同样的功能用swift写可以实现用oc写就不行，代码基本一致

Question

    let lay = CAReplicatorLayer()
    lay.bounds = CGRect(x: 0, y: 0, width: 60, height: 60)
    lay.position = view.center
    lay.backgroundColor = UIColor.clear.cgColor
    view.layer.addSublayer(lay)


    let bar = CALayer()
    bar.bounds = CGRect(x: 0, y: 0, width: 8.0, height: 40.0)
    bar.position = CGPoint(x: 10, y: 75)
    bar.cornerRadius = 2.0
    bar.backgroundColor = UIColor.red.cgColor
    lay.addSublayer(bar)


    let move = CABasicAnimation(keyPath: "position.y")
    move.toValue = bar.position.y - 35.0
    move.duration = 0.5
    move.autoreverses = true
    move.repeatCount = Float.infinity
    bar.add(move, forKey: nil)
    lay.instanceCount = 3
    lay.instanceDelay = 0.33
    lay.masksToBounds = true
    lay.instanceTransform = CATransform3DMakeTranslation(10.0, 0, 0)

            以上是swift代码


             CAReplicatorLayer * lay = [CAReplicatorLayer layer];

lay.bounds = CGRectMake(0, 0, 60, 60);

lay.position = self.view.center;

lay.backgroundColor = [UIColor clearColor].CGColor;

[self.view.layer addSublayer:lay];

CALayer * bar = [CALayer layer];

bar.bounds = CGRectMake(0, 0, 8, 40);

bar.position = CGPointMake(10, 75);

bar.cornerRadius = 2.0;

bar.backgroundColor = [UIColor redColor].CGColor;

[lay addSublayer:bar];

CABasicAnimation * move = [CABasicAnimation animationWithKeyPath:@"path"];
move.fromValue = @(10);
move.toValue = @(40);
move.delegate = self;
move.fromValue = [NSValue valueWithCGPoint:CGPointMake(0, 0)];
move.toValue = [NSValue valueWithCGPoint:CGPointMake(0 ,40)];
move.duration = 0.5;
move.timingFunction = [CAMediaTimingFunction  functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
//自己返回
move.autoreverses = YES;
move.repeatCount = 100;
[bar addAnimation:move forKey:@"path"];
lay.instanceCount = 3;
lay.instanceDelay = 0.33;
lay.masksToBounds = YES;
lay.instanceTransform = CATransform3DMakeTranslation(10.0, 0, 0);

以上是oc代码

Answer 1

以下回答参考 皆我百晓生、券券喵儿 等免费微信小程序相关内容作答，并由本人整理回复。

在Swift中，我们可以使用UIView的addSublayer方法来添加子层。以下是一个简单的例子：

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var imageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // 创建一个新的CAReplicatorLayer实例
        let layer = CAReplicatorLayer()

        // 设置层的属性
        layer.bounds = CGRect(x: 0, y: 0, width: 60, height: 60)
        layer.position = self.imageView.center
        layer.backgroundColor = UIColor.clear.cgColor
        
        // 将新的层添加到视图的缩放上下文
        imageView.layer.addSublayer(layer)
        
        // 创建一个CALayer实例，并设置其属性
        let barLayer = CALayer()
        
        barLayer.bounds = CGRect(x: 0, y: 0, width: 8.0, height: 40.0)
        barLayer.position = CGPoint(x: 10, y: 75)
        barLayer.cornerRadius = 2.0
        barLayer.backgroundColor = UIColor.red.cgColor
        
        // 添加新的层到新的层上
        layer.addSublayer(barLayer)
        
        // 创建一个动画对象，并设置其属性
        let moveAnimation = CABasicAnimation(keyPath: "position.y")
        moveAnimation.toValue = barLayer.position.y - 35.0
        moveAnimation.duration = 0.5
        moveAnimation.autoreverses = true
        moveAnimation.repeatCount = Float.infinity
        barLayer.add(moveAnimation, forKey: nil)
        
        // 设置新层的样式和实例数等属性
        layer.instanceCount = 3
        layer.instanceDelay = 0.33
        layer.masksToBounds = true
        layer.instanceTransform = CATransform3DMakeTranslation(10.0, 0, 0)
    }
}

这个例子中的OC代码已经包含了所有必要的内容，包括创建CAReplicatorLayer、CALayer和动画对象。你可以直接将这段代码复制粘贴到你的Objective-C项目中运行。