iOS 7 - Modal popup with UIViewcontrollerAnimatedTransitioning - ios

Question

i'm trying to present PopUp ViewController with animation, using UIViewcontrollerAnimatedTransitioning. I've created a Modal Segue from TableViewCell to my Viewcontroller
In PopupPresentAnimationController (that implement UIViewcontrollerAnimatedTransitioning) i have
-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
[fromViewController addChildViewController:toViewController];
toViewController.view.frame = fromViewController.view.frame;
[fromViewController.view addSubview:toViewController.view];
[toViewController didMoveToParentViewController:fromViewController];
NSTimeInterval duration = [self transitionDuration:transitionContext];
[UIView animateWithDuration:duration delay:0.0 usingSpringWithDamping:0.6 initialSpringVelocity:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
fromViewController.view.alpha = 0.5;
} completion:^(BOOL finished) {
fromViewController.view.alpha = 1.0;
[transitionContext completeTransition:YES];
}];
}
The PopUpViewController have a background black with 50% opacity and, when it appear all "works" but after animation end, the screen become black.
UPDATE 1:
UIViewController *fromViewController =[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *container = [transitionContext containerView];
CGRect initialFrame = toViewController.view.frame;
initialFrame.origin.y = toViewController.view.frame.size.height;
toViewController.view.frame = initialFrame;
[container insertSubview:toViewController.view aboveSubview:fromViewController.view];
NSTimeInterval duration = [self transitionDuration:transitionContext];
[UIView animateWithDuration:duration delay:0 options:0 animations:^{
CGRect newFrame = toViewController.view.frame;
newFrame.origin.y = 0;
toViewController.view.frame = newFrame;
} completion:^(BOOL finished) {
[transitionContext completeTransition:YES];
}];
UPDATE 2
In prepareForSegue i have added the follow line
controller.modalPresentationStyle = UIModalPresentationCustom; // controller is the destination
With this line on, the black is no more black!

Answer 1

The problem you're having is that you are adding your toViewController to the fromViewController. When the animation ends, the toViewController is removed and in turn, so is your fromViewController. The proper way to handle this is to use the container view provided by the context:
UIView *container = [transitionContext containerView];
This is an example of how to do a popup transition:
-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *container = [transitionContext containerView];
if (!self.beingDismissed) {
//Make controller hidden so it can slide in
CGRect initialFrame = toViewController.view.frame;
initialFrame.origin.y = toViewController.view.frame.size.height;
toViewController.view.frame = initialFrame;
[container insertSubview:toViewController.view aboveSubview:fromViewController.view];
}
[UIView animateKeyframesWithDuration:0.5 delay:0 options:0 animations:^{
if (!self.beingDismissed) {
//Show view controller
CGRect newFrame = toViewController.view.frame;
newFrame.origin.y = 0;
toViewController.view.frame = newFrame;
} else {
//Hide view controller
CGRect newFrame = fromViewController.view.frame;
newFrame.origin.y = fromViewController.view.frame.size.height;
fromViewController.view.frame = newFrame;
}
} completion:^(BOOL finished) {
[transitionContext completeTransition:finished];
}];
}