xamarin.ios使用仅图像代码实现PageController [英] xamarin.ios implement PageController with images only code

问题描述

我正在开发一个带有xamarin的ios应用程序，只有代码，没有StoryBoard或任何设计师。
i需要实现一个包含许多图像的UiViewController，并横向滚动，就像这个。

i'm developing an ios app with xamarin, only code, without StoryBoard, or any designer. i need to implement a UiViewController that contains many images, and scrolls horizontally, just like this.

我找不到适合自己的东西。
所以有人有一些建议或一些例子给我看？

I don't have found anything suitable for me. so someone have some suggestion or some example to show me?

推荐答案

好像你需要一个 UIPageViewController 没有storyboard或.xib。

Seems like you need a UIPageViewController without storyboard or .xib.

您需要3个自定义类来实现它。

You need 3 custom classes to implement it.

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);
    }
}

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;
    }
}

ContentViewController - 自定义 UIViewController ，只需添加属性索引

ContentViewController - A custom UIViewController, just need to add the property 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;
}

希望它可以帮到你。

如果您还有一些问题，请将其保留在此处。

If you still have some questions, just leave it here.

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