IOS 翻页

 1 import UIKit
 2
 3 class PageControlViewController：UIViewController,
 UIScrollViewDelegate {
 4
 5 var scrollView = UIScrollView()
 6 var pageControl = UIPageControl()
 7 var isPageControlUsed = false
 8 override func viewDidLoad() {
 9 super.viewDidLoad()
 10 var screenFrame = UIScreen.main.bounds
 11 let screenWidth = screenFrame.size.width
 12 let screenHeight = screenFrame.size.height
 13
 14 scrollView.frame = screenFrame
 15 scrollView.isPagingEnabled = true
 16 scrollView.contentSize = CGSize(width：screenWidth
 2, height：screenHeight)
 17 scrollView.backgroundColor = UIColor.black
 18 scrollView.delegate = self
 19
 20 let pcHeight：CGFloat = 50.0
 21 let pcRect = CGRect(x：0, y：screenHeight - pcHeight,
 width：screenWidth, height：pcHeight)
 22
 23 pageControl.frame = pcRect
 24 pageControl.numberOfPages = 2
 25 pageControl.currentPage = 0
 26 pageControl.backgroundColor = UIColor.gray
 27 pageControl.addTarget(self, action：
selector(PageControlViewController.pageControlDidChanged(_：)),
for：UIControlEvents.valueChanged)
 28
 29 let firstController = FirstViewController()
 30 screenFrame.origin.x = 0
 31 firstController.view.frame = screenFrame
 32
 33 let secondController = SecondViewController()
 34 screenFrame.origin.x = screenFrame.size.width
 35 secondController.view.frame = screenFrame
 36
 37 scrollView.addSubview(firstController.view)
 38 scrollView.addSubview(secondController.view)
 39
 40 self.view.addSubview(scrollView)
 41 self.view.addSubview(pageControl)
 42 }
 43
 44 func pageControlDidChanged(_ sender：AnyObject)
 45 {
 46 let crtPage = (CGFloat)(pageControl.currentPage)
 47 var frame = scrollView.frame
 48 frame.origin.x = frame.size.width * crtPage
 49 frame.origin.y = 0
 50
 51 scrollView.scrollRectToVisible(frame, animated：true)
 52 isPageControlUsed = true
 53 }
 54
 55 func scrollViewDidScroll(_ scrollView：UIScrollView)
 56 {
 57 if(！isPageControlUsed)
 58 {
 59 let pageWidth = scrollView.frame.size.width
 60 let page = floor((scrollView.contentOffset.x -
 pageWidth/2)/pageWidth) + 1
 61 pageControl.currentPage = Int(page)
 62 }
 63 }
 64
 65 func scrollViewDidEndDecelerating(_ scrollView：
 UIScrollView)
 66 {
 67 isPageControlUsed = false
 68 }
 69 }