Question

我的scrollview不会调用它的viewdidscroll函数... 我很确定我的代码是“正确的”。所以我担心故事板面板中某处有一些选项。不会发布我在那里的所有内容的截图。所以我希望有人遇到同样的问题。

有什么想法吗？

这是一款快速的iphone ios应用程序。

import UIKit

class ViewController: UIViewController, UIScrollViewDelegate  {

    @IBOutlet var scrollView: UIScrollView!


    var imageGroup : [UIImage?] = []
    var containerViews : [UIImageView?] = []
    var containerView :UIImageView?
    var imgWidthMult : CGFloat = 2.121875
    let imageGroupCount : CGFloat?
    let containerHeight : CGFloat?
    let containerWidth : CGFloat?
    var imageCounter : Int = 0



    override func viewDidLoad() {
        super.viewDidLoad()
        // 1
        imageGroup = [
            UIImage(named: "bg_001")!,
            UIImage(named: "bg_002")!,
            UIImage(named: "bg_003")!,
            UIImage(named: "bg_004")!,
            UIImage(named: "bg_005")!,
            UIImage(named: "bg_006")!,
            UIImage(named: "bg_007")!,
            UIImage(named: "bg_008")!,
            UIImage(named: "bg_009")!,
            UIImage(named: "bg_010")!,
            UIImage(named: "bg_011")!,
            UIImage(named: "bg_012")!,
            UIImage(named: "bg_013")!,
            UIImage(named: "bg_014")!,
            UIImage(named: "bg_015")!,
            UIImage(named: "bg_016")!,
            UIImage(named: "bg_017")!,
            UIImage(named: "bg_018")!,
            UIImage(named: "bg_019")!,
            UIImage(named: "bg_020")!
        ]

        let imageGroupCount = CGFloat(imageGroup.count)
        println(imageGroupCount)


        // 3
        for i in 0..<imageGroup.count {
            containerViews.append(nil)
        }

        // 4

        let imagesScrollViewSize = UIScreen.mainScreen().applicationFrame;
        scrollView.contentSize = CGSizeMake(imagesScrollViewSize.height * imgWidthMult * CGFloat(imageGroup.count), imagesScrollViewSize.height)

        // 5
        let containerframe = UIScreen.mainScreen().applicationFrame;
        let containerHeight : CGFloat = containerframe.height
        let containerWidth : CGFloat = (imgWidthMult * containerHeight)

        loadVisibleImages()

        println("containerWidth")
        println(containerWidth)
        println(containerframe.size)
        println(scrollView.contentSize)




        return
    }

    // this loads images and should be adjusted and taken out of local scope


    func loadImage (imageCounter:Int) {
        let containerframe = UIScreen.mainScreen().applicationFrame;
        let containerHeight : CGFloat = containerframe.height
        let containerWidth : CGFloat = (imgWidthMult * containerHeight)

        if imageCounter < 0 || imageCounter >= imageGroup.count {
            // If it's outside the range of what you have to display, then do nothing
            return
        }

        // 1
        if let containerView = containerViews[imageCounter] {
            // Do nothing. The view is already loaded.
        } else {
            // 2
            var frame = UIScreen.mainScreen().applicationFrame;
            frame.origin.x = frame.size.height * CGFloat(imageCounter) * 2.121875
            frame.origin.y = 0.0
            frame.size = CGSize(width: containerWidth, height: containerHeight)

            // 3
            var newcontainerView = UIImageView(image: imageGroup[imageCounter])
            newcontainerView.contentMode = .ScaleAspectFit
            newcontainerView.frame = frame
            scrollView.addSubview(newcontainerView)


            containerViews[imageCounter] = newcontainerView
        }

    }

    func purgeImage(imageCounter:Int) {

        if imageCounter < 0 || imageCounter >= imageGroup.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 containerView = containerViews[imageCounter] {
            containerView.removeFromSuperview()
            containerViews[imageCounter] = nil
        }

    }


    func loadVisibleImages() {


        // First, determine which page is currently visible
        let containerframe = UIScreen.mainScreen().applicationFrame;
        let containerHeight : CGFloat = containerframe.height
        let containerWidth : CGFloat = (imgWidthMult * containerHeight)
        let pageWidth = (containerWidth * 2.121875)
        let imageCounter = Int(floor(scrollView.contentOffset.x / pageWidth))


        println(imageCounter)

        // Update the page control

        // Work out which pages you want to load
        let firstPage = imageCounter - 1
        let lastPage = imageCounter + 1


        // Purge anything before the first page
        for var index = 0; index < firstPage; ++index {
            purgeImage(index)
        }

        // Load pages in our range
        for var index = firstPage; index <= lastPage; ++index {
            loadImage(index)
        }

        // Purge anything after the last page
        for var index = lastPage+1; index < imageGroup.count; ++index {
            purgeImage(index)
        }
        println("loadVisibleImages")
    }





    func scrollViewDidScroll(scrollView: UIScrollView) {
        // Load the pages that are now on screen
        println("did scroll")
        loadVisibleImages()
        println("did scroll")

    }




    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

Answer 1

您需要将视图控制器指定为滚动视图的委托。 viewDidLoad中的某处添加：

scrollView.delegate = self

swift UIScrollView不会调用它的“didscroll”函数

1 个答案: