缓存网络图片 以及流接受图片

1. 保存在sdcard 首先不要忘记权限

//First create a new URL object  
URL url = new URL("http://www.google.co.uk/logos/holiday09_2.gif") 
 
//Next create a file, the example below will save to the SDCARD using JPEG format 
File file = new File("/sdcard/example.jpg"); 
 
//Next create a Bitmap object and download the image to bitmap 
Bitmap bitmap = BitmapFactory.decodeStream(url.openStream()); 
 
//Finally compress the bitmap, saving to the file previously created 
bitmap.compress(CompressFormat.JPEG, 100, new FileOutputStream(file));

2.使用Collection(HashMap,List etc.)  你必须使用java.lang.ref.SoftReference specifically 如果你的图片很大

HashMap<String,SoftReference<Bitmap>> imageCache = 
        new HashMap<String,SoftReference<Bitmap>>();