test.swift:31:9: Ambiguous reference to member 'pageViewController(_:viewControllerBefore
'.
这是我第一次尝试IOS应用，对swift没有经验，很多代码都是从网上借来编辑的。
我正在尝试创建一组幻灯片。我从主着陆页转到另一个运行幻灯片的 View Controller TestVC。登陆页面和幻灯片有效。我可以来回滑动。我现在正在尝试添加一个计时器，以便幻灯片每 5 秒左右自动前进一次。
我认为需要运行的代码是:
pageViewController.setViewControllers(varPageVC, direction: UIPageViewControllerNavigationDirection.forward, animated: true, completion: nil)
我收到一个错误:
test.swift:31:9: Ambiguous reference to member 'pageViewController(_:viewControllerBefore'.
我不知道如何解释这个错误并继续前进。该错误在 test.swift 中触发，其中计时器调用一个尝试推进幻灯片的函数。建议表示赞赏。如果我做错了，请指出正确的方向。
登录页面有一个按钮，用于打开 ViewController testVC。我有 2 个文件，test.swift 和 alphabetItemController.swift。除了登陆页面 ViewController 之外， Storyboard还有一个称为 alphabetPVC 的 PageViewController、一个称为 alphabetVC 的 ViewController 和一个 ViewController调用TestVC。
这里是 alphabetItemController.swift 的代码 ...
import UIKit
class alphabetItemController: UIViewController {
@IBOutlet weak var contentImageView2: UIImageView!
@IBOutlet weak var contentWordPn: UILabel!
var itemIndex: Int = 0
var imageName: String = ""
var wordPN: String = ""
var tTime: Timer!
override func viewDidLoad() {
super.viewDidLoad()
contentImageView2!.image = UIImage(named: imageName)
contentWordPn!.text = wordPN
}
}
这是 test.swift 的代码 ...
import Foundation
import UIKit
class testItemController: UIViewController, UIPageViewControllerDataSource {
var tTime: Timer!
override func viewDidLoad() {
super.viewDidLoad()
createPageViewController()
setupPageControl()
tTime = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(changeSlide), userInfo: nil, repeats: true)
//tTime = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(goToNextPage), userInfo: nil, repeats: true)
}
func changeSlide() {
pageViewController.setViewControllers(varPageVC, direction: UIPageViewControllerNavigationDirection.forward, animated: true, completion: nil)
}
// MARK: - Variables
private var varPageVC: UIPageViewController?
private let contentTextWordPN = ["A", "B", "C", "D", "E"]
private let contentCount = 5 //TODO ADJUST THIS FOR EACH COLLECTION
private func createPageViewController() {
let pageController = self.storyboard!.instantiateViewController(withIdentifier: "alphabetPVC") as! UIPageViewController
pageController.dataSource = self
if contentCount > 0 {
let firstController = getItemController(itemIndex: 0)!
let startingViewControllers = [firstController]
pageController.setViewControllers(startingViewControllers, direction: UIPageViewControllerNavigationDirection.forward, animated: false, completion: nil)
}
varPageVC = pageController
addChildViewController(varPageVC!)
self.view.addSubview(varPageVC!.view)
varPageVC!.didMove(toParentViewController: self)
}
private func setupPageControl() {
let appearance = UIPageControl.appearance()
appearance.pageIndicatorTintColor = UIColor.gray
appearance.currentPageIndicatorTintColor = UIColor.white
appearance.backgroundColor = UIColor.darkGray
}
func pageViewController(_ varPageVC: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
let itemController = viewController as! alphabetItemController
if itemController.itemIndex > 0 {
return getItemController(itemIndex: itemController.itemIndex-1)
}
return nil
}
func pageViewController(_ varPageVC: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
let itemController = viewController as! alphabetItemController
if itemController.itemIndex+1 < contentCount {
return getItemController(itemIndex: itemController.itemIndex+1)
}
return nil
}
private func getItemController(itemIndex: Int) -> alphabetItemController? {
if itemIndex < contentCount {
let pageItemController = self.storyboard!.instantiateViewController(withIdentifier: "alphabetVC") as! alphabetItemController
pageItemController.itemIndex = itemIndex
pageItemController.imageName = "alphabet_" + String(format: "%02d", (itemIndex + 1)) //alphabet_01
pageItemController.wordPN = contentTextWordPN[itemIndex]
return pageItemController
}
return nil
}
func presentationCountForPageViewController(varPageVC: UIPageViewController) -> Int {
return contentCount
}
func presentationIndexForPageViewController(varPageVC: UIPageViewController) -> Int {
return 0
}
func currentControllerIndex() -> Int {
let pageItemController = self.currentController()
if let controller = pageItemController as? alphabetItemController {
return controller.itemIndex
}
return -1
}
func currentController() -> UIViewController? {
if (self.varPageVC?.viewControllers?.count)! > 0 {
return self.varPageVC?.viewControllers![0]
}
return nil
}
}
extension UIPageViewController {
func goToNextPage(animated: Bool = true) {
guard let currentViewController = self.viewControllers?.first else { return }
guard let nextViewController = dataSource?.pageViewController(self, viewControllerAfter: currentViewController) else { return }
setViewControllers([nextViewController], direction: .forward, animated: animated, completion: nil)
}
func goToPreviousPage(animated: Bool = true) {
guard let currentViewController = self.viewControllers?.first else { return }
guard let previousViewController = dataSource?.pageViewController(self, viewControllerBefore: currentViewController) else { return }
setViewControllers([previousViewController], direction: .reverse, animated: animated, completion: nil)
}
}
还有一个扩展UIPageViewController，但是不知道怎么调用goToNextPage函数。
我最终更改了 changeSlide() 函数...我已经在扩展中拥有下一个幻灯片功能，只有调用它的语法让我无法理解...我找到了一些示例在 SO 上并将它们用作引用:
func changeSlide() {
varPageVC?.goToNextPage()
}
关于ios - 以编程方式推进 UIPageViewController - Swift，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45992734/
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