pdf intent.java

File sd = new File(Environment.getExternalStorageDirectory() + File.separator + PDFFolder + File.separator + model.get(idx));
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.fromFile(sd));
intent.setDataAndType(Uri.fromFile(sd), "application/pdf");
try {
    getContext().startActivity(intent);
}catch(ActivityNotFoundException e){
    //Show a message that PDF viewer is not installed
}