使用Facebook Pop动画弹出视图时UIImageView动画终止，求排查建议

Hey there, I’ve run into similar edge cases with UI animations conflicting before, so let’s walk through some practical checks to figure out what’s going on here:

• Verify the UIImageView’s View Hierarchy & Visibility
  When your Pop animation triggers, it’s possible the UIImageView is being accidentally removed from the view hierarchy, marked as hidden, or covered by another view. Add quick debug logs in your Pop animation’s start/complete callbacks to check:

  print("ImageView superview: \(imageView.superview)")
  print("ImageView is hidden: \(imageView.isHidden)")
  

  If either value changes unexpectedly during the Pop animation, that’s a clear clue.

• Check for Pop Animation Property Conflicts
  Facebook Pop animations might modify properties of your root view (like transform, alpha, or bounds) that ripple down to child views. Try moving your animated UIImageView to a separate subview that’s not part of the root view being animated by Pop. If the animation stays running, the conflict is likely tied to the root view’s Pop animation affecting child view animations.

• Adjust the RunLoop Mode for UIImageView Animation
  UIImageView’s default animation runs in the default runloop mode, which can get paused when other high-priority animations (like Pop) take over. Force the animation to run in common modes to keep it active:

  imageView.startAnimating()
  RunLoop.current.add(imageView.layer, forMode: .common)
  

  This ensures the animation keeps ticking even when the runloop switches modes during Pop’s animations.

• Monitor Pop Animation Lifecycle & Restore UIImageView Animation
  Hook into Pop’s animation lifecycle callbacks (like POPAnimationDelegate methods) to check the UIImageView’s animation state. You can manually restart the animation if it gets paused:

  func popAnimationDidStart(_ anim: POPAnimation) {
      if !imageView.isAnimating {
          imageView.startAnimating()
      }
  }
  
  func popAnimationDidStop(_ anim: POPAnimation, finished: Bool) {
      if !imageView.isAnimating {
          imageView.startAnimating()
      }
  }
  

  This acts as a safety net to restart the animation if Pop’s process interrupts it.

• Isolate the Problem with a Test Scenario
  Temporarily replace the Pop animation with a standard UIKit presentation (like present(_:animated:completion:)) and see if the UIImageView animation still stops. If it works normally with UIKit’s default animation, the issue is definitely tied to how Pop interacts with the view hierarchy or runloop. If it still fails, you’ll need to look for other factors (like conflicting Auto Layout constraints or other concurrent animations).

• Inspect Pop Animation Type & Parameters
  Certain Pop animation types (like spring animations with high tension) might cause more aggressive view updates that interrupt child animations. Try switching to a basic POPBasicAnimation with a longer duration, or tweaking spring parameters, to see if the UIImageView animation stays intact.

内容的提问来源于stack exchange，提问作者FaceWaller