Transitionz

Collection of transitions for UIKit

This project was created to demonstrate how to create and use different transition effects.

How to use

Copy the content of the Swappers folder to your project. -- Perhaps I'll figure out how to make this into a proper library in the future, but now this isn't a concern. Just copying the files is easy enough.

Subclass TraNavigationController, then set the transition effect you wish to use.

You can set the regular transition effect, which will be used in all transitions:

transitionController.regularAnimationType = "slide.up"

This only needs to be set once. The best place to do it is probably in the viewDidLoad method.

Or you can set only the next transition -- after which the regular animation will be used.

transitionController.nextAnimationType = "slide.inFrom.topRight"

The best place to change the next transition is in the pushViewController method.

override func pushViewController(_ viewController: UIViewController, animated: Bool)
{
  transitionController.nextAnimationType = "pushAndFade.forward"
  super.pushViewController(viewController, animated: animated)
}

Don't forget to call super.pushViewController(...).

If no transition effect is set, the default one (Apple's default) is used.

The default transitions effects are:

• nil (Apple's default
• slide.up
• slide.down
• slide.inFrom.topRight
• slide.outTo.topRight
• slide.inFrom.bottomRight
• slide.outTo.bottomRight
• slide.inFrom.bottomLeft
• slide.outTo.bottomLeft
• slide.inFrom.topLeft
• slide.outTo.topLeft
• pushAndFade.forward
• pushAndFade.backward

Each of the transitions above has a reverse transition associated, so that, when the view is poped out, the animation occurs in the reverse direction.

Adding your own transition animations

The first thin you need to do is implement a class that subclasses NSObject and conforms to protocol UIViewControllerAnimatedTransitioning.

class FancyTransition: NSObject, UIViewControllerAnimatedTransitioning
{
  func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval
  { ... }
  
  func animateTransition(using transitionContext: UIViewControllerContextTransitioning)
  { ... }
}

In transitionDuration(...) you just need to return the duration of the animation in seconds. TimeInterval is a typealias for Double.

In animateTransition(...) you'll implement the animation itself. Check the code if you're not sure how to do this.

After that, you need to register your new animation with the Transition Controller. Upon registering a transition animation, you need to provide four things, the transition animation and its reverse, so the system knows what to do when you go back, and one unique identifier for each.

Notice that, when passing the transition object, we actually pass a closure that returns the transition. This way, you can have different durations for each transition, even if they are the same type.

transitionController.register(
    transitionName: "slide.up",
    for: { duration in return VerticalSlideTransition(duration: duration, upwards: true) },
    oppositeName: "slide.down",
    for: { duration in return VerticalSlideTransition(duration: duration, upwards: false) })

After this, you're good to go. You can use your new transition animation just like any other.