1 package com.example.asyncloadpicture; 2  3 import java.util.ArrayList; 4  5 import android.app.Activity; 6 import android.content.Context; 7 import android.graphics.Bitmap; 8 import android.graphics.BitmapFactory; 9 import android.os.AsyncTask;10 import android.os.Bundle;11 import android.widget.GridView;12 13 /**14  * @author ymw15  * @data 2014-12-0316  */17 public class MainActivity extends Activity {18 19     private GridView gridViewImg;20     private ArrayList<ImageEntity> imageList = new ArrayList<ImageEntity>();21 22     @Override23     protected void onCreate(Bundle savedInstanceState) {24         super.onCreate(savedInstanceState);25         setContentView(R.layout.activity_main);26 27         gridViewImg = (GridView) findViewById(R.id.gridViewImg);28         initData();29     }30 31     private void initData() {32         for (int i = 0; i < 15; i++) {33             ImageEntity b = new ImageEntity();34             b.setImage(BitmapFactory.decodeResource(getResources(),35                     R.drawable.nopicture));36 37             imageList.add(b);38         }39 40         ImageAdapter adapter = new ImageAdapter(getApplicationContext(),41                 imageList);42         gridViewImg.setAdapter(adapter);43         String[] params = {44                 "http://images.cnitblog.com/i/169207/201408/112229149526951.png",45                 "p2" };46         new ImageLoadTask(getApplicationContext(), adapter).execute(params);47     }48 49     /** 图片异步加载类 */50     public class ImageLoadTask extends AsyncTask<String, Void, Void> {51         private ImageAdapter adapter;52 53         public ImageLoadTask(Context context, ImageAdapter adapter) {54             this.adapter = adapter;55         }56 57         @Override58         protected Void doInBackground(String... params) {59             String url = params[0];// 获取传来的参数，图片uri地址60             String p2 = params[1];61             for (int i = 0; i < adapter.getCount(); i++) {62                 ImageEntity bean = (ImageEntity) adapter.getItem(i);63                 Bitmap bitmap = BitmapFactory.decodeStream(Request64                         .HandlerData(url));65                 bean.setImage(bitmap);66                 publishProgress(); // 通知去更新UI67             }68 69             return null;70         }71 72         public void onProgressUpdate(Void... voids) {73             if (isCancelled())74                 return;75             // 更新UI76             adapter.notifyDataSetChanged();77         }78     }79 80     /** 图片实体 */81     public class ImageEntity {82         private Bitmap image;83 84         public Bitmap getImage() {85             return image;86         }87 88         public void setImage(Bitmap image) {89             this.image = image;90         }91 92     }93 }

 1 package com.example.asyncloadpicture; 2  3 import java.util.ArrayList; 4  5 import android.content.Context; 6 import android.view.LayoutInflater; 7 import android.view.View; 8 import android.view.ViewGroup; 9 import android.widget.BaseAdapter;10 import android.widget.ImageView;11 12 import com.example.asyncloadpicture.MainActivity.ImageEntity;13 14 /**15  * 16  * @author ymw17  * @data 2014-12-03 图片适配器18  */19 public class ImageAdapter extends BaseAdapter {20 21     private Context _context;22     private ArrayList<ImageEntity> _list;23 24     public ImageAdapter(Context context, ArrayList<ImageEntity> imageList) {25         this._context = context;26         this._list = imageList;27     }28 29     @Override30     public int getCount() {31         return _list.size();32     }33 34     @Override35     public Object getItem(int position) {36         return _list.get(position);37     }38 39     @Override40     public long getItemId(int position) {41         return position;42     }43 44     @Override45     public View getView(int position, View convertView, ViewGroup parent) {46         LayoutInflater inflater = LayoutInflater.from(_context);47         convertView = inflater.inflate(R.layout.gridview_item, null);48 49         ImageView imgView = (ImageView) convertView.findViewById(R.id.imgView);50         ImageEntity b = _list.get(position);51         // 如果有图片则读取，没有则跳过52         if (b.getImage() != null) {53             imgView.setImageBitmap(b.getImage());54         }55         return convertView;56     }57 }

 1 package com.example.asyncloadpicture; 2  3 import java.io.IOException; 4 import java.io.InputStream; 5 import java.net.URL; 6 import java.net.URLConnection; 7  8 import android.graphics.drawable.Drawable; 9 import android.util.Log;10 11 /**12  * 工具类，主要根据url读取图片返回流的方法13  * 14  * @author ymw15  * 16  */17 public class Request {18     public static InputStream HandlerData(String url) {19         InputStream inStream = null;20 21         try {22             URL feedUrl = new URL(url);23             URLConnection conn = feedUrl.openConnection();24             conn.setConnectTimeout(10 * 1000);25             inStream = conn.getInputStream();26         } catch (Exception e) {27             e.printStackTrace();28         }29 30         return inStream;31     }32 33     /** 直接返回Drawable对象设置图片 */34     public static Drawable loadImageFromNetwork(String imageUrl) {35         Drawable drawable = null;36         try {37             // 可以在这里通过文件名来判断，是否本地有此图片38             drawable = Drawable.createFromStream(39                     new URL(imageUrl).openStream(), "image.jpg");40         } catch (IOException e) {41             Log.d("test", e.getMessage());42         }43         if (drawable == null) {44             Log.d("test", "null drawable");45         } else {46             Log.d("test", "not null drawable");47         }48 49         return drawable;50     }51 }