I am creating a paging UIScrollView following this tutorial.
This is the Swift code which allow paging of images with UIScrollView. However, it has a limitation. I am unable to zoom the images.
class PagedScrollViewController: UIViewController, UIScrollViewDelegate {
@IBOutlet var scrollView: UIScrollView!
@IBOutlet var pageControl: UIPageControl!
var pageImages: [UIImage] = []
var pageViews: [UIImageView?] = []
override func viewDidLoad() {
super.viewDidLoad()
// 1
pageImages = [UIImage(named:"photo1.png")!,
UIImage(named:"photo2.png")!,
UIImage(named:"photo3.png")!,
UIImage(named:"photo4.png")!,
UIImage(named:"photo5.png")!]
let pageCount = pageImages.count
// 2
pageControl.currentPage = 0
pageControl.numberOfPages = pageCount
// 3
for _ in 0..<pageCount {
pageViews.append(nil)
}
// 4
let pagesScrollViewSize = scrollView.frame.size
scrollView.contentSize = CGSizeMake(pagesScrollViewSize.width * CGFloat(pageImages.count), pagesScrollViewSize.height)
// 5
loadVisiblePages()
}
func loadPage(page: Int) {
if page < 0 || page >= pageImages.count {
// If it's outside the range of what you have to display, then do nothing
return
}
// 1
if let pageView = pageViews[page] {
// Do nothing. The view is already loaded.
} else {
// 2
var frame = scrollView.bounds
frame.origin.x = frame.size.width * CGFloat(page)
frame.origin.y = 0.0
// 3
let newPageView = UIImageView(image: pageImages[page])
newPageView.contentMode = .ScaleAspectFit
newPageView.frame = frame
scrollView.addSubview(newPageView)
// 4
pageViews[page] = newPageView
}
}
func purgePage(page: Int) {
if page < 0 || page >= pageImages.count {
// If it's outside the range of what you have to display, then do nothing
return
}
// Remove a page from the scroll view and reset the container array
if let pageView = pageViews[page] {
pageView.removeFromSuperview()
pageViews[page] = nil
}
}
func loadVisiblePages() {
// First, determine which page is currently visible
let pageWidth = scrollView.frame.size.width
let page = Int(floor((scrollView.contentOffset.x * 2.0 + pageWidth) / (pageWidth * 2.0)))
// Update the page control
pageControl.currentPage = page
// Work out which pages you want to load
let firstPage = page - 1
let lastPage = page + 1
// Purge anything before the first page
for var index = 0; index < firstPage; ++index {
purgePage(index)
}
// Load pages in our range
for var index = firstPage; index <= lastPage; ++index {
loadPage(index)
}
// Purge anything after the last page
for var index = lastPage+1; index < pageImages.count; ++index {
purgePage(index)
}
}
func scrollViewDidScroll(scrollView: UIScrollView!) {
// Load the pages that are now on screen
loadVisiblePages()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
How to make the images zoomable?
