SWIFT用ScrollView加图片制作Banner

@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)
}