[SWIFT] Address to the problem that the video is paused during background transition while playing video on iOS14

Correspondence

• playerView.player = nil
• playerView.player = player

** Change the execution timing of **

@objc func applicationWillResignActive(_ notification: NSNotification?) {
   playerView.player = nil
}

@objc func applicationDidBecomeActive(_ notification: NSNotification?) {
   playerView.player = player
}

Background

• User "Background playback is strange after updating to iOS14. Somehow: rage :: bangbang:"
• Watakushi ": sob:"

Before correspondence

• ʻApplicationDidEnterBackground was playerView.player = nil` * According to the contents of the document published by Apple

Survey

• It stopped working even though I didn't do anything ⇒ OS specifications have changed?
• Pause when going to the background ⇒ Is it the same as the operation with the player set in the layer?

Verification

1. Manually playerView.player = nil during video playback and before background migration
2. Go to background

⇒ ** "Playback continued!" **

The conclusion drawn is ... ** "Isn't the timing of checking if there is a player in the layer changed?" **

Revalidation

1. Changed to playerView.player = nil in ** ʻapplicationWillResignActive ** that runs before ʻapplicationDidEnterBackground
2. ʻapplicationWillResignActive is paired with ** ʻapplicationDidBecomeActive **, so change to playerView.player = player.

⇒ ** "Playback continued!" **

• We have also confirmed that it works on iOS 11-14 and iPad OS 13 and 14.

Summary

• Even if you write it as Apple's document, it will not work, so there is a high possibility of an OS malfunction.
• It is rumored that this bug has been fixed in iOS 14.2 beta2.

Other

• It's been a while since iOS14 was released, but I haven't seen this solution, so I'll post an article.

References

1. Apple : Playing media while in the background using AV Foundation on iOS
2. Apple : Playing Audio from a Video Asset in the Background
3. @KenNagami: iOS App Lifecycle
4. @bosteri_bon: Fixed the problem that "background playback" is not possible on iOS14