预览帧不会将文件保存到磁盘android

Question

这是我的代码。我在android上运行它。三星S4手机。你能帮忙吗？谢谢。

        public void onPreviewFrame(byte[] data, Camera mCamera) {

        String root = Environment.getExternalStorageDirectory().toString();

          Random generator = new Random();
      int n = 10000;
      n = generator.nextInt(n);

      String fname = " " + n;


                Camera.Parameters parameters = mCamera.getParameters();
                Size size = parameters.getPreviewSize();
                YuvImage image = new YuvImage(data, parameters.getPreviewFormat(),
                        mPreviewSize.width, mPreviewSize.height, null);
                File file = new File(Environment.getExternalStorageDirectory()
                        .getPath() + fname + "out.jpg");
                FileOutputStream filecon = null;
                try {
                    filecon = new FileOutputStream(file);
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                image.compressToJpeg(
                        new Rect(0, 0, image.getWidth(),    image.getHeight()), 90,
                        filecon);

    }