UIViewController Animated Transitioning fails in iOS8 - ios

Question

I've got a custom UIViewController transition -- in iOS7, it works perfectly fine.
However, when run on iOS 8, I'm experiencing issues. Specifically, when the presented view controller is dismissed, the original view controller's view disappears entirely - leaving me with a completely blank screen. Here is my code:
#implementation DDCardTransition
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext {
return 0.5f;
}
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext {
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
CGRect endFrame = self.destinationFrame;
if (self.presenting) {
fromViewController.view.userInteractionEnabled = NO;
toViewController.view.layer.cornerRadius = 6.0f;
UIView *tintAdjustmentView = [UIView new];
tintAdjustmentView.frame = fromViewController.view.frame;
tintAdjustmentView.backgroundColor = [UIColor blackColor];
tintAdjustmentView.alpha = 0.f;
[transitionContext.containerView addSubview:fromViewController.view];
[transitionContext.containerView addSubview:tintAdjustmentView];
[transitionContext.containerView addSubview:toViewController.view];
CGRect startFrame = endFrame;
startFrame.origin.y += [UIScreen mainScreen].bounds.size.height;
toViewController.view.frame = startFrame;
[CATransaction begin];
[CATransaction setCompletionBlock:^{
[transitionContext completeTransition:YES];
}];
CABasicAnimation *frameAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
frameAnimation.timingFunction = [CAMediaTimingFunction functionWithControlPoints:0.1f :0.8f :0.0 :1.0];
frameAnimation.duration = [self transitionDuration:transitionContext];
frameAnimation.fromValue = [NSValue valueWithCGPoint:CGPointMake(CGRectGetMidX(startFrame), CGRectGetMidY(startFrame))];
frameAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(CGRectGetMidX(endFrame), CGRectGetMidY(endFrame))];
toViewController.view.layer.position = [frameAnimation.toValue CGPointValue];
[toViewController.view.layer addAnimation:frameAnimation forKey:#"position"];
CABasicAnimation *opacityAnimation = [CABasicAnimation animationWithKeyPath:#"opacity"];
opacityAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
opacityAnimation.duration = 0.3f;
opacityAnimation.fromValue = #(0.f);
opacityAnimation.toValue = #(0.5f);
tintAdjustmentView.layer.opacity = [opacityAnimation.toValue floatValue];
[tintAdjustmentView.layer addAnimation:opacityAnimation forKey:#"opacity"];
[CATransaction commit];
}
else {
toViewController.view.userInteractionEnabled = YES;
UIView *tintAdjustmentView = [UIView new];
tintAdjustmentView.frame = toViewController.view.frame;
tintAdjustmentView.backgroundColor = [UIColor blackColor];
tintAdjustmentView.alpha = 0.5f;
[transitionContext.containerView addSubview:toViewController.view];
[transitionContext.containerView addSubview:tintAdjustmentView];
[transitionContext.containerView addSubview:fromViewController.view];
endFrame.origin.y += [UIScreen mainScreen].bounds.size.height;
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
fromViewController.view.frame = endFrame;
tintAdjustmentView.alpha = 0.f;
} completion:^(BOOL finished) {
[transitionContext completeTransition:YES];
}];
}
}
#end
Any idea why this no longer works in iOS8?
Thanks!

Answer 1

the following code work fine in xcode GM:
func animateTransition(transitionContext: UIViewControllerContextTransitioning!) {
let fromViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)
let fromViewControllerView = transitionContext.viewForKey(UITransitionContextFromViewKey)
let containerView = transitionContext.containerView()
fromViewControllerView?.frame = transitionContext.finalFrameForViewController(fromViewController!)
fromViewControllerView?.frame.origin.y = containerView.bounds.height
containerView.addSubview(fromViewControllerView!)
UIView.animateWithDuration(transitionDuration(transitionContext),
delay: 0.0,
options: .AllowUserInteraction,
animations: {
fromViewControllerView!.center.y = containerView.bounds.size.height/2
},
completion: { (completed: Bool) -> Void in
transitionContext.completeTransition(completed)
}
)
}