我们在使用APP的时候，有时会发现有些图片可以通过两指进行放大、缩小，今天就实现这样的一种效果，比较简单，不喜勿喷。。。。
var imageVi:UIImageView! = nil
var myScrollV:UIScrollView! = nil
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
imageVi = UIImageView.init(image: UIImage.init(named: "liwu.jpg"))
setUpScrollView()
myScrollV.delegate = self
setZoomScaleFor(srollViewSize: myScrollV.bounds.size)
myScrollV.zoomScale = myScrollV.minimumZoomScale
recenterImage()
}
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
setZoomScaleFor(srollViewSize: myScrollV.bounds.size)
if myScrollV.zoomScale < myScrollV.minimumZoomScale {
myScrollV.zoomScale = myScrollV.minimumZoomScale
}
recenterImage()
}
private func recenterImage() {
let scrollViewSize = myScrollV.bounds.size
let imageViewSize = imageVi.frame.size
let horizontalSpace = imageViewSize.width < scrollViewSize.width ? (scrollViewSize.width - imageViewSize.width) / 2.0 : 0
let verticalSpace = imageViewSize.height < scrollViewSize.height ? (scrollViewSize.height - imageViewSize.width) / 2.0 :0
myScrollV.contentInset = UIEdgeInsetsMake(verticalSpace, horizontalSpace, verticalSpace, horizontalSpace)
}
private func setZoomScaleFor(srollViewSize: CGSize) {
let imageSize = imageVi.bounds.size
let widthScale = srollViewSize.width / imageSize.width
let heightScale = srollViewSize.height / imageSize.height
let minimunScale = min(widthScale, heightScale)
myScrollV.minimumZoomScale = minimunScale
myScrollV.maximumZoomScale = 3.0
}
private func setUpScrollView() {
myScrollV = UIScrollView(frame: view.bounds)
myScrollV.autoresizingMask = [.flexibleWidth, .flexibleHeight]
myScrollV.backgroundColor = UIColor.clear
myScrollV.contentSize = imageVi.bounds.size
myScrollV.addSubview(imageVi)
self.view.addSubview(myScrollV)
}
//MARK:---------UIScrollViewDelegate
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return self.imageVi
}
func scrollViewDidZoom(_ scrollView: UIScrollView) {
self.recenterImage()
}
效果图：（源码下载：https://github.com/hbblzjy/SwiftBigAndSmallDemo）