Interactive Transition

Check out the Interactive transitions with Hero (Part 1) blog post for a more in-depth tutorial on interactive transition.

General Approach

When implementing a interactive transition, the general approach is to setup a gesture recognizer first. Then do the following 3 things inside the gesture handler:

1. Tell Hero when to start the transition

   Usually happens when gestureRecognizer.state == .began. Begin the transition as normal.

2. Tell Hero to update the animations through out the transition

   Use Hero.shared.update(progress:) & Hero.shared.apply(modifiers:to:) to modify the progress & view states.

3. Tell Hero to end/cancel the transition

   Use Hero.shared.end() or Hero.shared.cancel()

Interactive methods

Hero.shared is the singleton object you can operate with when doing an interactive transition. It has the following 4 methods that are useful for interactive transition:

/**
 Update the progress for the interactive transition.
 - Parameters:
     - progress: the current progress, must be between 0...1
 */
public func update(progress: Double) 

/**
 Finish the interactive transition.
 Will stop the interactive transition and animate from the
 current state to the **end** state
 */
public func end(animate: Bool = true)

/**
 Cancel the interactive transition.
 Will stop the interactive transition and animate from the 
 current state to the **begining** state
 */
public func cancel(animate: Bool = true)

/**
 Override modifiers during an interactive animation.
 
 For example:
 
     Hero.shared.apply([.position(x:50, y:50)], to:view)
 
 will set the view's position to 50, 50
 - Parameters:
     - modifiers: the modifiers to override
     - view: the view to override to
 */
public func apply(modifiers: [HeroModifier], to view: UIView)