Как реализовать преобразование текста в речь в PDF-файле, который уже загружен в pdfview

I'm trying to implement a text to speech in my application. First, I have implemented PDFview that allows me to pick PDF files from my device and load it. What I want to achieve is that after loading this PDF to the PDFview, I want to read the text out. How do I achieve this?

using same Uri passed into my PDFView libabry to load the pdf so i can view it

public String getRealPathFromURI(Context context, Uri contentURI)
    {
        String result;

        Cursor cursor = context.getContentResolver().query(uri, null, null, null, null);
        if(cursor == null)
        {
            result = contentURI.getPath();
        } else {

            cursor.moveToFirst();
            int idx = cursor.getColumnIndex(MediaStore.Files.FileColumns.DATA);
            result = cursor.getString(idx);
            cursor.close();
        }
        return result;
}








 btnSpeak.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View view) {
                    String parsedText = "";
               try
               {

                    PdfReader pdfReader = new  PdfReader(getRealPathFromURI(getContext(), uri));
                   int n = pdfReader.getNumberOfPages();
                  for (int i = 0; i < n; i++) {
                       parsedText = parsedText + PdfTextExtractor.getTextFromPage(pdfReader, i + 1).trim() + "\n";
                   }
                   pdfReader.close();


                   textToSpeech.speak(parsedText, TextToSpeech.QUEUE_FLUSH, null);
               }
               catch (Exception ex)
               {

               }
           }
       });