Workaround for custom UIViewController animations in landscape?

Question

I have a custom animated UIViewController transition, and it seems that there is a bug in iOS that screws up the layout in landscape orientation. In the main animation method, i

Answer 1

I came across this issue and I just don't feel that the above solutions do this any justice. I propose a solution that doesn't require hacky code and hard coded frames.

UIView has an awesome function to convert a CGRect into the coordinate space of another (namely; +[UIView convertRect:fromView:]). So I want to detail a far simpler way one can achieve this effect in any orientation without any hardcoded values. In this example lets say we want a simple animation that slides a view in from the right of the screen.

So in our animator's animateTransition(:) we could simply perform the following:

Swift

func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
    let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!
    let fromViewController = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!
    
    let toView = toViewController.view
    let fromView = fromViewController.view
    let containerView = transitionContext.containerView()
    
    if(isPresenting) {
        //now we want to slide in from the right
        let startingRect = CGRectOffset(fromView.bounds, CGRectGetWidth(fromView.bounds), 0)
        toView.frame = containerView.convertRect(startingRect, fromView:fromView);
        containerView.addSubview(toView)
        let destinationRect = containerView.convertRect(fromView.bounds, fromView: fromView)
        UIView.animateWithDuration(transitionDuration(transitionContext),
            delay: 0,
            usingSpringWithDamping: 0.7,
            initialSpringVelocity: 0.7,
            options: .BeginFromCurrentState,
            animations: { () -> Void in
                toView.frame = destinationRect
        }, completion: { (complete) -> Void in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
        })
    } else {
        //we want to slide out to the right
        let endingRect = containerView.convertRect(CGRectOffset(fromView.bounds, CGRectGetWidth(fromView.bounds), 0), fromView: fromView)
        UIView.animateWithDuration(transitionDuration(transitionContext),
            delay: 0,
            usingSpringWithDamping: 0.7,
            initialSpringVelocity: 0.7,
            options: .BeginFromCurrentState,
            animations: { () -> Void in
                fromView.frame = endingRect
            }, completion: { (complete) -> Void in
                if !transitionContext.transitionWasCancelled() {
                    fromView.removeFromSuperview()
                }
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
        })
    }
}

Objective-C

UIViewController* toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    
UIView *toView = toViewController.view;
UIView *fromView = fromViewController.view;
UIView *containerView = [transitionContext containerView];

if(self.isPresenting) {
    //now we want to slide in from the right
    CGRect startingRect = CGRectOffset(fromView.bounds, CGRectGetWidth(fromView.bounds), 0);
    toView.frame = [containerView convertRect:startingRect fromView:fromView];
    [containerView addSubview:toView];
    [UIView animateWithDuration:[self transitionDuration:transitionContext]
                     animations:^{
                         toView.frame = [containerView convertRect:fromView.bounds
                                                          fromView:fromView];
                     }
                     completion:^(BOOL finished) {
                         [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
                     }];

} else {
    //we want to slide out to the right
    [UIView animateWithDuration:[self transitionDuration:transitionContext]
                     animations:^{
                         CGRect endingRect = CGRectOffset(fromView.bounds, CGRectGetWidth(fromView.bounds), 0);
                         fromView.frame = [containerView convertRect:endingRect fromView:fromView];
                     }
                     completion:^(BOOL finished) {
                         [fromView removeFromSuperview];
                         [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
                     }];

}

I hope this helps someone else who came here in the same boat (if it does, an up-vote won't hurt :) )