xamarin.ios 使用仅图像代码实现 PageController

Question

我正在开发一个带有 xamarin、只有代码、没有 StoryBoard 或任何设计器的 ios 应用程序。 我需要实现一个包含许多图像并水平滚动的 UiViewController，就像this。

我没有找到适合我的东西。 所以有人有一些建议或一些例子给我看吗？

Answer 1

您似乎需要一个没有情节提要或 .xib 的 UIPageViewController。

你需要 3 个自定义类来实现它。

1. MyPageViewController - 自定义UIPageViewController

   public class MyPageViewController : UIPageViewController
   {
       private List<ContentViewController> pages = new List<ContentViewController>();
   
       public MyPageViewController() : base(UIPageViewControllerTransitionStyle.Scroll, UIPageViewControllerNavigationOrientation.Horizontal)
       {
           View.Frame = UIScreen.MainScreen.Bounds;
   
           pages.Add(new ContentViewController(0,UIColor.Red));
           pages.Add(new ContentViewController(1,UIColor.Green));
           pages.Add(new ContentViewController(2,UIColor.Blue));
   
           DataSource = new PageDataSource(pages);
   
           SetViewControllers(new UIViewController[] { pages [0] as UIViewController }, UIPageViewControllerNavigationDirection.Forward, false, null);
       }
   }
   

2. PageDataSource:

   public class PageDataSource : UIPageViewControllerDataSource
   {
       List<ContentViewController> pages; 
   
       public PageDataSource(List<ContentViewController> pages)
       {
           this.pages = pages;
       }
   
       override public UIViewController GetPreviousViewController(UIPageViewController pageViewController, UIViewController referenceViewController)
       {
           ContentViewController currentPage = referenceViewController as ContentViewController;
           ContentViewController pageToReturn = null;
   
           if (currentPage.Index == 0)
           {
               pageToReturn = pages[pages.Count - 1];
           }
           else
           {
               pageToReturn = pages[currentPage.Index - 1];
           }
   
           // NOTE: If the same view controller is returned, UIPageViewController will break and show black screen
           return pageToReturn != currentPage ? pageToReturn : null; 
       }
   
       override public UIViewController GetNextViewController(UIPageViewController pageViewController, UIViewController referenceViewController)
       {
           ContentViewController currentPage = referenceViewController as ContentViewController;
           ContentViewController pageToReturn = pages[(currentPage.Index + 1) % pages.Count];
   
           return pageToReturn != currentPage ? pageToReturn : null;
       }
   }
   

3. ContentViewController - 自定义UIViewController，只需添加属性Index

   public class ContentViewController : UIViewController
   {
       private int index = -1;
       public int Index
       {
           get
           { 
               return index;
           }
       }
   
       public ContentViewController(int _index, UIColor backColor)
       {
           this.index = _index;
           this.View.Frame = UIScreen.MainScreen.Bounds;
           this.View.BackgroundColor = backColor;
       }
   }
   

最后，覆盖 AppDelegate.cs 中的 FinishedLaunching 方法：

public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
{
    this.Window = new UIWindow(UIScreen.MainScreen.Bounds);
    this.Window.RootViewController = new MyPageViewController();
    this.Window.MakeKeyAndVisible();

    return true;
}

希望对你有帮助。

如果您还有问题，请在此处留下。