關於BitmapFactory.decodeStream(is)方法無法正常解碼為Bitmap對象的解決方法

在android sdk 1.6版本API幫助文檔中，其中關於BitmapFactory.decodeFactory.decodeStream(InputStream is)的幫助文檔是這么說明的：

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.   

注意黑體字。以下是具體代碼：

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;  
  
}  

后來調試發現，result為null，加之查看幫助文檔中的黑體字，
所以在所獲得的InputStream不為空的情況下，調用BitmapFactory.decodeStream(is)方法，他也有可能無法解碼成bitmap,剛開始我懷疑是本身圖片地址有問題，或圖片自身格式不正確，但通過瀏覽器查看，圖片顯示正常，而且，我是保存了幾十張圖片，但每次都會有個別幾張圖片無法正常顯示，需要重復下載三四次，才可能保存成功。

后來在一篇文章中才發現，原來這是Android 1.6版本的一個bug！

有牛人提出的一個解決辦法，我試了試，問題解決了

首先在原方法中改一句：

result = BitmapFactory.decodeStream(new PatchInputStream(input));  

再創建一個類：

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;  
        }  
          
    }  

第二種方法：最終用的是這種方法

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();  
}  

/* 
     * 得到圖片字節流 數組大小 
     * */  
    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();        
    }