Question

当我需要自定义我的UIPageControl时，我使用了this和this解决方案。

稍微修改它以获得新版本的swift：

class myPageControl: UIPageControl {
    var activeImage: UIImage!
    var inactiveImage: UIImage!

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        activeImage = UIImage(named: "active.png")!
        inactiveImage = UIImage(named: "inactive.png")!
    }

    func updateDots()
    {
        for i in 0 ..< self.subviews.count
        {
            let dot : UIImageView = imageViewForSubview(self.subviews[i])
            if (i == self.currentPage) {
                dot.image = activeImage
            }
            else {
                dot.image = inactiveImage
            }
        }
    }

    func imageViewForSubview(view: UIView) -> UIImageView {
        var dot: UIImageView? = nil
        if (view.isKindOfClass(UIView)) {
            for subview: UIView in view.subviews {
                if (subview is UIImageView) {
                    dot = (subview as! UIImageView)
                }
            }
            if dot == nil {
                dot = UIImageView(frame: CGRectMake(0.0, 0.0, view.frame.size.width, view.frame.size.height))
                view.addSubview(dot!)
            }
        }
        else {
            dot = (view as! UIImageView)
        }
        return dot!
    }

    func setPage(page: Int) {
        super.currentPage = page
        self.updateDots()
    }
}

我的问题是，当您第一次启动应用时，我无法更改图片。它仅在页面更改时更改。

在viewDidLoad()中，我添加了setPage(0)和updateDots()，但没有结果。我能做错什么？

Answer 1

Swift 3.0 ...你知道你是否接受陈述的风险：＆＃34;修改现有控件的子视图是脆弱的＆＃34;。

您必须致电＆＃34; updateDots（）＆＃34;在viewDidAppear（）和页面控件的valueChanged处理程序。

{{1}}

Answer 2

我改进了@CodenameDuchess的答案。您还可以在xib / storyboard上自定义图像。

class CustomPageControl: UIPageControl {

@IBInspectable var currentPageImage: UIImage?

@IBInspectable var otherPagesImage: UIImage?

override var numberOfPages: Int {
    didSet {
        updateDots()
    }
}

override var currentPage: Int {
    didSet {
        updateDots()
    }
}

override func awakeFromNib() {
    super.awakeFromNib()
    pageIndicatorTintColor = .clear
    currentPageIndicatorTintColor = .clear
    clipsToBounds = false
}

private func updateDots() {

    for (index, subview) in subviews.enumerated() {
        let imageView: UIImageView
        if let existingImageview = getImageView(forSubview: subview) {
            imageView = existingImageview
        } else {
            imageView = UIImageView(image: otherPagesImage)

            imageView.center = subview.center
            subview.addSubview(imageView)
            subview.clipsToBounds = false
        }
        imageView.image = currentPage == index ? currentPageImage : otherPagesImage
    }
}

private func getImageView(forSubview view: UIView) -> UIImageView? {
    if let imageView = view as? UIImageView {
        return imageView
    } else {
        let view = view.subviews.first { (view) -> Bool in
            return view is UIImageView
        } as? UIImageView

        return view
    }
}
}

Answer 3

您可以使用UIStackView来达到您想要的效果。

将activeImageView和其他inactiveImageView放入aStackView。而不仅仅是更改activeImageView中的scrollViewDidScroll(_:)索引。

func scrollViewDidScroll(_ scrollView: UIScrollView) {
  let index = Int(scrollView.contentOffset.x / scrollView.frame.width)
  aStackView.insertArrangedSubview(activeImageView, at: index)
}

PS。 UIStackView的insertArrangedSubview(_:at:)只是更新了排列的子视图的堆栈索引（如果它已经在arrangeSubviews列表中）。

Answer 4

Apple已经为UIPageControll引入了一些新的API。从iOS 14开始，可以选择提供自定义图片。

这是支持iOS 14的更新代码

class CustomPageControl: UIPageControl {

@IBInspectable var currentPageImage: UIImage?

@IBInspectable var otherPagesImage: UIImage?

override var numberOfPages: Int {
    didSet {
        updateDots()
    }
}

override var currentPage: Int {
    didSet {
        updateDots()
    }
}

override func awakeFromNib() {
    super.awakeFromNib()
    if #available(iOS 14.0, *) {
        defaultConfigurationForiOS14AndAbove()
    } else {
        pageIndicatorTintColor = .clear
        currentPageIndicatorTintColor = .clear
        clipsToBounds = false
    }
}

private func defaultConfigurationForiOS14AndAbove() {
    if #available(iOS 14.0, *) {
        for index in 0..<numberOfPages {
            let image = index == currentPage ? currentPageImage : otherPagesImage
            setIndicatorImage(image, forPage: index)
        }

        // give the same color as "otherPagesImage" color.
        pageIndicatorTintColor = .gray
        
        // give the same color as "currentPageImage" color.
        currentPageIndicatorTintColor = .red 
        /*
         Note: If Tint color set to default, Indicator image is not showing. So, give the same tint color based on your Custome Image.
        */
    }
}

private func updateDots() {
    if #available(iOS 14.0, *) {
        defaultConfigurationForiOS14AndAbove()
    } else {
        for (index, subview) in subviews.enumerated() {
            let imageView: UIImageView
            if let existingImageview = getImageView(forSubview: subview) {
                imageView = existingImageview
            } else {
                imageView = UIImageView(image: otherPagesImage)
                
                imageView.center = subview.center
                subview.addSubview(imageView)
                subview.clipsToBounds = false
            }
            imageView.image = currentPage == index ? currentPageImage : otherPagesImage
        }
    }
}

private func getImageView(forSubview view: UIView) -> UIImageView? {
    if let imageView = view as? UIImageView {
        return imageView
    } else {
        let view = view.subviews.first { (view) -> Bool in
            return view is UIImageView
        } as? UIImageView

        return view
    }
}
}

使用点图像自定义UIPageControl

4 个答案: