How to pass IBOutlet between two classes?

Question

I have a class for managing AVPlayer and ViewController showing AVPlayer. In ViewController I have 3 IBOutlets:

@IBOutlet weak var playButton: UIButton!
@IBOutlet weak var progressBar: UIProgressView!
@IBOutlet weak var timerLabel: UILabel!

The problem is I can't figure out how to pass IBOutlets from ViewController to my player managing class. I always get nil and

fatal error: unexpectedly found nil while unwrapping an Optional value

when initialising progressBar, timerLabel or playButton.

Here is some code from my player managing class:

import UIKit
import AVFoundation

class RecordsAudioPlayer: NSObject
{
    var player = AVPlayer()
    var timerUpdateAudioProgressView = Timer()
    var timerUpdateTime = Timer()
    var isPlaying: Bool = false

...

func updateAudioProgressView()
    {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let vc = storyboard.instantiateViewController(withIdentifier: "callRecords") as! CallRecordsViewController

        let progressBar = vc.progressBar! 
        print("method fired: updateAudioProgressView ", NSDate.init(timeIntervalSinceNow: 0).description)
        if isPlaying
        {
            let currentPlayerItem = player.currentItem
            let duration = Float((currentPlayerItem?.asset.duration.value)!)/Float((currentPlayerItem?.asset.duration.timescale)!)
            let currentTime = Float(player.currentTime().value)/Float(player.currentTime().timescale)
            progressBar.setProgress(Float(currentTime/duration), animated: false)
        }
    }

    func updateTime()
    {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let vc = storyboard.instantiateViewController(withIdentifier: "callRecords") as! CallRecordsViewController
        let timerLabel: UILabel! = vc.timerLabel! //***I get exception here
        print("method fired: updateTime ", NSDate.init(timeIntervalSinceNow: 0).description)
        let currentTime = Int64(player.currentTime().value)/Int64(player.currentTime().timescale)
        let minutes = currentTime / 60
        let seconds = currentTime - minutes * 60
        timerLabel.text = String(format: "%02d : %02d", Int(minutes), Int(seconds))
    }

Answer 1

In this case delegates came for our rescue. Create delegate methods for your RecordsAudioPlayer class. And use them to update progress bar and timer label.

protocol RecordsAudioPlayerDelegate
{
  func audioplayerProgressUpdated(time:CGFloat) // change the method as your wish
}

class RecordsAudioPlayer: NSObject
{
  var delegate:RecordsAudioPlayerDelegate?
  var player = AVPlayer()
  var timerUpdateAudioProgressView = Timer()
  var timerUpdateTime = Timer()
  var isPlaying: Bool = false
    ...
    ...
    ...

  //Call the delegate method from where you get the player current time
  self.delegate.audioplayerProgressUpdated(playerTime)

  //For controlling play/pause using play button 
  func playButtonClicked()
  {
    //play/pause player based on player status
  }
}

And inside your ViewController while/after creating RecordsAudioPlayer object set delegate as self

class YourViewController : UIViewController, RecordsAudioPlayerDelegate
{
  var recordsAudioPlayer : RecordsAudioPlayer!

  // set delegate where you create object for RecordsAudioPlayer
  self.recordsAudioPlayer.delegate = self

  //Now implement the delegate function
  func audioplayerProgressUpdated(time:CGFloat)
  {
   //update progress view and timer label
  }

  //And inside from the play button action method 
  @IBAction func playButtonClicked(sender: UIButton)
  {
   self.recordsAudioPlayer.playButtonClicked()
  }

}