Paging using UIScrollView - ios

Question

I'm trying to display multiple images using a UIScrollView and a page control, think screenshots of apps on the App Store. Yet for some reason, my UIScrollView is not scrolling. I checked, and UISCrollView's contentSize's width is larger than the UIScrollView's width. It might also be worth noting that I put the page control in the UIScrollView, so that it displays on top of the pictures. My code is as follows:
import UIKit
class ItemDetailViewController: UIViewController, UIScrollViewDelegate {
#IBOutlet weak var scrollView: UIScrollView!
#IBOutlet weak var pageControl: UIPageControl!
var itemSelected: Item!
var pageViews: [UIImageView?] = []
var pageCount: Int!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
pageCount = itemSelected.images.count
pageControl.currentPage = 0
pageControl.numberOfPages = pageCount
for _ in 0..<pageCount {
pageViews.append(nil)
}
scrollView.frame.size = CGSizeMake(view.frame.width, view.frame.height/2.0)
let pageSize = scrollView.frame.size
scrollView.contentSize = CGSizeMake(pageSize.width * CGFloat(pageCount), pageSize.height)
loadVisiblePages()
scrollView.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
tabBarController?.tabBar.hidden = true
}
override func viewWillDisappear(animated: Bool) {
super.viewDidDisappear(animated)
tabBarController?.tabBar.hidden = false
}
// MARK: - Helper Functions
func loadPage(page: Int){
if page < 0 || page >= pageCount {
// page outside of range, do nothing
return
}
if let pageView = pageViews[page] {
// page already loaded, do nothing
return
} else {
var frame = scrollView.bounds
frame.origin.x = frame.size.width * CGFloat(page)
frame.origin.y = 0.0
let newPageView = UIImageView(image: itemSelected.images[page])
newPageView.contentMode = .ScaleToFill
newPageView.frame = frame
scrollView.addSubview(newPageView)
pageViews[page] = newPageView
}
}
func purgePage(page: Int){
if page < 0 || page >= pageCount {
// page outside of range, do nothing
return
}
if let pageView = pageViews[page]{
pageView.removeFromSuperview()
pageViews[page] = nil
}
}
func loadVisiblePages(){
let pageWidth = scrollView.frame.size.width
let page = Int(floor(scrollView.contentOffset.x * 2.0 + pageWidth)/(2.0 * pageWidth))
pageControl.currentPage = page
let firstPage = page - 1
let lastPage = page + 1
for var index = 0; index < firstPage; index++ {
purgePage(index)
}
for index in firstPage ... lastPage {
loadPage(index)
}
for var index = lastPage + 1; index < itemSelected.images.count; index++ {
purgePage(index)
}
}
// MARK: - Scroll View Delegate Methods
func scrollViewDidScroll(scrollView: UIScrollView) {
loadVisiblePages()
}
}
What could be causing the issue?

Answer 1

Better use UIPageViewController is u want only show images.
u can see tutorial how do it there there