图片异步加载框架（框架）

参考自http://blog.csdn.net/hantangsongming/article/details/41961749 博客

创建继承自Application的类用于在程序最开始初始化图片缓存加载参数
public class UILApplication extends Application {  
  
    @Override  
    public void onCreate() {  
        super.onCreate();  
        initImageLoader(getApplicationContext());  
    }  
  
    public static void initImageLoader(Context context) {  
        //缓存文件的目录  
        File cacheDir = StorageUtils.getOwnCacheDirectory(context, "universalimageloader/Cache");   
        ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(context)  
                .memoryCacheExtraOptions(480, 800) // max width, max height，即保存的每个缓存文件的最大长宽   
                .threadPoolSize(3) //线程池内线程的数量  
                .threadPriority(Thread.NORM_PRIORITY - 2)  
                .denyCacheImageMultipleSizesInMemory()  
                .diskCacheFileNameGenerator(new Md5FileNameGenerator()) //将保存的时候的URI名称用MD5 加密  
                .memoryCache(new UsingFreqLimitedMemoryCache(2 * 1024 * 1024))  
                .memoryCacheSize(2 * 1024 * 1024) // 内存缓存的最大值  
                .diskCacheSize(50 * 1024 * 1024)  // SD卡缓存的最大值  
                .tasksProcessingOrder(QueueProcessingType.LIFO)  
                // 由原先的discCache -> diskCache  
                .diskCache(new UnlimitedDiskCache(cacheDir))//自定义缓存路径    
                .imageDownloader(new BaseImageDownloader(context, 5 * 1000, 30 * 1000)) // connectTimeout (5 s), readTimeout (30 s)超时时间    
                .writeDebugLogs() // Remove for release app  
                .build();  
        
        //全局初始化此配置    
        ImageLoader.getInstance().init(config);  
    }  
}  
然后创建类Constants 用来获取测试使用的图片url地址
public final class Constants {

    public static final String[] IMAGES = new String[] {
            // Heavy images
            "http://avatar.csdn.net/F/E/4/1_gengkunpeng.jpg",
            "http://p0.so.qhimg.com/bdr/_240_/t012f2ffd5f9de0538a.jpg",
            "http://p0.so.qhimg.com/bdr/_240_/t0120bd8cb3b4a3e6c5.jpg",
            "http://p0.so.qhimg.com/bdr/_240_/t0101bc29746f8aca3f.jpg",
            "http://p2.so.qhimg.com/bdr/_240_/t0143bb6f176386979c.jpg",
            // Light images
            "http://tabletpcssource.com/wp-content/uploads/2011/05/android-logo.png",
            "http://4.bp.blogspot.com/-LEvwF87bbyU/Uicaskm-g6I/AAAAAAAAZ2c/V-WZZAvFg5I/s800/Pesto+Guacamole+500w+0268.jpg", // Image with "Mark has been invalidated" problem
            "file:///sdcard/Universal Image Loader @#&=+-_.,!()~'%20.png", // Image from SD card with encoded symbols
            "assets://Living Things @#&=+-_.,!()~'%20.jpg", // Image from assets
            "drawable://" + R.drawable.ic_launcher, // Image from drawables
            "http://upload.wikimedia.org/wikipedia/ru/b/b6/袣邪泻_泻芯褌_褋_屑褘褕邪屑懈_胁芯械胁邪谢.png", // Link with UTF-8
            "https://www.eff.org/sites/default/files/chrome150_0.jpg", // Image from HTTPS
            "http://bit.ly/soBiXr", // Redirect link
            "http://img001.us.expono.com/100001/100001-1bc30-2d736f_m.jpg", // EXIF
            "", // Empty link
            "http://wrong.site.com/corruptedLink", // Wrong link
    };
}
在mainactivity中
public class MainActivity extends Activity {  
    private ImageLoader imageLoader;  
    private ListView lv;  
    private String[] imageUrls;  
    private DisplayImageOptions options;  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        imageLoader = ImageLoader.getInstance();  
        lv = (ListView)findViewById(R.id.list);  
          
        imageUrls = com.example.loadimage.Constants.IMAGES;  
        
        // 使用DisplayImageOptions.Builder()创建DisplayImageOptions  
        options = new DisplayImageOptions.Builder()  
                .showImageOnLoading(R.drawable.ic_stub) // 设置图片下载期间显示的图片  
                .showImageForEmptyUri(R.drawable.ic_empty) // 设置图片Uri为空或是错误的时候显示的图片  
                .showImageOnFail(R.drawable.ic_error) // 设置图片加载或解码过程中发生错误显示的图片  
                .cacheInMemory(true) // 设置下载的图片是否缓存在内存中  
                .cacheOnDisk(true) // 设置下载的图片是否缓存在SD卡中  
                .displayer(new RoundedBitmapDisplayer(20)) // 设置成圆角图片  
                .build(); // 构建完成  
        lv.setAdapter(new ItemListAdapter());  
    }  
  
    @Override  
    public boolean onCreateOptionsMenu(Menu menu) {  
        // Inflate the menu; this adds items to the action bar if it is present.  
        getMenuInflater().inflate(R.menu.main_menu, menu);  
        return true;  
    }  
  
    @Override  
    public boolean onOptionsItemSelected(MenuItem item) {  
        switch (item.getItemId()) {  
            case R.id.item_clear_memory_cache:  
                ImageLoader.getInstance().clearMemoryCache();  
                return true;  
            case R.id.item_clear_disc_cache:  
                ImageLoader.getInstance().clearDiskCache();  
                return true;  
            default:  
                return false;  
        }  
    }  
  
    class ItemListAdapter extends BaseAdapter {  
        @Override  
        public int getCount() {  
            // TODO Auto-generated method stub  
            return imageUrls.length;  
        }  
  
        @Override  
        public Object getItem(int position) {  
            // TODO Auto-generated method stub  
            return imageUrls[position];  
        }  
  
        @Override  
        public View getView(int position, View convertView, ViewGroup parent) {  
            // TODO Auto-generated method stub  
            ViewHolder holder = null;  
            if (convertView == null) {  
                convertView = getLayoutInflater().inflate(R.layout.item_list, parent, false);  
                holder = new ViewHolder();  
                holder.text = (TextView) convertView.findViewById(R.id.text);  
                holder.image = (ImageView) convertView.findViewById(R.id.image);  
                convertView.setTag(holder);  
            } else {  
                holder = (ViewHolder) convertView.getTag();  
            }  
            holder.text.setText("Item " + (position + 1));  
            imageLoader.displayImage(imageUrls[position], holder.image, options);  
            return convertView;  
        }  
  
        @Override  
        public long getItemId(int position) {  
            // TODO Auto-generated method stub  
            return position;  
        }  
  
        class ViewHolder {  
            public ImageView image;  
            public TextView text;  
        }  
    }  
  
}  

所需要的jar包以及demo包：http://note.youdao.com/yws/public/redirect/share?id=9ea396c3ed0cd53a9602b607caeccfe2&type=false