How can I add alert message using alertcontroller? - ios

Question

I am working on an open source application using Xcode 9.3.1 Swift 4.
There is a play button. When the user clicks on the play button the audio file downloads automatically before it starts playing. I want to add an alert message that alerts the user, shows the file size, and lets him accept or not to proceed with the download.
Here my audiobarview.xib code:
import GenericDataSources
import QueuePlayer
import UIKit
internal protocol AdvancedAudioOptionsViewControllerDelegate : AnyObject {
internal func advancedAudioOptionsViewController(_ controller: AdvancedAudioOptionsViewController, finishedWith options: AdvancedAudioOptions)
}
internal class AdvancedAudioOptionsViewController : UIViewController, UIGestureRecognizerDelegate {
weak internal var delegate: AdvancedAudioOptionsViewControllerDelegate?
#IBOutlet weak internal var tableView: UITableView!
#IBOutlet weak internal var contentView: UIView!
#IBOutlet weak internal var bottomConstraint: NSLayoutConstraint!
#IBOutlet weak internal var navigationBar: UINavigationBar!
lazy internal var playButton: UIButton { get set }
internal init(options: AdvancedAudioOptions)
required internal init?(coder aDecoder: NSCoder)
override internal func viewDidLoad()
override internal func viewDidAppear(_ animated: Bool)
override internal func viewDidLayoutSubviews()
#IBAction internal func playButtonTapped(_ sender: Any)
#IBAction internal func dismissView(_ sender: Any)
internal func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool
}
extension UIView {
internal func round(corners: UIRectCorner, radius: CGFloat)
}
Here is the audiofilesdownloader.swift code:
import BatchDownloader
import PromiseKit
class AudioFilesDownloader {
let audioFileList: QariAudioFileListRetrieval
let downloader: DownloadManager
let ayahDownloader: AnyInteractor<AyahsAudioDownloadRequest, DownloadBatchResponse>
private var response: DownloadBatchResponse?
init(audioFileList: QariAudioFileListRetrieval,
downloader: DownloadManager,
ayahDownloader: AnyInteractor<AyahsAudioDownloadRequest, DownloadBatchResponse>) {
self.audioFileList = audioFileList
self.downloader = downloader
self.ayahDownloader = ayahDownloader
}
func cancel() {
response?.cancel()
response = nil
}
func needsToDownloadFiles(qari: Qari, range: VerseRange) -> Bool {
let files = filesForQari(qari, range: range)
return !files.filter { !FileManager.documentsURL.appendingPathComponent($0.destinationPath).isReachable }.isEmpty
}
func getCurrentDownloadResponse() -> Promise<DownloadBatchResponse?> {
if let response = response {
return Promise(value: response)
} else {
return downloader.getOnGoingDownloads().then { batches -> DownloadBatchResponse? in
let downloading = batches.first { $0.isAudio }
self.createRequestWithDownloads(downloading)
return self.response
}
}
}
func download(qari: Qari, range: VerseRange) -> Promise<DownloadBatchResponse?> {
return ayahDownloader
.execute(AyahsAudioDownloadRequest(range: range, qari: qari))
.then(on: .main) { responses -> DownloadBatchResponse? in
// wrap the requests
self.createRequestWithDownloads(responses)
return self.response
}
}
private func createRequestWithDownloads(_ batch: DownloadBatchResponse?) {
guard let batch = batch else { return }
response = batch
response?.promise.always { [weak self] in
self?.response = nil
}
}
func filesForQari(_ qari: Qari, range: VerseRange) -> [DownloadRequest] {
return audioFileList.get(for: qari, range: range).map {
DownloadRequest(url: $0.remote, resumePath: $0.local.stringByAppendingPath(Files.downloadResumeDataExtension), destinationPath: $0.local)
}
}
}

Answer 1

Assuming you have the filesize as a variable filesize
Swift 4:
let alert = UIAlertController(title: "Proceed with download?", message: "File size: \(filesize)", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: {(alert: UIAlertAction!) in
// Leave empty, dismisses the alert
}))
alert.addAction(UIAlertAction(title: "Download Song", style: .default, handler: {(alert: UIAlertAction!) in
// Code to download song
}))
self.present(alert, animated: true, completion: nil)