页面视图控制器中的子视图控制器无法接收委托调用

我在父级PageViewController内的两个子级视图控制器有问题，另一个子级未收到由一个子级调用的委托。

我的第一个孩子包含按钮，当按下按钮时，另一个孩子中将触发一个委托以暂停计时器。但是，它无法接听电话，并且计时器继续运行。

这是我的PageViewController：

class StartMaplessWorkoutPageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {

    lazy var workoutViewControllers: [UIViewController] = {
        return [self.getNewViewController(viewController: "ButtonsViewController"), self.getNewViewController(viewController: "DisplayMaplessViewController")]
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.dataSource = self
        
        // Saw this from another answer, doesn't do anything that helps (at the moment)
        let buttonsViewController = storyboard?.instantiateViewController(withIdentifier: "ButtonsViewController") as! ButtonsViewController
        let displayMaplessViewController = storyboard?.instantiateViewController(withIdentifier: "DisplayMaplessViewController") as! DisplayMaplessViewController
        
        buttonsViewController.buttonsDelegate = displayMaplessViewController
        
        if let firstViewController = workoutViewControllers.last {
            setViewControllers([firstViewController], direction: .forward, animated: true, completion: nil)
        }
        
        let pageControl = UIPageControl.appearance(whenContainedInInstancesOf: [StartWorkoutPageViewController.self])
        pageControl.currentPageIndicatorTintColor = .orange
        pageControl.pageIndicatorTintColor = .gray
    }
    
    func getNewViewController(viewController: String) -> UIViewController {
        return (storyboard?.instantiateViewController(withIdentifier: viewController))!
    }
    
    // MARK: PageView DataSource
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        guard let viewControllerIndex = workoutViewControllers.firstIndex(of: viewController) else {
            return nil
        }
        
        let previousIndex = viewControllerIndex - 1
        
        guard previousIndex >= 0 else {
            return workoutViewControllers.last
        }
        
        guard workoutViewControllers.count > previousIndex else {
            return nil
        }
        
        return workoutViewControllers[previousIndex]
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        guard let viewControllerIndex = workoutViewControllers.firstIndex(of: viewController) else {
            return nil
        }
        
        let nextIndex = viewControllerIndex + 1
        let workoutViewControllersCount = workoutViewControllers.count
        
        guard workoutViewControllersCount != nextIndex else {
            return workoutViewControllers.first
        }
        
        guard workoutViewControllersCount > nextIndex else {
            return nil
        }
        
        return workoutViewControllers[nextIndex]
    }
    
    func presentationCount(for pageViewController: UIPageViewController) -> Int {
        return workoutViewControllers.count
    }
    
    func presentationIndex(for pageViewController: UIPageViewController) -> Int {
        guard let firstViewController = viewControllers?.first, let firstViewControllerIndex = workoutViewControllers.firstIndex(of: firstViewController) else {
            return 0
        }
        
        return firstViewControllerIndex
    }
}

我的ChildViewController带按钮：

protocol ButtonsViewDelegate: class {
    func onButtonPressed(button: String)
}

class ButtonsViewController: UIViewController {
    
    weak var buttonsDelegate: ButtonsViewDelegate?
    
    var isPaused: Bool = false
    
    @IBOutlet weak var startStopButton: UIButton!
    @IBOutlet weak var optionsButton: UIButton!
    @IBOutlet weak var endButton: UIButton!
    
    @IBAction func startStopButton(_ sender: Any) {
        if isPaused == true {
            buttonsDelegate?.onButtonPressed(button: "Start")
            isPaused = false
        } else {
            buttonsDelegate?.onButtonPressed(button: "Pause")
            isPaused = true
        }
    }
    
    @IBAction func endButton(_ sender: Any) {
        let menu = UIAlertController(title: "End", message: "Are you sure you want to end?", preferredStyle: .actionSheet)
        
        let end = UIAlertAction(title: "End", style: .default, handler: { handler in
            self.buttonsDelegate?.onButtonPressed(button: "End")
        })
        
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel)
        menu.addAction(end)
        menu.addAction(cancelAction)
        
        self.present(menu, animated: true, completion: nil)
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }

}

我的另一个ChildViewController应该接收ButtonsViewDelegate的调用：

import UIKit

class DisplayMaplessViewController: UIViewController, ButtonsViewDelegate {
    
    var timer = Timer()
    var currentTime: TimeInterval = 0.0
    var isCountdown: Bool = false
    var isInterval: Bool = false
    var currentRepeats: Int = 0
    var currentActivity: Int = 0
    var count: Int = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        startIntervalTimer(withTime: 0)
    }

    // Currently not being called
    func onButtonPressed(button: String) {
        switch button {
        case "Start":
            restartIntervalTimer()
        case "Pause":
            pauseIntervalTimer()
        case "End":
            stop()
        default:
            break
        }
    }
    
    func startIntervalTimer(withTime: Double) {
        if withTime != 0 {
            currentTime = withTime
            if isInterval != true {
                isCountdown = true
            }
        }

        timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(intervalTimerUpdate), userInfo: nil, repeats: true)
    }
    
    func pauseIntervalTimer() {
        timer.invalidate()
    }
    
    func restartIntervalTimer() {
        timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(intervalTimerUpdate), userInfo: nil, repeats: true)
    }

    // Currently Not being called
    func stop() {
        timer.invalidate()
        let formatter = DateComponentsFormatter()
        formatter.unitsStyle = .positional
        formatter.allowedUnits = [.hour, .minute, .second]
        formatter.zeroFormattingBehavior = [.pad]
        
        let timeString = formatter.string(from: currentTime)
        
        // save the data etc

        print("Stop is called")
    }
    
    @objc func intervalTimerUpdate() {
        currentTime += 1.0
        print(currentTime)
    }

}

抱歉，此操作已进行了很长时间，已经尝试了一段时间，但真的很生气，它无法正常工作！谢谢！