How to update a progress view that is on another UIViewController - SWIFT? - ios

Question

I have a UITableViewController that is embedded in a UINavigationController. When I click on a row I am attempting to upload a file. To show the progress of this upload I have decided to use custom popup (another UIViewController) - if anyone has a better idea to show the progress of the upload in this context I am open to it.
The only idea I have to transfer continuous data from one UIViewController to another (if that is possible) is by using a Singleton. My code is below, my issue at the moment is I do not know how to update the progress view even though now it has access to the progress data via the singleton.
class SharedSingleton{
private init(){}
static let shared = SharedSingleton()
var prog: Float = 0
}
UITableViewController:
Using Alamofire to get the fraction of upload completed:
/**TRACK PROGRESS OF UPLOAD**/
upload.uploadProgress { progress in
//print(progress.fractionCompleted)
let mySingleton = SharedSingleton.shared
mySingleton.prog = Float(progress.fractionCompleted)
print("mySingleton.prog: \(mySingleton.prog)")
UIViewController containing popup:
#IBOutlet weak var popUpContainer: UIView!
#IBOutlet weak var uploadStatus: UILabel!
#IBOutlet weak var progressBar: UIProgressView!
override func viewDidLoad() {
super.viewDidLoad()
// Make popup have rounded corners
popUpContainer.layer.cornerRadius = 5
popUpContainer.layer.masksToBounds = true
// Call Singleton and assign progress of upload to progress view
// HOW TO UPDATE ??????
let mySingleton = SharedSingleton.shared
progressBar.progress = mySingleton.prog
}

Answer 1

One option would be to use NotificationCenter and in your pop-up view controller subscribe to notifications and in your API callback for the progress, publish a notification.
For example:
UploadNotifications.swift:
import Foundation
extension Notification.Name {
static let UploadProgress = Notification.Name("UploadProgress")
}
UploadProgressViewController.swift (your pop-up):
import UIKit
class UploadProgressViewController: UIViewController {
#IBOutlet weak var progressBar: UIProgressView!
private let progress: Progress = {
let progress = Progress()
progress.completedUnitCount = 0
progress.totalUnitCount = 100
return progress
}()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
NotificationCenter.default.addObserver(self, selector: #selector(self.uploadDidProgress(_:)), name: .UploadProgress, object: nil)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(self)
}
#objc private func uploadDidProgress(_ notification: Notification) {
if let progress = notification.object as? Int64 {
self.progress.completedUnitCount = progress
if progress == 100 {
// dismiss/exit
}
}
}
}
Then in your method with the upload progress callback:
upload.uploadProgress { progress in
NotificationCenter.default.post(name: .SyncDidProgress, object: Int64(progress))
}