new URL("http://www.qiushibaike.com/"                

                + "pic/"                

                + "app115736045.jpg");           

                //打开该URL对应的资源输入流           

                 InputStream is = url.openStream(); 

                  //从inputStream解析图片 

                   bitmap = BitmapFactory.decodeStream(is); 

用这种方式为什么无法下载图片，老是提示SkImageDecoder::Factory returned null或者java.io.FileNotFoundException: http://m.mm131.com/xinggan/m.jpg，访问网络的权限已经写了