使用zxing扫描sd卡中的二维码不能在Android中运行

Question

    String imageInSD = Environment.getExternalStorageDirectory().getAbsolutePath()+"temp.jpg";
    Bitmap photoTmp = BitmapFactory.decodeFile(imageInSD);
    LuminanceSource source = new RGBLuminanceSource(photoTmp);
    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
    Reader reader = new MultiFormatReader();
    Result result = reader.decode(bitmap);

这是我的代码..但它不是扫描图像..但是当我捕获相同的图像并扫描它时...