Swift - UIScrollView

1、UIScrollView滚动视图的用法

import UIKit
class ViewController: UIViewController,UIScrollViewDelegate{
    
    var scrollView:UIScrollView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        scrollView = UIScrollView()
        scrollView.frame = self.view.bounds
        scrollView.delegate = self
        let imageView = UIImageView(image: UIImage(named: "welcome_page"))
        scrollView.contentSize = imageView.bounds.size
        scrollView.addSubview(imageView)
        scrollView.minimumZoomScale = 0.1//最小比例
        scrollView.maximumZoomScale = 3 //最大比例
        self.view.addSubview(scrollView)
        
    }
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        print("x:\(scrollView.contentOffset.x) y:\(scrollView.contentOffset.y)")
    }
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        for subview:AnyObject in scrollView.subviews{
            if subview.isKind(of: UIImageView.self){
                return subview as? UIView
            }
        }
        return nil
    }
}

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