在不同的滑动视图之间传递 UIPageViewController 中的数据

Question

我正在处理一个具有 3 个可通过滑动访问的视图的项目。

以下代码实现了我用来处理滑动动作的 PageViewController：

import UIKit

class PageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {

    lazy var orderedViewControllers : [UIViewController] = {
        return [self.newVC(viewController : "ClimaVC"),
            self.newVC(viewController : "WeatherVC"),
            self.newVC(viewController : "ClosetVC")]
    }()

    var myViewControllers = [UIViewController]()

    var currentIndex : Int = 0


    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.

        self.dataSource = self

        setViewControllers([orderedViewControllers[1]],
                           direction: .forward, animated: true, completion: nil)

        self.delegate = self
    }


    func newVC(viewController : String) -> UIViewController {

        return UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: viewController)
    }

    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
            //Return nil to avoid swiping forever.
            return nil
        }

        guard orderedViewControllers.count > previousIndex else {
            return nil
        }

        currentIndex = previousIndex

        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;

        guard orderedViewControllers.count != nextIndex else {
            //return orderedViewControllers.first
            //Return nil to avoid swiping forever.
            return nil
        }

        guard orderedViewControllers.count > nextIndex else {
            return nil
        }

        return orderedViewControllers[nextIndex]
    }
}

主视图控制器是 WeatherVC。在此视图中，时间数据被检索并存储在一个名为 timeOfDay 的整数变量中。

根据timeOfDay的值，显示的背景会有所不同。虽然我能够在 WeatherVC 中使用此变量，但我需要将此变量 timeOfDay 传递给另外两个视图控制器 ClimaVC 和 壁橱VC。

我尝试设置委托协议但失败了，使用 UIPageViewControllerDelegate 提供的不同功能进行了探索，但它没有让我得到任何结果。

非常感谢您对此的帮助，

非常感谢！

Answer 1

并不复杂，只需在pageviewcontroller数据源上赋值即可。

        import UIKit

                    class ClimaViewController: UIViewController{
            var timeOfDayClima: Int = 0

            override func viewDidAppear(_ animated: Bool) {
                super.viewDidAppear(animated)
                print (timeOfDayClima)
            }
        }

        class WeatherViewController: UIViewController{
            var timeOfDayClima: Int = 0


            override func viewDidAppear(_ animated: Bool) {
                super.viewDidAppear(animated)
               timeOfDayClima +=  1
            }
        }

        class ClosetViewController: UIViewController{
            var timeOfDayClima: Int = 0

            override func viewDidAppear(_ animated: Bool) {
                super.viewDidAppear(animated)
                print (timeOfDayClima)
            }
        }
        class PageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {

            lazy var orderedViewControllers : [UIViewController] = {
                return [self.newVC(viewController : "ClimaVC"),
                        self.newVC(viewController : "WeatherVC"),
                        self.newVC(viewController : "ClosetVC")]
            }()

            var myViewControllers = [UIViewController]()

            var currentIndex : Int = 0


            override func viewDidLoad() {
                super.viewDidLoad()

                // Do any additional setup after loading the view.

                self.dataSource = self

                setViewControllers([orderedViewControllers[1]],
                                   direction: .forward, animated: true, completion: nil)

                self.delegate = self


            }


            func newVC(viewController : String) -> UIViewController {

                return UIStoryboard(name: "Second", bundle: nil).instantiateViewController(withIdentifier: viewController)


            }

            func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {

                //Guard = some kind of if statement.
                guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
                    return nil
                }



                let previousIndex = viewControllerIndex - 1;



                guard previousIndex >= 0 else {
                    // return orderedViewControllers.last
                    //Return nil to avoid swiping forever.
                    return nil
                }

                guard orderedViewControllers.count > previousIndex else {
                    return nil
                }

                currentIndex = previousIndex


                if(currentIndex == 0) {
                    (orderedViewControllers.first as! ClimaViewController).timeOfDayClima = (orderedViewControllers[1] as! WeatherViewController).timeOfDayClima
                }

                return orderedViewControllers[previousIndex]

            }

            func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {

                //Guard = some kind of if statement.
                guard let viewControllerIndex = orderedViewControllers.index(of: viewController)
                    else {
                        return nil
                }

                let nextIndex = viewControllerIndex + 1;

                guard orderedViewControllers.count != nextIndex else {
                    //return orderedViewControllers.first
                    //Return nil to avoid swiping forever.
                    return nil
                }

                guard orderedViewControllers.count > nextIndex else {
                    return nil
                }

                currentIndex = nextIndex
                if(currentIndex == orderedViewControllers.count - 1) {
                    (orderedViewControllers.last as! ClosetViewController).timeOfDayClima = (orderedViewControllers[1] as! WeatherViewController).timeOfDayClima
                }


                if(nextIndex == 0) {
                    let secondVC = self.storyboard?.instantiateViewController(withIdentifier: "ClimaVC") as! ClimaViewController
                    secondVC.timeOfDayClima = 1
                }

                return orderedViewControllers[nextIndex]

            }

            override func didReceiveMemoryWarning() {
                super.didReceiveMemoryWarning()
                // Dispose of any resources that can be recreated.
            }


        }

Answer 2

也许您也应该尝试解释在设置委托协议时失败的原因，因为这似乎是您正在寻找的解决方案。我在这里写了一个协议供参考，但您必须根据需要进行更改。

protocol WeatherVCDelegate {
    func changedTime(timeOfDay: Int)
}

这里是棘手的部分。在 WeatherVC 中声明委托时，需要使用委托调用函数将 timeOfDay 中继到其他 WeatherVC。它的工作原理是任何符合委托协议的东西都会被触发使用该函数。

class WeatherVC {
    weak var delegate: WeatherVCDelegate?

func functionName() {
    delegate?.changedTime(timeOfDay: value)
}

现在，当您在 PageViewController 中初始化 weatherVC 时，您需要 PageViewController 符合 weatherVC 委托。

In PageViewController...
weatherVC.delegate = self
extension PageViewController: WeatherVCDelegate {
     ...
}

如果我的回答不够清楚，请阅读有关代表的更多信息 https://medium.com/@jamesrochabrun/implementing-delegates-in-swift-step-by-step-d3211cbac3ef