ios - 使用图像快速更改页面控制点

Question

我正在尝试用一些图像更改页面控件中的点..

这是我尝试过的代码:

import UIKit
class PageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {
// MARK: Data source functions.
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
    guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
        return nil
    }
   let previousIndex = viewControllerIndex - 1
    guard previousIndex >= 0 else {
        return orderedViewControllers.last
        // Uncommment the line below, remove the line above if you don't want the page control to loop.
        // return nil
    }
    guard orderedViewControllers.count > previousIndex else {
        return nil
    }
    return orderedViewControllers[previousIndex]
   }
   func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
    guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
        return nil
    }
    let nextIndex = viewControllerIndex + 1
    let orderedViewControllersCount = orderedViewControllers.count
    // the first view controller.
    guard orderedViewControllersCount != nextIndex else {
        return orderedViewControllers.first
        // Uncommment the line below, remove the line above if you don't want the page control to loop.
        // return nil
    }
    guard orderedViewControllersCount > nextIndex else {
        return nil
    }
    return orderedViewControllers[nextIndex]
    }
   lazy var orderedViewControllers: [UIViewController] = {
    return [self.newVc(viewController: "sbYellow"),
            self.newVc(viewController: "sbRed"),
            self.newVc(viewController: "sbBlue")]
}()
var pageControl = UIPageControl()
override func viewDidLoad() {
    super.viewDidLoad()
    self.dataSource = self
    // This sets up the first view that will show up on our page control
    if let firstViewController = orderedViewControllers.first {
        setViewControllers([firstViewController],
                           direction: .forward,
                           animated: true,
                           completion: nil)
    }
    let pageControl = CustomPageControl(frame: CGRect(x: 100, y: 100, width: 104, height: 40))
    pageControl.numberOfPages = 3
    pageControl.currentPage = 0
    self.view.addSubview(pageControl)
    /*self.delegate = self
    configurePageControl()*/
    // Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
func configurePageControl() {
    // The total number of pages that are available is based on how many available colors we have.
    pageControl = UIPageControl(frame: CGRect(x: 0,y: UIScreen.main.bounds.maxY - 50,width: UIScreen.main.bounds.width,height: 50))
    self.pageControl.numberOfPages = orderedViewControllers.count
    self.pageControl.currentPage = 0
    self.pageControl.tintColor = UIColor.black
    self.pageControl.pageIndicatorTintColor = UIColor.white
    self.pageControl.currentPageIndicatorTintColor = UIColor.black
    self.view.addSubview(pageControl)
}
func newVc(viewController: String) -> UIViewController {
    return UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: viewController)
}
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
    let pageContentViewController = pageViewController.viewControllers![0]
    self.pageControl.currentPage = orderedViewControllers.index(of: pageContentViewController)!
}
}
class CustomPageControl: UIPageControl {
var imageToBeReplacedByDot: UIImage {
return  imageLiteral(resourceName: "av_timer - material")// Image you want to 
replace with dots
}
var circleImage: UIImage {
return  imageLiteral(resourceName: "cancel - material")//Default Image
}
override var numberOfPages: Int {
didSet {
updateDots()
}}
override var currentPage: Int {
didSet {
updateDots()
}}
override func awakeFromNib() {
    super.awakeFromNib()
    self.pageIndicatorTintColor = UIColor.clear
    self.currentPageIndicatorTintColor = UIColor.clear
    self.clipsToBounds = false
}
func updateDots() {
    var i = 0
    for view in self.subviews {
        var imageView = self.imageView(forSubview: view)
        if imageView == nil {
            if i == 0 {
                imageView = UIImageView(image: imageToBeReplacedByDot)
            } else {
                imageView = UIImageView(image: circleImage)
            }
            imageView!.center = view.center
            view.addSubview(imageView!)
            view.clipsToBounds = false
        }
        if i == self.currentPage {
            imageView!.alpha = 1.0
        } else {
            imageView!.alpha = 0.5
        }
        i += 1
    }
}
fileprivate func imageView(forSubview view: UIView) -> UIImageView? {
    var dot: UIImageView?
    if let dotImageView = view as? UIImageView {
        dot = dotImageView
    } else {
        for foundView in view.subviews {
            if let imageView = foundView as? UIImageView {
                dot = imageView
                break
            }
        }
    }
    return dot
}
}

这工作正常，并且改变了图像的点...问题是，如果我滚动，图像不会改变!...我也想将页面控件放置在屏幕的中心顶部..

如何实现这一目标？

屏幕截图:

Answer 1

您可以使用此代码作为引用:

import UIKit

class LocationPageControl: UIPageControl {

let locationArrow: UIImage = UIImage(named: "locationArrow")!
let pageCircle: UIImage = UIImage(named: "pageCircle")!

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

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

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

func updateDots() {
    var i = 0
    for view in self.subviews {
        var imageView = self.imageView(forSubview: view)
        if imageView == nil {
            if i == 0 {
                imageView = UIImageView(image: locationArrow)
            } else {
                imageView = UIImageView(image: pageCircle)
            }
            imageView!.center = view.center
            view.addSubview(imageView!)
            view.clipsToBounds = false
        }
        if i == self.currentPage {
            imageView!.alpha = 1.0
        } else {
            imageView!.alpha = 0.5
        }
        i += 1
    }
}

fileprivate func imageView(forSubview view: UIView) -> UIImageView? {
    var dot: UIImageView?
    if let dotImageView = view as? UIImageView {
        dot = dotImageView
    } else {
        for foundView in view.subviews {
            if let imageView = foundView as? UIImageView {
                dot = imageView
                break
            }
        }
    }
    return dot
}
}

注意:-根据您的需要设置图像