swift 实践- 14 -- UIScrollView

import UIKit

class ViewController: UIViewController ,UIScrollViewDelegate{

override func viewDidLoad() {

super.viewDidLoad()

let scrollView = UIScrollView.init()

scrollView.frame = self.view.bounds

let imageView = UIImageView.init(image: UIImage.init(named: "1"))

scrollView.contentSize = imageView.bounds.size

scrollView.addSubview(imageView)

self.view.addSubview(scrollView)

// 手势缩放大小

// 要实现放大缩小功能, 需要指定 UIScrollView 的允许缩放的最大和最小比例 (默认都是 1.0)

// 同时 delegate 属性指定一个委托类, 委托类要继承 UIScrollViewDelegate 协议, 并实现 viewForZooming 方法

scrollView.minimumZoomScale = 0.1 //最小比例

scrollView.maximumZoomScale = 3 //最大比例

scrollView.delegate = self

}

func viewForZooming(in scrollView: UIScrollView) -> UIView? {

for subview : AnyObject in scrollView.subviews {

if subview.isKind(of: UIImageView.classForCoder()) {

return subview as? UIView

}

}

return nil

}

//视图滚动中一直触发

func scrollViewDidScroll(_ scrollView: UIScrollView) {

print("x:\(scrollView.contentOffset.x) y:\(scrollView.contentOffset.y)")

}

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

// Dispose of any resources that can be recreated.

}

}