UIPageViewController

如果UIPageViewController 的效果是翻页效果 那么下面的点是不会出现的

import UIKit

class PageViewController: UIPageViewController {

    private lazy var vc1 = storyboard!.instantiateViewController(withIdentifier: "VC1")
    private lazy var vc2 = storyboard!.instantiateViewController(withIdentifier: "VC2")
    private lazy var vc3 = storyboard!.instantiateViewController(withIdentifier: "VC3")
    private var pages: [UIViewController] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        dataSource = self
        
        pages = [vc1,vc2,vc3]
        //设置首页
        setViewControllers([vc1], direction: .forward, animated: true, completion: nil)
    }
    
}

extension PageViewController: UIPageViewControllerDataSource {
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        let currentIndex = pages.firstIndex(of: viewController)!
        return currentIndex ==  0 ? pages[pages.count - 1] : pages[currentIndex - 1]
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        let currentIndex = pages.firstIndex(of: viewController)!
        return currentIndex == pages.count - 1 ? pages[0] : pages[currentIndex + 1]
    }
    
    //显示下面的点
    func presentationCount(for pageViewController: UIPageViewController) -> Int {
        return pages.count
    }
    
    func presentationIndex(for pageViewController: UIPageViewController) -> Int {
        return 0
    }
}

不使用PageController的点 使用PageControl

class PageViewController: UIPageViewController {

    private lazy var vc1 = storyboard!.instantiateViewController(withIdentifier: "VC1")
    private lazy var vc2 = storyboard!.instantiateViewController(withIdentifier: "VC2")
    private lazy var vc3 = storyboard!.instantiateViewController(withIdentifier: "VC3")
    private var pages: [UIViewController] = []
    var pageControl: UIPageControl!
    var pendingIndex = 1

    override func viewDidLoad() {
        super.viewDidLoad()

        dataSource = self
        delegate = self
        pages = [vc1,vc2,vc3]
        //设置首页
        setViewControllers([vc1], direction: .forward, animated: true, completion: nil)
        
        pageControl = UIPageControl(frame: CGRect(x: 0, y: UIScreen.main.bounds.maxY - 100, width: UIScreen.main.bounds.width, height: 50))
        pageControl.numberOfPages = pages.count
//        pageControl.currentPage = 0
        view.addSubview(pageControl)
    }
    
}

extension PageViewController: UIPageViewControllerDataSource {
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        let currentIndex = pages.firstIndex(of: viewController)!
        return currentIndex ==  0 ? pages[pages.count - 1] : pages[currentIndex - 1]
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        let currentIndex = pages.firstIndex(of: viewController)!
        return currentIndex == pages.count - 1 ? pages[0] : pages[currentIndex + 1]
    }
}

extension PageViewController: UIPageViewControllerDelegate {
    
    func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
        
        if completed {
            pageControl.currentPage = pendingIndex
        }
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
        pendingIndex = pages.firstIndex(of: pendingViewControllers[0])!
    }
}