How to use UIViewControllerTransitioningDelegate with MvxIosViewPresenter?

Question

I have a view controller A and a view controller B and I want to navigate from A to B (present modally) with a custom transition (UIViewControllerTransitioningDelegate), how would I do it with MvxIosViewPresenter?

Do I need to write a completely custom presenter by myself or is there a way how to do in an elegant way?

Answer 1

it is completely possible to use a custom transition with the MvxIosViewPresenter. All you have to do is to create a custom UIViewControllerTransitioningDelegate and assign it to your ViewController (ViewDidLoad is a good place to do it).

Something like this should do the work:

[MvxModalPresentation(ModalPresentationStyle = UIModalPresentationStyle.OverFullScreen, ModalTransitionStyle = UIModalTransitionStyle.CrossDissolve)]
public partial class ModalView : MvxViewController<ModalViewModel>
{
    public ModalView(IntPtr handle) : base(handle)
    {
    }

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

        TransitioningDelegate = new TransitioningDelegate();
    }
}

public class TransitioningDelegate : UIViewControllerTransitioningDelegate
{
    public override IUIViewControllerAnimatedTransitioning GetAnimationControllerForPresentedController(UIViewController presented, UIViewController presenting, UIViewController source)
    {
        return new CustomTransitionAnimator();
    }
}

public class CustomTransitionAnimator : UIViewControllerAnimatedTransitioning
{
    public override double TransitionDuration(IUIViewControllerContextTransitioning transitionContext)
    {
        return 1.0f;
    }

    public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
    {
        var inView = transitionContext.ContainerView;
        var toVC = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);
        var toView = toVC.View;

        inView.AddSubview(toView);

        var frame = toView.Frame;
        toView.Frame = CGRect.Empty;

        UIView.Animate(TransitionDuration(transitionContext), () =>
        {
            toView.Frame = new CGRect(10, 10, frame.Width - 20, frame.Height - 20);
        }, () =>
        {
            transitionContext.CompleteTransition(true);
        });
    }

}