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)  }