Chapter 8: Animating with SwiftUI
SwiftUI has introduced not only a new way of describing UI elements and components but also a new way of implementing animations. In the case of animations, an even more complex change of thinking is needed. Though the layout concept is inherently declarative, the animation concept is inherently imperative.
When creating an animation in UIKit, for example, it is normal to describe it as a series of steps: when this happens, do that animation for one second, then another animation for two seconds.
Animation in the SwiftUI way requires us to define three parts:
- A trigger: An event that happens, such as a button click, a slider, a gesture, and so on
- A change of data: A change of an
@Statevariable, such as a Boolean flag - A change of UI: A change of something that is represented visually following the change of data – for example, a vertical or horizontal offset, or the size of a component that has one value when the flag is...
