init(_:trigger:content:animation:)
Cycles through a sequence of phases in response to changes in a specified value, animating updates to a view on each phase change.
Declaration
init(_ phases: some Sequence<Phase>, trigger: some Equatable, @ViewBuilder content: @escaping (Phase) -> Content, animation: @escaping (Phase) -> Animation? = { _ in .default })Parameters
- phases:
The sequence of phases to cycle through. Ensure that the sequence isn’t empty. If it is, SwiftUI logs a runtime warning and also returns a visual warning as the output view.
- trigger:
A value whose changes cause the animator to use the next phase.
- content:
A view builder closure that takes the current phase as an input. Return a view that’s based on the phase input.
- animation:
A closure that takes the current phase as input. Return the animation to use when transitioning to the next phase. If you return
nil, the transition doesn’t animate. If you don’t set this parameter, SwiftUI uses a default animation.
Discussion
When the phase animator first appears, this initializer renders the content closure using the first phase as input to the closure. When the value of the trigger input changes, the animator reevaluates the content closure using the value from the second phase and animates the change. This procedure repeats with each successive phase until reaching the last phase, at which point the animator loops back to the first phase.