Convert WebView to PDF in Android with Kotlin

package com.gtappdevelopers.kotlingfgproject

import android.content.Context
import android.os.Build
import android.os.Bundle
import android.print.PrintAttributes
import android.print.PrintJob
import android.print.PrintManager
import android.webkit.WebView
import android.webkit.WebViewClient
import android.widget.Button
import android.widget.Toast
import androidx.annotation.RequiresApi
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {
    // on below line we are creating variables for web view, 
    // button and print job as well as 
    // boolean variable for button pressed.
    lateinit var webView: WebView
    lateinit var savePDFBtn: Button
    lateinit var printJob: PrintJob

    // on below line we are initializing
    // button pressed variable as false
    var printBtnPressed = false

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        // initializing variables of web view and 
        // save button with their ids on below line.
        webView = findViewById(R.id.idWebView)
        savePDFBtn = findViewById(R.id.idBtnSavePDF)
        
        // on below line we are specifying 
        // url to load in our web view.
        webView.loadUrl("https://www.google.com")
        
        // on below line we are specifying web view client.
        webView.setWebViewClient(object : WebViewClient() {
            override fun onPageFinished(view: WebView, url: String) {
                super.onPageFinished(view, url)
                // initializing the webview Object on below line.
                webView = view
            }
        })
        // on below line we are adding click 
        // listener for our save pdf button.
        savePDFBtn.setOnClickListener {
            // on below line we are checking 
            // if web view is null or not.
            if (webView != null) {
                // if web view is not null we are calling 
                // print web page method to generate pdf.
                printWebPage(webView)
            } else {
                // in else condition we are simply displaying a toast message
                Toast.makeText(this, "Webpage not loaded..", Toast.LENGTH_SHORT).show()
            }
        }
    }

    // on below line we are creating a print 
    // web page method to print the web page.
    fun printWebPage(webview: WebView) {
        // on below line we are initializing 
        // print button pressed variable to true.
        printBtnPressed = true
        // on below line we are initializing 
        // our print manager variable.
        val printManager =
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
                this
                    .getSystemService(Context.PRINT_SERVICE) as PrintManager
            } else {
                TODO("VERSION.SDK_INT < KITKAT")
            }

        // on below line we are creating a variable for job name
        val jobName = " webpage" + webView.url
        // on below line we are initializing our print adapter.
        val printAdapter =
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
                // on below line we are creating 
                // our print document adapter.
                webView.createPrintDocumentAdapter(jobName)
            } else {
                TODO("VERSION.SDK_INT < LOLLIPOP")
            }
        // on below line we are checking id 
        // print manager is not null
        assert(printManager != null)
        
        // on below line we are initializing
        // our print job with print manager
        printJob = printManager.print(
            jobName, printAdapter,
            // on below line we are calling 
            // build method for print attributes.
            PrintAttributes.Builder().build()
        )
    }


    @RequiresApi(Build.VERSION_CODES.KITKAT)
    override fun onResume() {
        super.onResume()
        
        // on below line we are checking 
        // if print button is pressed.
        if (printBtnPressed) {
            // in this case we are simply checking
            // if the print job is completed.
            if (printJob.isCompleted) {
                // in this case we are simply displaying a completed toast message
                Toast.makeText(this, "Completed..", Toast.LENGTH_SHORT).show()
            }
            
            // below method is called if the print job has started.
            else if (printJob.isStarted) {
                Toast.makeText(this, "Started..", Toast.LENGTH_SHORT).show()
            }
            
            // below method is called if print job has blocked.
            else if (printJob.isBlocked) {
                Toast.makeText(this, "Blocked..", Toast.LENGTH_SHORT).show()
            }
            
            // below method is called if print job has cancelled.
            else if (printJob.isCancelled) {
                Toast.makeText(this, "Cancelled..", Toast.LENGTH_SHORT).show()
            }
            
            // below method is called is print job is failed.
            else if (printJob.isFailed) {
                Toast.makeText(this, "Failed..", Toast.LENGTH_SHORT).show()
            }
            
            // below method is called if print job is queued.
            else if (printJob.isQueued) {
                Toast.makeText(this, "Jon Queued..", Toast.LENGTH_SHORT).show()
            }
            
            // on below line we are simply initializing
            // our print button pressed as false
            printBtnPressed = false
        }
    }
}