在 UIPageControl 中为点添加边框

Question

我想在 UIPageControl 中为圆点添加边框颜色。这是它的小图片：

我可以通过 XCode 配置来放置第二个圆点，但我无法将第一个和第三个圆圈的内部设为空。有没有简单的方法可以实现？

谢谢:)

Answer 1

已编辑- Swift 3 & 4 扩展 以获得相同的结果-

extension UIPageControl {

    func customPageControl(dotFillColor:UIColor, dotBorderColor:UIColor, dotBorderWidth:CGFloat) {
        for (pageIndex, dotView) in self.subviews.enumerated() {
            if self.currentPage == pageIndex {
                dotView.backgroundColor = dotFillColor
                dotView.layer.cornerRadius = dotView.frame.size.height / 2
            }else{
                dotView.backgroundColor = .clear
                dotView.layer.cornerRadius = dotView.frame.size.height / 2
                dotView.layer.borderColor = dotBorderColor.cgColor
                dotView.layer.borderWidth = dotBorderWidth
            }
        }
    }

}

要使用它，请在 viewDidLoad() 或 viewDidAppear() 中编写以下代码

pageControl.customPageControl(dotFillColor: .orange, dotBorderColor: .green, dotBorderWidth: 2)

在Objective-C中使用下面的代码-

- (void) customPageControlWithFillColor:(UIColor*)dotFillColor borderColor:(UIColor*)dotBorderColor borderWidth:(CGFloat)dotBorderWidth {
    for (int pageIndex = 0; pageIndex < _pageControl.numberOfPages; pageIndex++) {
        UIView* dotView = [_pageControl.subviews objectAtIndex:pageIndex];
        if (_pageControl.currentPage == pageIndex) {
            dotView.backgroundColor = dotFillColor;
            dotView.layer.cornerRadius = dotView.frame.size.height / 2;
        } else {
            dotView.backgroundColor = [UIColor clearColor];
            dotView.layer.cornerRadius = dotView.frame.size.height / 2;
            dotView.layer.borderColor = dotBorderColor.CGColor;
            dotView.layer.borderWidth = dotBorderWidth;
        }
    }
}

输出-

Answer 2

UIPageControl 当前可用的属性无法做到这一点。但是您可以通过集成任何模仿 iOS UIPageControl.

功能的 third party 页面控件来实现

_{其他回答打了补丁。我非常不同意这个解决方案。}

Answer 3

我正在使用 SMPageControl。这是一个用 Objective-C 编写的非常棒的框架，因此它可以使用 Swift 2 和 Swift 3.

用法完全简单：

pod 'SMPageControl'

然后在你的 PageViewController:

import SMPageControl

class MyController: UIPageViewController {

     var pageControl = SMPageControl()

     override func viewDidLoad() {
        super.viewDidLoad()

        stylePageControl()
    }

private func stylePageControl() {

    pageControl = SMPageControl(frame: CGRect(x: 0, y: self.view.frame.size.height - 50, width: self.view.frame.size.width, height: 50))
    pageControl.numberOfPages = yourPageControllerArray.count

//  the first (first) picture is the item in the bar, that is unused
//  the second (currentFirst) is an item that we use, when this is the current active page
//  in this example, we don't have dots, but we use "pictues" as dots

    let first = UIImage(named: "pageHome")?.imageWithColor(UIColor.grayColor())
    let currentFirst = first?.imageWithColor(UIColor.whiteColor())

    pageControl.setImage(first, forPage: 0)
    pageControl.setCurrentImage(currentFirst, forPage: 0)

    let second = UIImage(named: "pageMusic")?.imageWithColor(UIColor.grayColor())
    let currentSecond = second?.imageWithColor(UIColor.whiteColor())

    pageControl.setImage(second, forPage: 1)
    pageControl.setCurrentImage(currentSecond, forPage: 1)

    pageControl.indicatorMargin = 30.0 // this is the space between the dots

    self.view.addSubview(pageControl)
}

我用过的 UIImage 扩展：

extension UIImage {

    func imageWithColor(color1: UIColor) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
        color1.setFill()

        let context = UIGraphicsGetCurrentContext()! as CGContextRef
        CGContextTranslateCTM(context, 0, self.size.height)
        CGContextScaleCTM(context, 1.0, -1.0);
        CGContextSetBlendMode(context, CGBlendMode.Normal)

        let rect = CGRectMake(0, 0, self.size.width, self.size.height) as CGRect
        CGContextClipToMask(context, rect, self.CGImage!)
        CGContextFillRect(context, rect)

        let newImage = UIGraphicsGetImageFromCurrentImageContext()! as UIImage
        UIGraphicsEndImageContext()

        return newImage
    }

}

结果如下所示：

现在我们当然可以使用彩色点作为图像，（空白为未使用，颜色填充为已使用）然后我们就会得到要求的结果。

Answer 4

SWIFT 来自@RiosK

的 3 个版本

func updatePageControl() {
    for (index, dot) in pageControl.subviews.enumerated() {
        if index == pageControl.currentPage {
            dot.backgroundColor = dotColor
            dot.layer.cornerRadius = dot.frame.size.height / 2;
        } else {
            dot.backgroundColor = UIColor.clear
            dot.layer.cornerRadius = dot.frame.size.height / 2
            dot.layer.borderColor = dotColor.cgColor
            dot.layer.borderWidth = dotBorderWidth
        }
    }
}

Answer 5

另一种方法是使用正确尺寸的图案图像（目前直径为 7 磅）。结果如下所示：

这是如何完成的：

let image = UIImage.outlinedEllipse(size: CGSize(width: 7.0, height: 7.0), color: .darkGray)
self.pageControl.pageIndicatorTintColor = UIColor.init(patternImage: image!)
self.pageControl.currentPageIndicatorTintColor = .darkGray

它使用这个简单的小扩展 UIImage:

/// An extension to `UIImage` for creating images with shapes.
extension UIImage {

    /// Creates a circular outline image.
    class func outlinedEllipse(size: CGSize, color: UIColor, lineWidth: CGFloat = 1.0) -> UIImage? {

        UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
        guard let context = UIGraphicsGetCurrentContext() else {
                return nil
        }

        context.setStrokeColor(color.cgColor)
        context.setLineWidth(lineWidth)
        // Inset the rect to account for the fact that strokes are
        // centred on the bounds of the shape.
        let rect = CGRect(origin: .zero, size: size).insetBy(dx: lineWidth * 0.5, dy: lineWidth * 0.5)
        context.addEllipse(in: rect)
        context.strokePath()

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

这样做的缺点是，如果点大小在 OS 更新中发生变化，图像会看起来很奇怪，因为它会被平铺或剪裁。

Answer 6

需要在viewDidAppear中添加这个

 for (int i = 0; i < _pageControl.numberOfPages; i++) {
        UIView* dot = [_pageControl.subviews objectAtIndex:i];
        if (i == _pageControl.currentPage) {
            dot.backgroundColor = [UIColor whiteColor];
            dot.layer.cornerRadius = dot.frame.size.height / 2;
        } else {
            dot.backgroundColor = [UIColor clearColor];
            dot.layer.cornerRadius = dot.frame.size.height / 2;
            dot.layer.borderColor = [UIColor whiteColor].CGColor;
            dot.layer.borderWidth = 1;
        }
    }

Answer 7

只需添加这两行并添加所需的图像!!

pageControl.currentPageIndicatorTintColor  = UIColor.init(patternImage: UIImage(named: "slider_selected")!)

pageControl.pageIndicatorTintColor =  UIColor.init(patternImage: UIImage(named: "slider")!)

Answer 8

Swift 4。您可以分配 borderColor 然后观察 currentPage 属性以更改点的边框：

class CustomPageControl: UIPageControl {

    var borderColor: UIColor = .clear

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

    func updateBorderColor() {
        subviews.enumerated().forEach { index, subview in
            if index != currentPage {
                subview.layer.borderColor = borderColor.cgColor
                subview.layer.borderWidth = 1
            } else {
                subview.layer.borderWidth = 0
            }
        }
    }

}

Answer 9

Swift 5 版本

func customPageControl(dotFillColor: UIColor, dotBorderColor: UIColor, dotBorderWidth: CGFloat) {
    for (pageIndex, dotView) in self.subviews.enumerated() {
        dotView.backgroundColor = currentPage == pageIndex ? dotFillColor : .clear
        dotView.layer.cornerRadius = dotView.frame.size.height / 2
        dotView.layer.borderColor = dotBorderColor.cgColor
        dotView.layer.borderWidth = dotBorderWidth
    }
}

Answer 10

Luke Rogers的解决方案，写在objective-c:

-(UIImage *) outlinedEllipse:(CGSize)size color: (UIColor*) lineColor width:(CGFloat) lineWidth {
        UIGraphicsBeginImageContextWithOptions(size, false, 0.0);

        CGContextRef context = UIGraphicsGetCurrentContext();
        if (context == NULL) {
            return NULL;
        }

        CGContextSetStrokeColorWithColor(context, lineColor.CGColor);
        CGContextSetLineWidth(context, lineWidth);
        // Inset the rect to account for the fact that strokes are
        // centred on the bounds of the shape.

        CGRect rect = CGRectInset(CGRectMake(0, 0, 7.0f, 7.0f), lineWidth * 0.5, lineWidth * 0.5);
        CGContextAddEllipseInRect(context, rect);
        CGContextStrokePath(context);

        UIImage* image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return image;
}

Answer 11

现代卢克·罗杰斯（elk_cloner 说它对 ios14 来说不够现代）

extension UIImage
{
// 
    // modernized Luke Rogers
    class func outlinedEllipse(size: CGSize, color: UIColor, lineWidth: CGFloat = 1.0) -> UIImage? {

        let renderer = UIGraphicsImageRenderer(size: size)
        let image = renderer.image { context in

            color.setFill()
            
            context.cgContext.setLineWidth(lineWidth)
            // Inset the rect to account for the fact that strokes are
            // centred on the bounds of the shape.
            let rect = CGRect(origin: .zero, size: size).insetBy(dx: lineWidth * 0.5, dy: lineWidth * 0.5)
            context.cgContext.strokeEllipse(in: rect)
        }
        return image
    }
    
}

Answer 12

请尝试 UIPageControl 的这个自定义子类。 iOS 14 允许使用 SFSymbol 设置指标图像。

class BorderedPageControl: UIPageControl {

    var selectionColor: UIColor = .black
    
    override var currentPage: Int {
        didSet {
            updateBorderColor()
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        currentPageIndicatorTintColor = selectionColor
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    func updateBorderColor() {
        if #available(iOS 14.0, *) {
            let smallConfiguration = UIImage.SymbolConfiguration(pointSize: 8.0, weight: .bold)
            let circleFill = UIImage(systemName: "circle.fill", withConfiguration: smallConfiguration)
            let circle = UIImage(systemName: "circle", withConfiguration: smallConfiguration)
            for index in 0..<numberOfPages {
                if index == currentPage {
                    setIndicatorImage(circleFill, forPage: index)
                } else {
                    setIndicatorImage(circle, forPage: index)
                }
            }
            pageIndicatorTintColor = selectionColor
        } else {
            subviews.enumerated().forEach { index, subview in
                if index != currentPage {
                    subview.layer.borderColor = selectionColor.cgColor
                    subview.layer.borderWidth = 1
                } else {
                    subview.layer.borderWidth = 0
                }
            }
        }
    }
}

在 UIPageControl 中为点添加边框

Add border for dots in UIPageControl

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