关于BitmapFactory.decodeStream(is)方法无法正常解码为Bitmap对象的解决方法

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.   

注意黑体字。以下是具体代码：

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();        
    }