听事件？这个监听事件系统不提供，需要我们手动编写

--->我们需要在适配器添加一个接口：

/**
     * 声明一个接口，用于实现点击事件
     */
    public interface  OnItemClickListener{
        void OnItemClick(int position,View view);
        void OnItemLongClick(int position,View view);
    }

    private OnItemClickListener mOnItemClickListener;

    public  void setOnItemClickListener(OnItemClickListener listener){
        this.mOnItemClickListener=listener;
    }

    /**构造方法的实现**/

    public SimpleAdapter(List<String> mData,Context context){
        this.mData=mData;
        this.context=context;
        mInflater=LayoutInflater.from(context);
    }

--->在onBindViewHolder中设置监听事件的方法

/**
     * 绑定ViewHolder类,即给控件赋值
     * @param holder
     * @param position
     */
    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        holder.tv.setText(mData.get(position));
        if (mOnItemClickListener!=null){

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

                @Override
                public void onClick(View v) {
                    int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                    mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView);

                }
            });

            //longclickListener
            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
                    mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView);
                    return false;
                }
            });
        }

    }

--->>在MainActivity中调用如

//设置监听事件
        adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
            @Override
            public void OnItemClick(int position, View view) {
                Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void OnItemLongClick(int position, View view) {
                Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show();
            }
        });

上述即为RecyclerView的简单实用，程序中的其他样式敬请参考【源码】

【视频】

http://www.imooc.com/learn/424

【源码】

https://github.com/monsterLin/recyclerviewdemo