Add border for dots in UIPageControl

问题:

I want to add border color for dots in UIPageControl. Here is the small picture of it:

I am able to put second dot by configuring it from XCode but I cannot make the first and third circles' inside empty. Is there a simple way to achieve that?

Thanks :)

回答1:

That is not possible with the current properties available for UIPageControl. But you can do by integrating any third party page control which mimic the functionality of iOS UIPageControl.

_{Other answer has applied a patch. I highly disagreed with that solution.}

回答2:

Edited- Swift 3 & 4 extension to achieve the same result-

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
            }
        }
    }

}

to use it write below code in viewDidLoad() or viewDidAppear()

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

In Objective-C use below code-

- (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;
        }
    }
}

Output-

回答3:

Another approach would be to use a pattern image of the correct size (which currently is 7 points in diameter). Here's what the result looks like:

And here's how it's done:

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

Which uses this simple little extension to 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
    }
}

The downside of this is that if the dot size changes in an OS update, the image will look weird as it will be tiled or clipped.

回答4:

SWIFT 3 Version from @RiosK

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
        }
    }
}

回答5:

Swift 4. You can assign borderColor and then observe currentPage property to change dots' border:

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
            }
        }
    }

}

回答6:

I am using SMPageControl. It's a really awesome Framework written in Objective-C, so it's capable with Swift 2 and Swift 3.

The usage is completely simple:

pod 'SMPageControl'

Then in your 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)
}

UIImage Extension I've used:

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
    }

}

The result looks like this:

Now we could of course use colored dots as the images, (blank colored as unused and color-filled as used) then we would have the asked result.

回答7:

Just add this two lines and add the desired image !!

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

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

回答8:

Need to add this in viewDidAppear

 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;
        }
    }

回答9:

Swift 5 version

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
    }
}

回答10:

Luke Rogers's solution, written in 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;
}

回答11:

Modern Luke Rogers

extension UIImage
{
// https://stackoverflow.com/questions/35842040/add-border-for-dots-in-uipagecontrol
    // 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
    }

}