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<Item> 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<Item> 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<Item> items = new ArrayList<Item>();      @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);          }      }  }

<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