android v7兼容包RecyclerView的使用（一）

nde7 9年前發布 | 22K 次閱讀 Android開發移動開發 RecyclerView
什么是RecyclerView？個人理解，它是一個在數據量大的時候，為了顯示在界面上提供的靈活高效處理的控件。可以替代listview，gallery，gridview等控件。
如何使用？本篇文章只是熱熱身，不會過多介紹細節。
首先需要導入\sdk\extras\android\support\v7\recyclerview\libs\android- support-v7-recyclerview.jar包，如果sdk目錄下沒有該文件，則adt版本可能太低，建議升級或者從網上下載該庫。
RecyclerView的使用準備多謝幾篇，所以這篇只是入門。
國際慣例，先看效果圖，此程序實現微信的會話記錄界面。
這里寫圖片描述
分析一下，該界面的每一項都是由四個組件構成，即圖標，標題，描述，時間。所以，開始編寫實體類。
package cn.edu.zafu.recyclerviewdemo;
/**

實體類
@author lizhangqu
*
2015-3-10
*/
public class Item {
 //圖標，簡單起見存在本地drawable目錄
 private int img;
 //標題
 private String title;
 //描述
 private String description;
 //時間
 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 + "]";

}


}</pre>

編寫完實體類后，開始對每一項的布局進行編寫，使用相對布局 

<RelativeLayout xmlns:android="

<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></pre>

編寫適配器，并編寫接口處理點擊事件 

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;
    //點擊監聽事件
    interface OnRecyclerViewItemClickListener{
        void onClick(View view,int position);
    };
    private OnRecyclerViewItemClickListener listener;
    //設置監聽器
    public void setListener(OnRecyclerViewItemClickListener listener) {
        this.listener = listener;
    }
    //構造函數，將數據賦值給成員變量
    public RecyclerAdapter(List<Item> items) {
        this.items = items;
    }
    //獲得數據大小
    @Override
    public int getItemCount() {
        return items.size();
    }

@Override
public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
    //將布局進行綁定
    View view = LayoutInflater.from(viewGroup.getContext()).inflate(
            R.layout.item, viewGroup, false);
    return new ItemViewHolder(view);
}
//綁定數據
@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() {
        //如果監聽器非空，則回調
        @Override
        public void onClick(View v) {
            if (listener!=null) {
                listener.onClick(viewHolder.itemView, position);
            }

        }
    });
}
//ViewHolder，用于緩存，提高效率
public final static class ItemViewHolder extends RecyclerView.ViewHolder {
    //每一項的四個控件
    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);
    }
}

}</pre>

在Activity中使用，為recyclerview設置適配器，數據改變時的動畫， 

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();//初始化數據
        initViews();//初始化recyclerview
    }
    private void initViews() {

    recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
    //新建適配器
    RecyclerAdapter adapter = new RecyclerAdapter(items);
    //設置監聽器
    adapter.setListener(new OnRecyclerViewItemClickListener() {

        @Override
        public void onClick(View view, int position) {
            Toast.makeText(getApplicationContext(), items.get(position).getTitle(), Toast.LENGTH_LONG).show();
        }
    });
    //設置適配器
    recyclerView.setAdapter(adapter);
    //默認動畫效果
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    //設置布局管理器，第三個參數為是否逆向布局
    recyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
    //設置每一項的裝飾，這里給它加入分隔線
    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);
}

}</pre>

ItemDecoration也可以使用現成的，但是我沒有在android源碼里找打它，反而是在github上找到的它，這里貼出源碼，其作用就是增加分隔線，支持水平和豎直狀態，而我的代碼只是簡單處理了豎直狀態下的分隔線 

/*

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);
 }

}
}</pre>

布局文件 
<RelativeLayout xmlns:android="
<android.support.v7.widget.RecyclerView

 android:id="@+id/recyclerView"
 android:layout_width="match_parent"
 android:layout_height="match_parent" />


</RelativeLayout></pre>

整個使用過程還是相當簡單的，這只是這個控件的使用的開始，而它的作用遠遠不止這些。更多的內容在之后的博文中詳細寫。 

源碼下載 

http://download.csdn.net/detail/sbsujjbcy/8489667 
來自：http://blog.csdn.net/sbsujjbcy/article/details/44182651
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Android開發移動開發 RecyclerView
android v7兼容包RecyclerView的使用（一）

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