<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!--PDF Viewer to display our PDF-->
    <com.github.barteksc.pdfviewer.PDFView
        android:id="@+id/idPDFView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

import android.os.AsyncTask;
import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;

import com.github.barteksc.pdfviewer.PDFView;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.net.ssl.HttpsURLConnection;

public class MainActivity extends AppCompatActivity {

    // creating a variable
    // for PDF view.
    PDFView pdfView;

    // url of our PDF file.
    String pdfurl = "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // initializing our pdf view.
        pdfView = findViewById(R.id.idPDFView);
        new RetrivePDFfromUrl().execute(pdfurl);
    }

    // create an async task class for loading pdf file from URL.
    class RetrivePDFfromUrl extends AsyncTask<String, Void, InputStream> {
        @Override
        protected InputStream doInBackground(String... strings) {
            // we are using inputstream 
            // for getting out PDF.
            InputStream inputStream = null;
            try {
                URL url = new URL(strings[0]);
                // below is the step where we are 
                // creating our connection.
                HttpURLConnection urlConnection = (HttpsURLConnection) url.openConnection();
                if (urlConnection.getResponseCode() == 200) {
                    // response is success.
                    // we are getting input stream from url 
                    // and storing it in our variable.
                    inputStream = new BufferedInputStream(urlConnection.getInputStream());
                }

            } catch (IOException e) {
                // this is the method 
                // to handle errors.
                e.printStackTrace();
                return null;
            }
            return inputStream;
        }

        @Override
        protected void onPostExecute(InputStream inputStream) {
            // after the execution of our async 
            // task we are loading our pdf in our pdf view.
            pdfView.fromStream(inputStream).load();
        }
    }
}