Question

我有一个ImageViewController，它呈现一个ImageZoomView（目前还没有缩放，但很快就会出现）。当我点击图像时，整个图像会略微向上移动。这不应该发生，图像应该留在它的位置，直到用户滑动或捏住。

ImageViewController位于UIPageViewController内部，允许在视图之间滑动。但是，我唯一的问题是使用ImageViewController（即VideoViewController和PdfViewController都工作正常，并且不会在水龙头上向上移动）

ImageZoomView是一个带有UIImageView的UIScrollView，因为它是子控件。

ImageZoomView：

public class ImageZoomView : UIScrollView
{
    private UIImage _image;
    private UIImageView _imageView;

    public ImageZoomView()
    {
        _imageView = new UIImageView
        {
            ContentMode = UIViewContentMode.ScaleAspectFill
        };

        AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
        ClipsToBounds = true;
        AddSubview(_imageView);
    }

    public int Index { get; set; }

    public override void LayoutSubviews()
    {
        base.LayoutSubviews();
        var imageWidth = Bounds.Width;
        _imageView.Frame = new CGRect(
            Bounds.Left, Bounds.Top,
            imageWidth, imageWidth / _image.Size.Width * _image.Size.Height);

        ContentSize = _imageView.Bounds.Size;
    }

    public void DisplayImage(UIImage image)
    {
        _image = image;
        _imageView.Image = image;
    }
}

ImageViewController：

public class ImageViewController : AssetViewController
{
    private ImageZoomView _imageView;

    public ImageViewController(int index, Media media) : base(index, media) { }

    public override void ViewDidLayoutSubviews()
    {
        base.ViewDidLayoutSubviews();
        _imageView.Frame = View.Bounds;
    }

    public override void LoadView()
    {
        _imageView = new ImageZoomView()
        {
            Index = Index,
            BackgroundColor = UIColor.White,
        };
        _imageView.DisplayImage((_media as LocalMedia<UIImage>).Resource);
        View = _imageView;
    }
}

AssetViewController：

public abstract class AssetViewController : UIPageViewController
{
    protected Media _media;

    public AssetViewController(int index, Media media)
    {
        _media = media;
        Index = index;
        View.BackgroundColor = Globals.ColorDark;
    }

    public int Index { get; set; }

    public Media CurrentMedia { get { return _media; } }
}

Answer 1

引起问题的几件事

所有控制器都是从UIPageViewController派生的。内容控制器不应从UIPageViewController
在ImageViewController中，代码View = _imageView;将主控制器视图替换为ScrollView。我建议使用AddSubview(_imageView);我看到这个错误的动作不是滚动视图，而是以某种方式查看整个控制器。
经常调用LayoutSubviews并且一直计算同样的事情，因为图像大小和滚动边界都没有变化。

以下建议的改进。

ImageViewController是PageViewController内的内容控制器，ImageZoomView是ImageViewController里面的滚动视图

PageViewController

public partial class PageViewController : UIPageViewController
{
    public PageViewController(IntPtr handle) : base(handle)
    {
    }

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();

        List<ImageViewController> pages = new List<ImageViewController>();
        UIStoryboard board = UIStoryboard.FromName("Main", null);

        for (int i = 0; i < 3; i++)
        {
            ImageViewController ctrl = (ImageViewController)board.InstantiateViewController("imageControllerStoryboardID");
            ctrl.Index = i;
            pages.Add(ctrl);
        }
        DataSource = new PageDataSource(pages);
        View.Frame = View.Bounds;
        //Set the initial content (first page)
        SetViewControllers(new UIViewController[] { pages[0] }, UIPageViewControllerNavigationDirection.Forward, false, s => { });
    }


}

public class PageDataSource : UIPageViewControllerDataSource
{
    List<ImageViewController> pages;

    public PageDataSource(List<ImageViewController> pages)
    {
        this.pages = pages;
    }

    override public UIViewController GetPreviousViewController(UIPageViewController pageViewController, UIViewController referenceViewController)
    {
        var currentPage = referenceViewController as ImageViewController;
        if (currentPage.Index == 0)
        {
            return pages[pages.Count - 1];
        }
        else
        {
            return pages[currentPage.Index - 1];
        }
    }

    override public UIViewController GetNextViewController(UIPageViewController pageViewController, UIViewController referenceViewController)
    {
        var currentPage = referenceViewController as ImageViewController;
        return pages[(currentPage.Index + 1) % pages.Count];
    }
}

ImageViewController

public partial class ImageViewController : UIViewController
{
    public int Index;
    private ImageZoomView _imageView;

    public ImageViewController (IntPtr handle) : base (handle)
    {
    }

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();

        _imageView = new ImageZoomView(UIImage.FromFile("MergedImage.png"), View.Frame)
        {
            Index = Index,
            BackgroundColor = UIColor.Blue,
        };
        View.AddSubview(_imageView);
    }

}

ImageZoomView

public class ImageZoomView : UIScrollView
{
    private UIImage _image;
    private UIImageView _imageView;

    public ImageZoomView(UIImage image, CGRect frame):base()
    {
        _imageView = new UIImageView
        {
            ContentMode = UIViewContentMode.ScaleAspectFill,
        };

        _image = image;
        _imageView.Image = image;
        Frame=_imageView.Frame = frame;


        AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
        ClipsToBounds = true;
        AddSubview(_imageView);

        ContentSize = new CGSize(Frame.Width, Frame.Width / _image.Size.Width * _image.Size.Height);
        _imageView.Center = new CGPoint(ContentSize.Width / 2, ContentSize.Height / 2);
    }



    public int Index { get; set; }

}

原始样本中仍有一些代码作为未使用的Index字段和private _image变量。可能在将来有用，所以我保留了它们

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1 个答案: