在android sdk 1.6版本API帮助文档中，其中关于BitmapFactory.decodeFactory.decodeStream(InputStream is)的帮助文档是这么说明的：
Bitmap android.graphics.BitmapFactory.decodeStream(InputStream is) public static Bitmap decodeStream (InputStream is) Since: API Level 1 Decode an input stream into a bitmap. <strong>If the input stream is null, or cannot be used to decode a bitmap, the function returns null</strong>. The stream's position will be where ever it was after the encoded data was read. Parameters is The input stream that holds the raw data to be decoded into a bitmap. Returns The decoded bitmap, or null if the image data could not be decoded.
public static Bitmap bmpFromURL(URL imageURL){ Bitmap result = null; try { HttpURLConnection connection = (HttpURLConnection)imageURL .openConnection(); connection.setDoInput(true); connection.connect(); InputStream input = connection.getInputStream(); result = BitmapFactory.decodeStream(input); } catch (IOException e) { e.printStackTrace(); } return result; }
后来调试发现，result为null，加之查看帮助文档中的黑体字，
所以在所获得的InputStream不为空的情况下，调用BitmapFactory.decodeStream(is)方法，他也有可能无法解码成bitmap,刚开始我怀疑是本身图片地址有问题，或图片自身格式不正确，但通过浏览器查看，图片显示正常，而且，我是保存了几十张图片，但每次都会有个别几张图片无法正常显示，需要重复下载三四次，才可能保存成功。
后来在一篇文章中才发现，原来这是android 1.6版本的一个bug！
有牛人提出的一个解决办法，我试了试，问题解决了
首先在原方法中改一句：
result = BitmapFactory.decodeStream(new PatchInputStream(input));
再创建一个类：
public class PatchInputStream extends FilterInputStream{ protected PatchInputStream(InputStream in) { super(in); // TODO Auto-generated constructor stub } public long skip(long n)throws IOException{ long m=0l; while(m<n){ long _m=in.skip(n-m); if(_m==0l){ break; } m+=_m; } return m; } }
第二种方法：最终用的是这种方法
InputStream is = httpConn.getInputStream();
if (is == null){
throw new RuntimeException("stream is null");
}else{
try {
byte[] data=readStream(is);
if(data!=null){
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
}
} catch (Exception e) {
e.printStackTrace();
}
is.close();
}
/* * 得到图片字节流 数组大小 * */ public static byte[] readStream(InputStream inStream) throws Exception{ ByteArrayOutputStream outStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while( (len=inStream.read(buffer)) != -1){ outStream.write(buffer, 0, len); } outStream.close(); inStream.close(); return outStream.toByteArray(); }
