iOS - Presenting a view controller from a presented view controller changes its height

Question

I've a custom transition between two controller that works close to the iOS mail app, which one stays on top of the other with some implemented scrolling behavior.

If I present a new view controller from the Presented view controller which isn't full screen sized, and then I dismiss this new presented view controller, the previous Presented view controller changes its height and then resizes itself.

I know this might be a little confusing but check the gif example below.

As you can see, If I present this custom image picker and then dismiss it, the view controller which presented it warps to full screen and then resizes to the initial value.

How can I prevent this from happening? I want the ViewController which presents the image picker keeps its height.

After the dismiss you can see the resize happening.

Setting the presenting view controllers size

Since it's a UIViewControllerAnimatedTransitioning I create a custom presentation and the size it's set has it's own identity

class CustomPresentationController: UIPresentationController {

    override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController!) {
        super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
    }

    override var frameOfPresentedViewInContainerView: CGRect {
        let containerBounds = self.containerView?.bounds
        let origin = CGPoint(x: 0.0, y: ((containerBounds?.size.height)! * 0.05))
        let size = CGSize(width: (containerBounds?.size.width)! , height: ((containerBounds?.size.height)! * 0.95))
        // Applies the attributes
        let presentedViewFrame: CGRect = CGRect(origin: origin, size: size)
        return presentedViewFrame
    }

    override func containerViewWillLayoutSubviews() {
        presentedView?.frame = frameOfPresentedViewInContainerView
    }
}

Any hint? thanks

Answer 1

I think that is where the issue is. You are forcing the frame size which is not working out. You should use something like preferredContentSize .

You can simply add this to the viewDidLoad of your CustomPresentationController .

Alternatively you may also try modalPresentationStyle as "Over Current Context"

You can refer very good examples of how you can keep some part of VC as transparent here