[英]How do I implement transitionCompleted of the UIPageViewController delegate in Swift?
如您所見,有兩個UIViewControllers
(其中一個稱為ProView
,充當其他UIViewController
的容器和一個UIPageViewController
。
import UIKit
class ProView: UIViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
var pageViewController: UIPageViewController?
let characterImages = ["character1", "character2"]
override func viewDidLoad() {
super.viewDidLoad()
createPageViewController()
setupPageControl()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController ProView: UIViewController) -> UIViewController? {
let itemController = ProView as PageItemController
if itemController.itemIndex+1 < characterImages.count {
return getItemController(itemController.itemIndex+1)
}
return nil
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerBeforeViewController ProView: UIViewController) -> UIViewController? {
let itemController = ProView as PageItemController
if itemController.itemIndex > 0 {
return getItemController(itemController.itemIndex-1)
}
return nil
}
private func getItemController(itemIndex: Int) -> PageItemController? {
if itemIndex < characterImages.count {
let pageItemController = self.storyboard!.instantiateViewControllerWithIdentifier("ItemController") as PageItemController
pageItemController.itemIndex = itemIndex
pageItemController.imageName = characterImages[itemIndex]
return pageItemController
}
return nil
}
func createPageViewController() {
let pageController = self.storyboard!.instantiateViewControllerWithIdentifier("PageController") as UIPageViewController
pageController.dataSource = self
if characterImages.count > 0 {
let firstController = getItemController(0)!
let startingViewControllers: NSArray = [firstController]
pageController.setViewControllers(startingViewControllers, direction: UIPageViewControllerNavigationDirection.Forward, animated: false, completion: nil)
}
pageViewController = pageController
addChildViewController(pageViewController!)
self.view.addSubview(pageViewController!.view)
pageViewController?.didMoveToParentViewController(self)
}
func setupPageControl() {
let appearance = UIPageControl.appearance()
appearance.pageIndicatorTintColor = UIColor.grayColor()
appearance.currentPageIndicatorTintColor = UIColor.whiteColor()
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return characterImages.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
return 0
}
}
class PageItemController: UIViewController {
@IBOutlet weak var imageCharacterChoose: UIImageView!
var itemIndex: Int = 0
var imageName: String = "" {
didSet {
if let imageView = imageCharacterChoose {imageCharacterChoose.image = UIImage(named: imageName)
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
imageCharacterChoose!.image = UIImage(named: imageName)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
我想知道用戶是否正確地從一個視圖滑動到另一個視圖。 就此而言,我需要使用transitionCompleted
方法來工作:
func pageViewController(ProView: UIPageViewController,
didFinishAnimating finished: Bool,
previousViewControllers pageViewController: [AnyObject],
transitionCompleted completed: Bool)
{
// If the page did not turn
if (!completed)
{
// You do nothing because whatever page you thought
// the book was on before the gesture started is still the correct page
println("The page number did not change.")
return;
}
// This is where you would know the page number changed and handle it appropriately
println("The page number has changed.")
}
問題是不起作用(控制台輸出不打印任何東西),因為參數可能不正確。 根據Apple Reference,
pageViewController頁面視圖控制器。 previousViewControllers轉換前的視圖控制器。
因此,我使用“ProView”和“pageViewController”更改了參數,但這似乎不起作用。 根據transitionCompleted
方法的代碼,正確的參數是什么? 我需要申報一些東西嗎?
問題是pageViewController:didFinishAnimating:...
是一個委托方法,但是這個類不是頁面視圖控制器的委托。
你有這條線:
pageController.dataSource = self
所以你要設置dataSource
。 但你永遠不會設置delegate
。 設置它:
pageController.delegate = self
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