實(shí)現(xiàn)思路
代碼實(shí)現(xiàn)
class AppBannerView: UIScrollView,UIScrollViewDelegate{
var pageChangeDelegate:PageChangeDelegate?
//記錄當(dāng)前的page
var currentPage = 0
var photos:[String]?
var autoScroll = true
var nsTimer:NSTimer?
init(frame:CGRect,photos:[String]!){
self.photos = photos
super.init(frame: frame)
initView()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func awakeFromNib() {
initView()
}
func initView(){
self.delegate = self
self.pagingEnabled = true
self.showsHorizontalScrollIndicator = false
self.showsVerticalScrollIndicator = true
for (var i = 0;i<3;i++){
let view = UIImageView(frame: CGRectMake(self.bounds.width*CGFloat(i), 0, self.bounds.width, self.bounds.height))
view.contentMode = UIViewContentMode.ScaleToFill
var imageUrl:NSURL?
if i == 0{
imageUrl = NSURL(string: photos![photos!.count-1])
}else if i == 2{
imageUrl = NSURL(string: photos![1])
}else{
imageUrl = NSURL(string: photos![0])
}
view.sd_setImageWithURL(imageUrl)
self.addSubview(view)
}
self.contentSize = CGSizeMake(self.bounds.width*CGFloat(photos!.count), 0)
self.setContentOffset(CGPoint(x: self.bounds.width, y: 0), animated: false)
if autoScroll{
nsTimer = NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: Selector("startScroll"), userInfo: nil, repeats: true)
}
}
func showPageIndex(index:Int){
if index > currentPage{
self.setContentOffset(CGPointMake(self.bounds.width*2, 0), animated: true)
}else{
self.setContentOffset(CGPointMake(0, 0), animated: true)
}
}
func setDataSource(photos:[String]!){
self.photos = photos
}
func scrollViewDidScroll(scrollView: UIScrollView) {
if abs((scrollView.contentOffset.x - self.bounds.width)) >= self.bounds.width{
if scrollView.contentOffset.x == 0{
currentPage = currentPage - 1
if currentPage == -1 {
currentPage = photos!.count-1
}
}else{
currentPage = currentPage + 1
if currentPage == photos!.count{
currentPage = 0
}
}
pageChangeDelegate?.pageChange(currentPage)
self.setContentOffset(CGPoint(x: self.bounds.width, y: 0), animated: false)
let imageView = self.subviews[1] as! UIImageView
imageView.sd_setImageWithURL(NSURL(string: photos![currentPage])!)
let leftImageView = self.subviews[0] as! UIImageView
if currentPage-1 == -1{
leftImageView.sd_setImageWithURL(NSURL(string: photos![photos!.count-1]))
}else{
leftImageView.sd_setImageWithURL(NSURL(string: photos![currentPage-1]))
}
let rightImageView = self.subviews[2] as! UIImageView
if currentPage+1 == photos!.count {
rightImageView.sd_setImageWithURL(NSURL(string: photos![0]))
}else{
rightImageView.sd_setImageWithURL(NSURL(string: photos![currentPage+1]))
}
}
}
func startScroll(){
self.showPageIndex(currentPage+1)
}
func stopScroll(){
nsTimer?.invalidate()
}
//默認(rèn)滾動(dòng)位置 屏幕的寬度按
func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
}
func setBannerViewAutoScroll(autoScroll:Bool){
self.autoScroll = autoScroll
if !autoScroll{
stopScroll()
}
}
}
protocol PageChangeDelegate{
func pageChange(index:Int)
}
