android v7兼容包RecyclerView的使用（一）

什么是RecyclerView？个人理解，它是一个在数据量大的时候，为了显示在界面上提供的灵活高效处理的控件。可以替代listview，gallery，gridview等控件。

如何使用？本篇文章只是热热身，不会过多介绍细节。

首先需要导入\sdk\extras\android\support\v7\recyclerview\libs\android-support-v7-recyclerview.jar包，如果sdk目录下没有该文件，则adt版本可能太低，建议升级或者从网上下载该库。

RecyclerView的使用准备多谢几篇，所以这篇只是入门。

国际惯例，先看效果图，此程序实现微信的会话记录界面。

分析一下，该界面的每一项都是由四个组件构成，即图标，标题，描述，时间。所以，开始编写实体类。

package cn.edu.zafu.recyclerviewdemo;/** * 实体类 * @author lizhangqu * * 2015-3-10 */public class Item {    //图标，简单起见存在本地drawable目录    private int img;    //标题    private String title;    //描述    private String description;    //时间    private String time;    //getter 和 setter    public int getImg() {        return img;    }    public void setImg(int img) {        this.img = img;    }    public String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }    public String getDescription() {        return description;    }    public void setDescription(String description) {        this.description = description;    }    public String getTime() {        return time;    }    public void setTime(String time) {        this.time = time;    }    @Override    public String toString() {        return "Item [img=" + img + ", title=" + title + ", description="                + description + ", time=" + time + "]";    }}

编写完实体类后，开始对每一项的布局进行编写，使用相对布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:paddingBottom="10dp"    android:paddingLeft="15dp"    android:paddingRight="15dp"    android:paddingTop="10dp" >    <ImageView        android:id="@+id/img"        android:layout_width="48dp"        android:layout_height="48dp"        android:layout_alignParentLeft="true"        android:layout_centerVertical="true"        android:background="@drawable/icon" />    <TextView        android:id="@+id/title"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginLeft="10dp"        android:layout_marginTop="5dp"        android:layout_toRightOf="@id/img"        android:text="微信支付"        android:textColor="#000"        android:textSize="16sp" />    <TextView        android:id="@+id/time"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_marginTop="5dp"        android:text="晚上20:09"        android:textColor="#777"        android:textSize="12sp" />    <TextView        android:id="@+id/description"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@id/title"        android:layout_below="@id/title"        android:layout_marginTop="5dp"        android:text="微信支付：支付成功通知" />RelativeLayout>

编写适配器，并编写接口处理点击事件

package cn.edu.zafu.recyclerviewdemo;import java.util.List;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.TextView;import cn.edu.zafu.recyclerviewdemo.RecyclerAdapter.ItemViewHolder;public class RecyclerAdapter extends RecyclerView.Adapter<ItemViewHolder> {    private List items;    //点击监听事件    interface OnRecyclerViewItemClickListener{        void onClick(View view,int position);    };    private OnRecyclerViewItemClickListener listener;    //设置监听器    public void setListener(OnRecyclerViewItemClickListener listener) {        this.listener = listener;    }    //构造函数，将数据赋值给成员变量    public RecyclerAdapter(List items) {        this.items = items;    }    //获得数据大小    @Override    public int getItemCount() {        return items.size();    }    @Override    public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {        //将布局进行绑定        View view = LayoutInflater.from(viewGroup.getContext()).inflate(                R.layout.item, viewGroup, false);        return new ItemViewHolder(view);    }    //绑定数据    @Override    public void onBindViewHolder(final ItemViewHolder viewHolder,final int position) {        Item item = items.get(position);        viewHolder.img.setImageResource(item.getImg());        viewHolder.title.setText(item.getTitle());        viewHolder.description.setText(item.getDescription());        viewHolder.time.setText(item.getTime());        viewHolder.itemView.setOnClickListener(new OnClickListener() {            //如果监听器非空，则回调            @Override            public void onClick(View v) {                if (listener!=null) {                    listener.onClick(viewHolder.itemView, position);                }            }        });    }    //ViewHolder，用于缓存，提高效率    public final static class ItemViewHolder extends RecyclerView.ViewHolder {        //每一项的四个控件        ImageView img;        TextView title;        TextView description;        TextView time;        public ItemViewHolder(View itemView) {            super(itemView);            img = (ImageView) itemView.findViewById(R.id.img);            title = (TextView) itemView.findViewById(R.id.title);            description = (TextView) itemView.findViewById(R.id.description);            time = (TextView) itemView.findViewById(R.id.time);        }    }}

在Activity中使用，为recyclerview设置适配器，数据改变时的动画，

package cn.edu.zafu.recyclerviewdemo;import java.util.ArrayList;import android.app.Activity;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Bundle;import android.support.v7.widget.DefaultItemAnimator;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.view.View;import android.widget.Toast;import cn.edu.zafu.recyclerviewdemo.RecyclerAdapter.OnRecyclerViewItemClickListener;public class MainActivity extends Activity {    private RecyclerView recyclerView;    private ArrayList items = new ArrayList();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);initDatas();        setContentView(R.layout.activity_main);        initDatas();//初始化数据        initViews();//初始化recyclerview    }    private void initViews() {        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);        //新建适配器        RecyclerAdapter adapter = new RecyclerAdapter(items);        //设置监听器        adapter.setListener(new OnRecyclerViewItemClickListener() {            @Override            public void onClick(View view, int position) {                Toast.makeText(getApplicationContext(), items.get(position).getTitle(), Toast.LENGTH_LONG).show();            }        });        //设置适配器        recyclerView.setAdapter(adapter);        //默认动画效果        recyclerView.setItemAnimator(new DefaultItemAnimator());        //设置布局管理器，第三个参数为是否逆向布局        recyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));        //设置每一项的装饰，这里给它加入分隔线        recyclerView.addItemDecoration(new RecyclerView.ItemDecoration() {            Paint paint = new Paint();            @Override            public void onDraw(Canvas c, RecyclerView parent,                    RecyclerView.State state) {                super.onDraw(c, parent, state);            }            @Override            public void onDrawOver(Canvas c, RecyclerView parent,                    RecyclerView.State state) {                super.onDrawOver(c, parent, state);                paint.setColor(Color.LTGRAY);                for (int i = 0, size = parent.getChildCount(); i < size; i++) {                    View child = parent.getChildAt(i);                    c.drawLine(child.getLeft(), child.getBottom(),                            child.getRight(), child.getBottom(), paint);                }            }        });        //可以提高效率        recyclerView.setHasFixedSize(true);    }    private void initDatas() {        Item item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);        item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);        item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);        item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);        item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);        item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);        item = new Item();        item.setImg(R.drawable.icon);        item.setTitle("微信支付");        item.setDescription("微信支付：支付成功通知");        item.setTime("晚上20:35");        items.add(item);    }}

ItemDecoration也可以使用现成的，但是我没有在android源码里找打它，反而是在github上找到的它，这里贴出源码，其作用就是增加分隔线，支持水平和竖直状态，而我的代码只是简单处理了竖直状态下的分隔线

/* * 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. */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);            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);        }    }}

布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <android.support.v7.widget.RecyclerView        android:id="@+id/recyclerView"        android:layout_width="match_parent"        android:layout_height="match_parent" />RelativeLayout>

整个使用过程还是相当简单的，这只是这个控件的使用的开始，而它的作用远远不止这些。更多的内容在之后的博文中详细写。

源码下载
http://download.csdn.net/detail/sbsujjbcy/8489667

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