AvFoundation framework, AvPlayer pause method causes a crash after app minimized - swift

Question

I am showing mp4 video file in the background with UIView component and AVFoundation framework.
But it gives an error after app is minimized by app user. Because player.pause() method causes a crash as you see. Here is the error: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
import UIKit
import AVFoundation
import AVKit
class ViewController: UIViewController {
private var player: AVPlayer!
#IBOutlet weak var videoUiViewOutlet: UIView!
override func viewDidLoad() {
super.viewDidLoad()
self.setupView()
}
private func setupView()
{
let path = URL(fileURLWithPath: Bundle.main.path(forResource: "clouds", ofType: "mp4")!)
let player = AVPlayer(url: path)
let newLayer = AVPlayerLayer(player: player)
newLayer.frame = self.videoUiViewOutlet.frame
self.videoUiViewOutlet.layer.addSublayer(newLayer)
newLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
player.play()
player.actionAtItemEnd = AVPlayer.ActionAtItemEnd.none
NotificationCenter.default.addObserver(self, selector: #selector(self.videoDidPlayToEnd(notification:)),
name: NSNotification.Name(rawValue: "AVPlayerItemDidPlayToEndTimeNotification"), object: player.currentItem)
NotificationCenter.default.addObserver(self, selector: #selector(enteredBackground), name: UIApplication.didEnterBackgroundNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(enteredForeground), name: UIApplication.willEnterForegroundNotification, object: nil)
}
#objc func videoDidPlayToEnd(notification: Notification)
{
let player: AVPlayerItem = notification.object as! AVPlayerItem
player.seek(to: .zero, completionHandler: nil)
}
#objc func enteredBackground() {
print("scope: enteredBackground")
player.pause()
}
#objc func enteredForeground() {
print("scope: enteredForeground")
player.play()
}
}
How can I solve this problem? Video should pause after app is minimized. And video should continue after app is maximized.

Answer 1

The issue is because you haven't assigned the value to player property of the class ViewController, i.e.
private var player: AVPlayer!
And since it is a forced unwrap optional, it'll have nil as its default value. And using it in enteredBackground() method will result in runtime exception.
Solution:
In setupView() method, replace
let player = AVPlayer(url: path)
with
self.player = AVPlayer(url: path)