c# - Xamarin iOS - 交互式滑动

Question

我正在尝试像所有知名人士一样在我的 Xamarin iOS 应用程序中实现滑动。我找到了simple example用 Swift 编写，但我被第二个代码区域困住了。

class MyViewController: UIViewController, UINavigationControllerDelegate  {

    override func awakeFromNib() {
        super.awakeFromNib()
        self.navigationController?.delegate = self
    }

    func navigationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return SimpleAnimationController()
    }
} 

问题是，在 C# 中，一个类只能继承一个类或多个接口(interface)。另外我也不知道函数 func navigationController 正在做什么。

那么我该如何翻译代码片段呢？

感谢您的帮助!

[编辑 1]

所以我现在像这样实现该类:

public class MyFadeTransition : UIPercentDrivenInteractiveTransition, IUIViewControllerAnimatedTransitioning
{
    private UIViewController TransitioningController;

    public MyFadeTransition(UIViewController transitioningController)
    {
        TransitioningController = transitioningController;
        TransitioningController.View.AddGestureRecognizer(new UIPanGestureRecognizer(DidPan));
    }

    void IUIViewControllerAnimatedTransitioning.AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
    {
        var fromViewController = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);

        var toViewController = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);
        transitionContext.ContainerView.AddSubview(toViewController.View);

        toViewController.View.Alpha = 0.0f;

        UIView.Animate(0.35, () =>
        {
            toViewController.View.Alpha = 1.0f;
            Debug.WriteLine("Custom Transitioning");

        }, () =>
        {
            transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled);
            Debug.WriteLine("Custom Transitioning Done");

        });
    }

    double IUIViewControllerAnimatedTransitioning.TransitionDuration(IUIViewControllerContextTransitioning transitionContext)
    {
        return 0.35;
    }

    public void DidPan(UIPanGestureRecognizer gesture)
    {
        var point = gesture.LocationInView(TransitioningController.View);
        double percent = Math.Max(Math.Min((point.X / 300), 0.99), 0.0f);

        Debug.WriteLine(string.Format("Point: {0} | Percent: {1}", point, percent));

        switch (gesture.State)
        {
            case UIGestureRecognizerState.Began:
                // this.UsingGesture = true
                this.TransitioningController.NavigationController?.PopViewController(true);
                break;
            case UIGestureRecognizerState.Changed:
                UpdateInteractiveTransition((System.nfloat)percent);
                break;
            case UIGestureRecognizerState.Ended:
            case UIGestureRecognizerState.Cancelled:
                if (percent > 0.5)
                {
                    Debug.WriteLine("Finishing Transition");
                    this.FinishInteractiveTransition();
                }
                else
                {
                    Debug.WriteLine("Cancelling Transition");
                    this.CancelInteractiveTransition();
                }
                break;
            default:
                Debug.WriteLine("Unhandled Transition state");
                break;
        }
    }
}

现在 ViewController 正在发生转换，但如果用户仅滑动一些像素，它们也会发生转换。知道这里发生了什么吗？

Answer 1

在 Xamarin.iOS 中，您有一个等效的界面:

IUINavigationControllerDelegate

您可以实现任意数量的接口(interface)。

你可以找到吧here

Xamarin 翻译为

public class MyViewController : UIViewController, IUINavigationControllerDelegate
{

    public override void AwakeFromNib()
    {
        base.AwakeFromNib();
        NavigationController.Delegate = this;
    }

    [Export("navigationController:animationControllerForOperation:fromViewController:toViewController:")]
    public IUIViewControllerAnimatedTransitioning GetAnimationControllerForOperation(UINavigationController navigationController, UINavigationControllerOperation operation, UIViewController fromViewController, UIViewController toViewController)
    {
        return new SimpleAnimationController();
    }
}