SWIFT用ScrollView加图片制作Banner

网上参考OBJC写的用ScrollView图片轮播效果，照着画了个，先上效果图:

附上代码：

 @IBOutlet weak var pc: UIPageControl!
     @IBOutlet weak var sv:UIScrollView!

     var timer:NSTimer!

     override func viewDidLoad() {
         super.viewDidLoad()

         for i in ...{ //loading the images
             let image = UIImage(named: "pic\(i).jpg")!
             let x = CGFloat(i - ) * self.view.frame.width //这一步获取ScrollView的宽度时我用IPHONE6实体机测试是320，右边会出现第二张图片的一部分，最后还是用ROOT VIEW的宽度
             var imageView = UIImageView(frame: CGRectMake(x, , self.view.frame.width, sv.bounds.height))
             imageView.image = image
             sv.pagingEnabled = true
             sv.showsHorizontalScrollIndicator = false
             sv.scrollEnabled = true
             sv.addSubview(imageView)
             sv.delegate = self
         }

         sv.contentSize = CGSizeMake((self.view.frame.width * ), sv.frame.height)
         pc.numberOfPages =
         pc.currentPageIndicatorTintColor = UIColor.redColor()
         pc.pageIndicatorTintColor = UIColor.whiteColor()
         addTimer()

     }

     func scrollViewDidScroll(scrollView: UIScrollView) {
         let width = self.view.frame.width
         let offsetX = scrollView.contentOffset.x
         let index = (offsetX + width / ) / width
         pc.currentPage = Int(index)
     }

     func scrollViewWillBeginDragging(scrollView: UIScrollView) {
         removeTimer()
     }

     func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {
         addTimer()
     }

     func addTimer() {
         timer = NSTimer.scheduledTimerWithTimeInterval(, target: self, selector: "nextImage", userInfo: nil, repeats: true)
     }

     func removeTimer() {
         timer.invalidate()
     }

     func nextImage() {
         var pageIndex = pc.currentPage
         if pageIndex ==  {
             pageIndex =
         } else {
             pageIndex++
         }

         var offsetX = CGFloat(pageIndex) * self.view.frame.width
         sv.setContentOffset(CGPointMake(offsetX, ), animated: true)
     }