如何从parcelFileDescriptor访问fileDescriptor

Question

我正在尝试从我的PDFRenderer项目中的parcelFileDescriptor ....中获取fileDescriptor。 任何人都可以帮我解决..我被困了。以下是PDFRenderer片段正在进行中..

private void render() throws FileNotFoundException, IOException {
    // TODO Auto-generated method stub

    imageView = (ImageView) findViewById(R.id.imageView);
    REQ_WIDTH = imageView.getWidth();
    REQ_HEIGHT = imageView.getHeight();
    Bitmap bitmap = Bitmap.createBitmap(REQ_WIDTH, REQ_HEIGHT, Bitmap.Config.ARGB_4444);

    try {           
        String aDataRow = "";   
        String aBuffer = "";  
        File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/sample.pdf");            
        if(file.exists())
        {
            FileInputStream fIn=new FileInputStream(file);
            setmFileDescriptor(fIn.getFD());

            if(this.mFileDescriptor.valid())
            {
                 ParcelFileDescriptor pfdesc=mFileDescriptor;

                //stuck here....
                 PdfRenderer renderer = new PdfRenderer(pfdesc);
                 final int pageCount = renderer.getPageCount();   
                 if (currentPage < 0) 
                 {
                        currentPage = 0;
                 } else if (currentPage >= renderer.getPageCount()) {
                        currentPage = renderer.getPageCount() - 1;
                 }

                 Matrix m = imageView.getImageMatrix();
                 Rect rect = new Rect(0, 0, REQ_WIDTH, REQ_HEIGHT);
                 renderer.openPage(currentPage).render(bitmap, rect, m, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);
                 if(m!=null)
                 {
                    imageView.setImageMatrix(m);
                    imageView.setImageBitmap(bitmap);
                    imageView.invalidate();
                    renderer.close();
                 }
            }
      }