iOS:带有动画UITabBarItem的曲线AppTabBar

import UIKit

class CustomTabBarController: UITabBarController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置自定义动画
        for (index, item) in tabBar.items!.enumerated() {
            let customView = UIView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
            customView.backgroundColor = .blue
            customView.layer.cornerRadius = 20
            
            let animation = CAKeyframeAnimation(keyPath: "position")
            animation.values = [
                NSValue(cgPoint: CGPoint(x: 20 + index * 40, y: 20)),
                NSValue(cgPoint: CGPoint(x: 20 + index * 40, y: 60)),
                NSValue(cgPoint: CGPoint(x: 20 + index * 40, y: 20))
            ]
            animation.duration = 1.0
            animation.repeatCount = .infinity
            customView.layer.add(animation, forKey: "positionAnimation")
            
            item.customView = customView
        }
    }
}