Help enabling downloads through webview (Kotlin)

[Maximiliano Corbo]

Good day. I'm new to android development and I'm trying to develop a simple webview application, picked a nice template and went through the steps and made good progress, I managed to load my site fully and enable javascript, that works as intended, however I'm not able to make the app download anything, I host a few pdf files that should open or download through it, but nothing happens.

I looked at a few answers here and it is to my understanding that I need to specifically add a function for that, could you give me a hand? I have tried multiple different code and tweaking them, but I wasn't able to get it to work, here is my base code:

package com.logista.test.ui.home

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.webkit.WebResourceRequest
import android.webkit.WebView
import android.webkit.WebViewClient
import android.app.DownloadManager
import androidx.fragment.app.Fragment
import androidx.lifecycle.ViewModelProvider
import com.logista.test.R


class HomeFragment : Fragment() {

    private lateinit var homeViewModel: HomeViewModel

    override fun onCreateView(
            inflater: LayoutInflater,
            container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        homeViewModel =
                ViewModelProvider(this).get(HomeViewModel::class.java)
        val root = inflater.inflate(R.layout.fragment_home, container, false)
        val myWebView: WebView = root.findViewById(R.id.webview)
        myWebView.webViewClient = WebViewClient()
        myWebView.settings.javaScriptEnabled = true
        myWebView.loadUrl("https://www.example.org/")
        return root
    }
}

I believe I should be adding

import android.app.DownloadManager

And tweak this

        // Set web view download listener

        web_view.setDownloadListener(DownloadListener {
            url,
            userAgent,
            contentDescription,
            mimetype,
            contentLength ->

            // Initialize download request
            val request = DownloadManager.Request(Uri.parse(url))

            // Get the cookie
            val cookies = CookieManager.getInstance().getCookie(url)

            // Add the download request header
            request.addRequestHeader("Cookie",cookies)
            request.addRequestHeader("User-Agent",userAgent)

            // Set download request description
            request.setDescription("Downloading requested file....")

            // Set download request mime tytpe
            request.setMimeType(mimetype)

            // Allow scanning
            request.allowScanningByMediaScanner()

            // Download request notification setting
            request.setNotificationVisibility(
                    DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)

            // Guess the file name
            val fileName = URLUtil.guessFileName(url, contentDescription, mimetype)

            // Set a destination storage for downloaded file
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)

            // Set request title
            request.setTitle(URLUtil.guessFileName(url, contentDescription, mimetype));


            // DownloadManager request more settings
            request.setAllowedOverMetered(true)
            request.setAllowedOverRoaming(false)
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                request.setRequiresCharging(false)
                request.setRequiresDeviceIdle(false)
            }
            request.setVisibleInDownloadsUi(true)


            // Get the system download service
            val dManager = getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager

            // Finally, request the download to system download service
            dManager.enqueue(request)
        })


        // Load button click listener
        button_load.setOnClickListener{
            // Load url in a web view
            web_view.loadUrl(url)
        }

    }

Taken from here: https://android--code.blogspot.com/2018/03/android-kotlin-webview-file-download.html

I did the basics, renaming the function accordingly and such, but it gives me quite a few errors when building the app, for instance uri isn't defined, cookiemanager isn't defined, environment isn't defined, build isn't defined, and such, could you give me some guidance?