如何手动停止Lottie动画？解决XCode中Lottie后台运行及内存问题

Hey there, let's work through your Lottie animation issues one by one. I'll break down the problems in your current code and provide a fixed version with clear explanations.

1. Repeated AnimationView Initialization: Every time you tap the popup button, you create a new AnimationView instance and add it to the view, leaving old instances unremoved—this causes memory bloat over time.
2. Unmanaged Animation State: When navigating away from the view controller, the animation keeps running in the background, leading to unnecessary memory usage and unexpected restarts when you return.
3. No Controlled Stop Mechanism: There's no built-in logic to halt the animation after a specific duration.

Step 1: Reuse AnimationView Instead of Recreating It #

Instead of initializing a new AnimationView in the animation() method, use the existing popupView outlet you've already set up. This prevents memory leaks from orphaned animation instances.

Step 2: Manage Animation in View Lifecycle Methods #

Pause the animation when the view disappears, and clean up resources when the view controller is destroyed to stop background execution and free memory.

Step 3: Add Timed Stop Logic #

Use a delayed dispatch call to stop the animation after your desired duration (e.g., 3 seconds in the example below).

Here's the revised code:

import UIKit
import Lottie

class CoffeeSpecialFortunePageVC: UIViewController {
    @IBAction func PopUpIn(_ sender: Any) {
        animateIn(desiredView: PopupBlur)
        animateIn(desiredView: popupView)
        startAnimation()
    }
    
    @IBAction func SuccesBtn(_ sender: UIView) {
        stopAnimation()
        animateOut(desiredView: PopupBlur)
        animateOut(desiredView: popupView)
    }
    
    @IBOutlet var popupView: AnimationView!
    @IBOutlet var PopupBlur: UIVisualEffectView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.purple
        PopupBlur.bounds = self.view.bounds
        popupView.bounds = CGRect(x: 0, y: 0, width: self.view.bounds.width * 0.9, height: self.view.bounds.height * 0.4)
        
        // Initialize Lottie animation once on view load
        setupAnimation()
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        // Pause animation when leaving the view to stop background execution
        stopAnimation()
        
        // Clean up resources if we're navigating away from this VC entirely
        if isMovingFromParent {
            popupView.removeFromSuperview()
            popupView = nil
        }
    }
    
    private func setupAnimation() {
        // Reuse the existing popupView outlet
        popupView.animation = Animation.named("check1")
        popupView.contentMode = .scaleAspectFit
        popupView.frame = CGRect(x: 0, y: 0, width: 350, height: 350)
        popupView.center = view.center
        popupView.stop() // Start with animation paused
    }
    
    private func startAnimation() {
        // Play animation once (use .loop if you need repeated playback)
        popupView.play(loopMode: .playOnce) { finished in
            if finished {
                print("Animation completed naturally")
            }
        }
        
        // Stop animation after 3 seconds (adjust the duration as needed)
        DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in
            self?.stopAnimation()
        }
    }
    
    private func stopAnimation() {
        guard popupView.isAnimationPlaying else { return }
        popupView.stop()
    }
    
    func animateIn(desiredView: UIView) {
        guard desiredView.superview == nil else { return } // Avoid duplicate subviews
        let backgroundView = self.view!
        backgroundView.addSubview(desiredView)
        
        desiredView.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)
        desiredView.alpha = 0
        desiredView.center = backgroundView.center
        
        UIView.animate(withDuration: 0.3) {
            desiredView.transform = .identity
            desiredView.alpha = 1
        }
    }
    
    func animateOut(desiredView: UIView) {
        UIView.animate(withDuration: 0.3, animations: {
            desiredView.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)
            desiredView.alpha = 0
        }, completion: { _ in
            desiredView.removeFromSuperview()
            // Ensure animation stops if we're removing the AnimationView
            (desiredView as? AnimationView)?.stop()
        })
    }
}

Key Improvements Explained #

• Reusable Animation Instance: The setupAnimation() method initializes the animation once, so we don't create redundant AnimationView objects that waste memory.
• Lifecycle Awareness: viewWillDisappear pauses the animation and cleans up resources when leaving the view, preventing background execution and memory leaks.
• Timed Stop: DispatchQueue.main.asyncAfter triggers the animation stop after your specified duration—just change the +3 to your desired number of seconds.
• Weak Self in Closures: Prevents retain cycles that would keep the view controller in memory unnecessarily.
• Duplicate View Prevention: Checks if a view is already in the hierarchy before adding it, avoiding messy view stacks and extra memory usage.

内容的提问来源于stack exchange，提问作者GurkanEsen