How do I make pdfview to choose any file from external storage and then display it

I have been trying to work with PDFview library in Android studio. I have implemented the from asset and it's working perfectly. But what I want to do is try to pick any PDF file on my device and then view it in the app. According to what I have gathered,

After selecting a PDF file from my device, I get a blank screen. I have Search for examples on this but couldn't find

File file = new File(Environment.getExternalStorageDirectory().toString()); pdfView.fomFile(file).load();