swift实现自动轮播图效果（UIScrollView+UIPageControl+Timer）

var pageControl:UIPageControl?
 var myscrollView:UIScrollView?
 var myTimer:Timer?
 var mycurrentPage:NSInteger?
 
 
 var courses = [
  ["name":"first","pic":"1.jpeg"],
  ["name":"second","pic":"2.jpeg"],
  ["name":"third","pic":"3.jpeg"]
 ]

 //添加scrollview
  self.addScrollView()
  //添加图片
  self.addImages()
  //添加pagecontrol
  self.addPageControl()
  
  mycurrentPage = 1
  
  //添加定时器
  self.setupTimer()

func addScrollView(){
  self.myscrollView = UIScrollView()
  self.myscrollView?.frame = CGRect(x:0,y:0,width:kScreenWidth,height:kScreenHeight/2)
  self.myscrollView?.contentSize = CGSize(width:kScreenWidth*3,height:kScreenHeight/2)
  self.myscrollView?.showsHorizontalScrollIndicator = false
  self.myscrollView?.showsVerticalScrollIndicator = false
  self.myscrollView?.scrollsToTop = false
  self.myscrollView?.delegate = self
  self.myscrollView?.isPagingEnabled = true
  self.view.addSubview(self.myscrollView!)

 }
 
 func addImages(){
  let size = self.myscrollView?.bounds.size
  for (seq,course) in courses.enumerated() {
   let page = UIView(frame:CGRect(x:0,y:64,width:kScreenWidth,height:kScreenHeight/2))
   let imageView=UIImageView(image:UIImage(named:course["pic"]!))
   imageView.frame = page.frame
   page.addSubview(imageView)
   page.backgroundColor = UIColor.gray
   let lab1 = UILabel(frame:CGRect(x:15,y:kScreenHeight/2-100,width:kScreenWidth-30,height:40))
   lab1.textAlignment = .center
   lab1.backgroundColor = UIColor.red
   lab1.text = course["name"]
   page.addSubview(lab1)
   
   page.frame = CGRect(x:CGFloat(seq)*(size?.width)!,y:0,width:(size?.width)!,height:(size?.height)!)
   self.myscrollView?.addSubview(page)
   
  }
 }
 
 func addPageControl(){
  self.pageControl = UIPageControl(frame:CGRect(x:kScreenWidth/2-50/2,y:kScreenHeight/2-40,width:50,height:35))
  self.pageControl?.backgroundColor = UIColor.blue
  self.pageControl?.numberOfPages = courses.count
  self.view.addSubview(self.pageControl!)
 }
 
 func setupTimer() {
  self.myTimer = Timer.init(timeInterval: 2.0, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
  RunLoop.main.add(self.myTimer!, forMode: RunLoopMode.defaultRunLoopMode)
  
//  DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 2) { 
//   self.myTimer?.fire()
//  }
  
 }
 
 func closeTimer(){
  self.myTimer?.invalidate()
  self.myTimer = nil
 }
 
 func timerAction(){
  self.pageControl?.currentPage += mycurrentPage!
  
  if self.pageControl?.currentPage == 0 || self.pageControl?.currentPage == 2 {
   mycurrentPage = -mycurrentPage!
  }
  self.myscrollView?.contentOffset = CGPoint(x:CGFloat(kScreenWidth)*CGFloat((pageControl?.currentPage)!),y:0)
 }

internal func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
  let page = Int(scrollView.contentOffset.x/scrollView.frame.size.width)
  self.pageControl?.currentPage = page
  
 }
 
 func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
  self.closeTimer()
 }
 
 func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
  self.setupTimer()
 }
 
 func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView) {
  self.pageControl?.currentPage = Int(scrollView.contentOffset.x/kScreenWidth)
 }