Android输入流为jpeg文件的位图返回null

Question

当我从openhttpconnection获取一个获取jpeg文件url的输入流时，我总是得到一个返回null的位图。例如，我的网址字符串是

 http://10.0.2.2:8000/mydirectory/myfile.jpg

其中8000是使用模拟器运行的本地服务器的端口。我可以使用相同类型的URL来从web服务获取，但不能获取图像文件。有什么不同我要做一个jpgeg文件到位图或我的网址格式有什么问题吗？以下是我的代码。任何帮助表示赞赏。

  private Bitmap downloadImage(String url) {

        Bitmap bmap = null;
        InputStream inStream = null;

        try {
            inStream = openHttpConnection(url);
            Log.d("inStream", String.valueOf(inStream));
            bmap = BitmapFactory.decodeStream(inStream);
            if(inStream != null)
                inStream.close();

        }
        catch (IOException el) {
            el.printStackTrace();
        }
        return bmap;
    }

    private InputStream openHttpConnection(String urlString) throws IOException {

        InputStream inStream = null;
        int checkConn = -1;
        URL url = new URL(urlString);
        URLConnection conn = url.openConnection();
        try {

            HttpURLConnection httpConn = (HttpURLConnection) conn;
            httpConn.setAllowUserInteraction(false);
            httpConn.setInstanceFollowRedirects(true);
            httpConn.setRequestMethod("GET");
            httpConn.connect();
            checkConn = httpConn.getResponseCode();
            if (checkConn == HttpURLConnection.HTTP_OK) {
                inStream = httpConn.getInputStream();

            }

        }
        catch (Exception ex) {
            throw new IOException("Error connecting");
        }
        return inStream;
    }