使用UIScrollView进行分页

我试图使用UIScrollView和一个页面控件显示多个图像，请考虑App Store上的应用程序截图。但由于某种原因，我UIScrollView不滚动。我检查了，UISCrollView's contentSize的宽度大于UIScrollView's的宽度。也可能值得注意的是，我将页面控件放在UIScrollView中，以便它显示在图片的顶部。我的代码如下：使用UIScrollView进行分页

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() 
} 
}

什么可能导致这个问题？

来源

2015-07-11 modsoussi

改为在viewDidLayoutSubviews中设置滚动视图的内容大小。 –

感谢您的快速响应，但仍然无法滚动。 – modsoussi

你在哪里初始化选项？似乎设置pageCount时它是空的。看起来像pageCount = 0. –

更好的使用UIPageViewController是你想只显示图像。你可以看到教程如何在那里there

来源

2015-07-11 05:37:18

这实际上是我正在寻找！谢谢！ – modsoussi

非常欢迎;） –

使用UIScrollView进行分页

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