Helper classes to make basic view controller transitions easier

DDHCustomTransition

Helper classes to make basic view controller transitions easier.

Installation

Add CustomTransition.swift to your project.

Usage

1. Create an instance of NavigationControllerDelegate and set to the delegate property of an UINavigationController.
2. Make the view controllers participating in the transition conforming to the TransitionInfoProtocol protocol.
3. There is no step three.

TransitionInfoProtocol

The TransitionInfoProtocol defines two required and one optional methods:

// Return the views which shoud be animated in the transition
func viewsToAnimate() -> [UIView]

// Return a copy of the view which is passed in. The passed in view is one of the views to animate
func copyForView(subView: UIView) -> UIView

/* Optionally return the frames for the views which should be
   animated. This is needed sometimes because for example
   with custom container view contrllers the transitioning code
   can't figure out where on screen the view is actually visible
   when loaded. */
optional func frameForView(subView: UIView) -> CGRect

Let's say you want to animate a image view from the first view controller to the position of the second view controller (see the gif and the demo project). In the first view controller the protocol conformance could look like this:

import UIKit

class ViewController: UIViewController, TransitionInfoProtocol {

    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var label: UILabel!
    
    func viewsToAnimate() -> [UIView] {
        return [imageView, label]
    }
    
    func copyForView(subView: UIView) -> UIView {
        if subView == imageView {
            let imageViewCopy = UIImageView(image: imageView.image)
            imageViewCopy.contentMode = imageView.contentMode
            imageViewCopy.clipsToBounds = true
            return imageViewCopy
        } else if subView == label {
            let labelCopy = UILabel()
            labelCopy.text = label.text
            labelCopy.font = label.font
            labelCopy.backgroundColor = view.backgroundColor
            return labelCopy
        }
        return UIView()
    }
}

In the second view controller it could look like this:

import UIKit

class DetailViewController: UIViewController, TransitionInfoProtocol {

    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var label: UILabel!
    
    func viewsToAnimate() -> [UIView] {
        return [imageView, label]
    }
    
    func copyForView(subView: UIView) -> UIView {
        if subView == imageView {
            let imageViewCopy = UIImageView(image: imageView.image)
            imageViewCopy.contentMode = imageView.contentMode
            imageViewCopy.clipsToBounds = true
            return imageViewCopy
        } else if subView == label {
            let labelCopy = UILabel()
            labelCopy.text = label.text
            labelCopy.font = label.font
            labelCopy.backgroundColor = label.backgroundColor
            return labelCopy
        }
        return UIView()
    }
}

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