使用自定义的item、Adapter和AsyncTask、第三方开源框架PullToRefresh联合使用实现自定义的下拉列表（从网络加载图片显示在item中的ImageView）

AsyncTask使用方法详情：http://www.cnblogs.com/zzw1994/p/4959949.html

下拉开源框架PullToRefresh使用方法和下载详情：http://www.cnblogs.com/zzw1994/p/4992194.html

具体实现的代码如下：

item.xml：

 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
      >

     <ImageView
         android:id="@+id/imageView1"
         android:layout_width="50dp"
         android:layout_height="50dp"
         android:layout_alignParentLeft="true"
         android:src="@drawable/ic_launcher" />

     <TextView
         android:id="@+id/textView"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignBottom="@+id/imageView1"
         android:layout_alignParentTop="true"
         android:layout_toLeftOf="@+id/imageView2"
         android:layout_toRightOf="@+id/imageView1"
         android:gravity="center"
         android:text="TextView"
        android:textColor="@android:color/holo_red_light"
         android:textSize="30sp" />

     <ImageView
         android:id="@+id/imageView2"
         android:layout_width="50dp"
         android:layout_height="50dp"
         android:layout_alignParentRight="true"
         android:layout_alignParentTop="true"
         android:src="@drawable/ic_launcher" />

 </RelativeLayout>

item.xml

activity_main.xml:

 <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"
     tools:context="com.zzw.testpulltorefresh.MainActivity" >

     <com.handmark.pulltorefresh.library.PullToRefreshListView
         android:id="@+id/listView"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />

 </RelativeLayout>

activity_main.xml

MainActivity.java:

 package com.zzw.testpulltorefresh;

 import java.io.BufferedInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.HashMap;

 import com.handmark.pulltorefresh.library.PullToRefreshBase;
 import com.handmark.pulltorefresh.library.PullToRefreshBase.Mode;
 import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener;
 import com.handmark.pulltorefresh.library.PullToRefreshListView;

 import android.app.Activity;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.Color;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ArrayAdapter;
 import android.widget.ImageView;
 import android.widget.ListView;
 import android.widget.TextView;
 import android.widget.Toast;

 public class MainActivity extends Activity {
     private int COUNT = 0;

     private final String IMAGE_KEY1 = "IMAGE_KEY1";
     private final String IMAGE_KEY2 = "IMAGE_KEY2";
     private final String TEXT_KEY = "TEXT_KEY";

     private PullToRefreshListView listView;
     private ArrayList<HashMap<String, Object>> data;
     private ArrayAdapter adapter;
     private String[] urls = { "http://p1.so.qhimg.com/bdr/_240_/t01829c584b50b68311.jpg",
             "http://p2.so.qhimg.com/bdr/_240_/t011c2cd4fe8723bcb2.jpg",
             "http://p4.so.qhimg.com/bdr/_240_/t01b11db3c0961b24a9.jpg",
             "http://p4.so.qhimg.com/bdr/_240_/t019786092c7b1688b9.jpg",
             "http://p4.so.qhimg.com/bdr/_240_/t015b226d64a10097ce.jpg",
             "http://p1.so.qhimg.com/bdr/_240_/t01f6c4382c907133ab.jpg" };

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         data = new ArrayList<HashMap<String, Object>>();

         listView = (PullToRefreshListView) findViewById(R.id.listView);

         // 设置向下滑动时刷新
         listView.setMode(Mode.PULL_FROM_START);
         // 支持下拉和上拉 listView.setMode(Mode.BOTH);

         // 设置监听
         listView.setOnRefreshListener(new OnRefreshListener<ListView>() {

             @Override
             public void onRefresh(PullToRefreshBase<ListView> refreshView) {
                 // 在这完成业务逻辑
                 new MyAsyncTask().execute();
             }
         });

         adapter = new MyAdapter(this, R.layout.item);
         listView.setAdapter(adapter);

         // 设置如果数据为空的时候显示什么
         TextView textView = new TextView(this);
         textView.setText("请下拉刷新");
         listView.setEmptyView(textView);
     }

     //自定义的Item显示参数设置在Adapter中操作
     private class MyAdapter extends ArrayAdapter {

         private LayoutInflater inflater;
         private int item;

         public MyAdapter(Context context, int resource) {
             super(context, resource);
             inflater = LayoutInflater.from(context);
             this.item = resource;
         }

         @Override
         public int getCount() {
             return data.size();
         }

         @Override
         public HashMap<String, Object> getItem(int position) {

             return data.get(position);
         }

         @Override
         public View getView(int position, View convertView, ViewGroup parent) {
             HashMap<String, Object> map = getItem(position);

             if (convertView == null) {
                 convertView = inflater.inflate(item, null);
             }

             ImageView image1 = (ImageView) convertView.findViewById(R.id.imageView1);
             ImageView image2 = (ImageView) convertView.findViewById(R.id.imageView2);
             TextView textView = (TextView) convertView.findViewById(R.id.textView);

             image1.setImageBitmap((Bitmap) map.get(IMAGE_KEY1));
             image2.setImageBitmap((Bitmap) map.get(IMAGE_KEY2));
             textView.setText(map.get(TEXT_KEY) + "");

             if (position % 2 == 1) {
                 textView.setTextColor(Color.BLUE);
             }

             return convertView;
         }

     }

     //联网等一系列延时操作在AsyncTask中操作
     private class MyAsyncTask extends AsyncTask {

         @Override
         protected void onPreExecute() {
             // 开始刷新
             listView.setRefreshing();
         }

         @Override
         protected Object doInBackground(Object... params) {
             HashMap<String, Object> map = new HashMap<String, Object>();
             try {
                 byte[] buf = loadRawDataFromURL(urls[COUNT]);
                 BitmapFactory factory = new BitmapFactory();
                 Bitmap bitmap = factory.decodeByteArray(buf, 0, buf.length);
                 map.put(TEXT_KEY, "数据->" + COUNT);
                 map.put(IMAGE_KEY1, bitmap);
                 map.put(IMAGE_KEY2, bitmap);
             } catch (Exception e) {
                 e.printStackTrace();
             }
             return map;
         }

         @Override
         protected void onPostExecute(Object result) {

             data.add(0,(HashMap<String, Object>) result);
             adapter.notifyDataSetChanged();

             // 设置标签
             listView.setLastUpdatedLabel("最后更新新的时间：" + new Date());

             // 刷新完成
             listView.onRefreshComplete();
             COUNT++;
             if (COUNT >= urls.length) {
                 COUNT = 0;
             }
             Toast.makeText(getApplicationContext(), "加载成功", 0).show();
         }
     }

     // 通过URL读取字节数组
     public static byte[] loadRawDataFromURL(String u) throws Exception {
         URL url = new URL(u);
         HttpURLConnection conn = (HttpURLConnection) url.openConnection();

         InputStream is = conn.getInputStream();
         BufferedInputStream bis = new BufferedInputStream(is);

         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         // 缓存2KB
         final int BUFFER_SIZE = 2 * 1024;
         final int EOF = -1;

         int c;
         byte[] buf = new byte[BUFFER_SIZE];

         while (true) {
             c = bis.read(buf);
             if (c == EOF)
                 break;

             baos.write(buf, 0, c);
         }

         conn.disconnect();
         is.close();

         byte[] b = baos.toByteArray();
         baos.flush();

         return b;
     }

 }