Equivalent path to http://localhost:8100/assets/ for ionic android

Hello code lovers,

I have problem on my web app ( ionic 4, angular 6 and cordova 9).

I have to open a PDF file which located in src/assets folder,
while running locally filePath = 'http://localhost:8100/assets/ is working fine, but on android build it’s failed to locate assets path.

on opening of app , it shows
Application Error
The connection to the server was unsuccessful.

I know app does not run on localhost:port/

waiting for solution.