使用 UIPageViewController 将 PageCurl 转换为滚动

Question

我想在视图之间更改我的动画。 目前我有 PageCurl，但我想要像 Snapchat 这样的滚动动画。

我无法使用var transitionStyle: UIPageViewControllerTransitionStyle { get }

我的ViewController:

import UIKit

class ViewController: UIPageViewController, UIPageViewControllerDataSource{

    let pageViewController = UIPageViewController(transitionStyle: .Scroll, navigationOrientation: .Horizontal, options: nil)
    var messagesViewController : MessagesViewController!
    var searchViewController : SearchViewController!
    var friendsViewController : FriendsViewController!

    override func viewDidLoad() {
        super.viewDidLoad()

        // set UIPageViewControllerDataSource
        self.dataSource = self

        // Reference all of the view controllers on the storyboard
        self.messagesViewController = self.storyboard?.instantiateViewControllerWithIdentifier("messagesViewController") as? MessagesViewController
        self.messagesViewController.title = "Messages"

        self.searchViewController = self.storyboard?.instantiateViewControllerWithIdentifier("searchViewController") as? SearchViewController
        self.searchViewController.title = "Search"

        self.friendsViewController = self.storyboard?.instantiateViewControllerWithIdentifier("friendsViewController") as? FriendsViewController
        self.friendsViewController.title = "Friends"

        // Set starting view controllers
        var startingViewControllers : NSArray = [self.searchViewController]
        self.setViewControllers(startingViewControllers, direction: .Forward, animated: false, completion: nil)
    }


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

        switch viewController.title! {
        case "Messages":
            return nil
        case "Search":
            return messagesViewController
        case "Friends":
            return searchViewController
        default:
            return nil
        }
    }

    // pink green blue

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

        switch viewController.title! {
        case "Messages":
            return searchViewController
        case "Search":
            return friendsViewController
        case "Friends":
            return nil
        default:
            return nil

        }
    }

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

}

Answer 1

来自Apple Docs：

"The value of this property is set when the page view controller is initialized, and cannot be changed."

您必须在初始化时指定过渡样式。如果你在代码中这样做，你将需要类似的东西：

let pageViewController = ViewController(transitionStyle: .Scroll, navigationOrientation: .Horizontal, options: nil)

（因为 ViewController 是 UIPageViewController 的子类）

如果您在故事板中设置页面视图控制器，请在属性检查器中修改过渡样式：

Answer 2

如果你需要使用storyboard并且仍然需要在代码中设置过渡样式你可以在Class继承UIPageViewController的时候使用这个技巧。诀窍在于，在带有编码器的 init 中，您调用 super.init() ，它采用这样的过渡样式

class ViewController: UIPageViewController {

    required init?(coder: NSCoder) {
        super.init(transitionStyle: Configs.transitionStyle, navigationOrientation: .horizontal, options: nil)
    }
}