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 1...6{ //loading the images
            let image = UIImage(named: "pic(i).jpg")!
            let x = CGFloat(i - 1) * 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, 0, 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 * 6), sv.frame.height)
        pc.numberOfPages = 6
        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 / 2) / width
        pc.currentPage = Int(index)
    }
    
    func scrollViewWillBeginDragging(scrollView: UIScrollView) {
        removeTimer()
    }
    
    func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        addTimer()
    }
    
    func addTimer() {
        timer = NSTimer.scheduledTimerWithTimeInterval(5, target: self, selector: "nextImage", userInfo: nil, repeats: true)
    }
    
    func removeTimer() {
        timer.invalidate()
    }

    
    func nextImage() {
        var pageIndex = pc.currentPage
        if pageIndex == 5 {
            pageIndex = 0
        } else {
            pageIndex++
        }
        
        var offsetX = CGFloat(pageIndex) * self.view.frame.width
        sv.setContentOffset(CGPointMake(offsetX, 0), animated: true)
    }