iOS swift scrollview 缩放报错

ERROR: scrollview运行时，手势放大报错：
 

2022-04-22 14:27:53.721664+0800 ScrollDemo2[4556:369749] [framework] CUIThemeStore: No theme registered with id=02022-04-22 14:27:55.405513+0800 ScrollDemo2[4556:369749] *** Terminating app due to uncaught exception 'NSGenericException', reason: 'The view returned from viewForZoomingInScrollView: must be a subview of the

以下是设置缩放代码源码 ：

class ViewController: UIViewController {

    @IBOutlet weak var scrollView: UIScrollView!
    @IBOutlet weak var checkmarkImg: UIImageView!
    override func viewDidLoad() {
        super.viewDidLoad()
       
    }

    override func viewWillLayoutSubviews() {
        scrollView.frame=view.bounds
        checkmarkImg.frame=view.bounds
    }

}

extension ViewController:UIScrollViewDelegate{
    
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return self.checkmarkImg
    }
}

解决方案：

返回scroll view里面的UIImageView的对象：self.checkmarkImg，而不是myScrollView

把return self.scrollView 改成： return self.checkmarkImg

效果：缩放前后效果