Swift 3 - UIPageViewController - 不鼓励在分离的视图控制器上呈现视图控制器

Posted 2023-03-13

【中文标题】Swift 3 - UIPageViewController - 不鼓励在分离的视图控制器上呈现视图控制器

【英文标题】：Swift 3 - UIPageViewController - Presenting view controllers on detached view controllers is discouraged

【发布时间】：2017-07-11 14:51:19

【问题描述】：

我正在使用 UIPageViewController 来打开我的应用程序。第三页是我的登录页面。这包含 facebook 登录。当我单击 facebook 登录按钮 时，打开空白页面和 xcode 给我这个输出 “不鼓励在分离的视图控制器上显示视图控制器 。”

当 我不使用 UIPageViewController 时，此按钮有效。所以有我的代码。我该如何解决这个问题？

import UIKit

class MyPageViewController: UIPageViewController, 
UIPageViewControllerDataSource, UIPageViewControllerDelegate 

var pageContainer: UIPageViewController!
// The pages it contains
var pages = [UIViewController]()

// Track the current index
var currentIndex: Int?
private var pendingIndex: Int?

override func viewDidLoad() 
    super.viewDidLoad()
    // Setup the pages
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let page1: UIViewController! = storyboard.instantiateViewController(withIdentifier: "firstVC")
    let page2: UIViewController! = storyboard.instantiateViewController(withIdentifier: "secondVC")
    let page3: UIViewController! = storyboard.instantiateViewController(withIdentifier: "LoginPage")
    pages.append(page1)
    pages.append(page2)
    pages.append(page3)

    pageContainer = UIPageViewController(transitionStyle: .scroll, navigationOrientation: .horizontal, options: nil)
    pageContainer.delegate = self
    pageContainer.dataSource = self
    pageContainer.setViewControllers([page1], direction: UIPageViewControllerNavigationDirection.forward, animated: false, completion: nil)
    // Add it to the view
    view.addSubview(pageContainer.view)



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

    let currentIndex = pages.index(of: viewController)!
    if currentIndex == 0 
        return nil
    
    let previousIndex = abs((currentIndex - 1) % pages.count)
    return pages[previousIndex]


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

    let currentIndex = pages.index(of: viewController)!
    if currentIndex == pages.count-1 
        return nil
    
    let nextIndex = abs((currentIndex + 1) % pages.count)
    return pages[nextIndex]



func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) 
    pendingIndex = pages.index(of: pendingViewControllers.first!)


override func didReceiveMemoryWarning() 
    super.didReceiveMemoryWarning()

我也可以试试这个

let page3: UIViewController! = storyboard.instantiateViewController(withIdentifier: "LoginPage")

到这里

let page3: UIViewController! = storyboard.instantiateViewController(withIdentifier: "LoginPage") as! LoginPage

或者这个

let page3: LoginPage! = storyboard.instantiateViewController(withIdentifier: "LoginPage") as! LoginPage

没用。

【参考方案1】：

为您的LoginPage 控制器创建delegate，该控制器具有通知Facebook 登录按钮按下的功能。像这样的：

protocol LoginPageDelegate: class 
    func loginPageDidPressFacebookButton(_ controller: LoginPage)

现在将 delegate 属性添加到您的 LoginPage 类中

class LoginPage: UIViewController 
    weak var delegate: LoginPageDelegate?

现在你需要在用户按下Facebook login button时通知代理

@IBAction func facebookButtonPressed(button: UIButton) 
    self.delegate?.loginPageDidPressFacebookButton(self)

您不能在MyPageViewController 中订阅此delegate。

首先你需要使它的类符合LoginPageDelegate

 class MyPageViewController: UIPageViewController,
UIPageViewControllerDataSource, UIPageViewControllerDelegate, LoginPageDelegate 

    //MARK: LoginPageDelegate methods

    func loginPageDidPressFacebookButton(_ controller: LoginPage) 
        //present what you need here
    

现在在你给你看之前LoginPage：

let page3: LoginPage! = storyboard.instantiateViewController(withIdentifier: "LoginPage")
    page3.delegate = self

【讨论】：

其实我的 facebook 按钮是自动打开到 web 并且没有任何动作。所以当我尝试你的答案时我会改变它并且它有效！谢谢（：