previewInteraction(_:didUpdatePreviewTransition:ended:)
Informs the delegate of the progress through the preview phase of the preview interaction.
Declaration
func previewInteraction(_ previewInteraction: UIPreviewInteraction, didUpdatePreviewTransition transitionProgress: CGFloat, ended: Bool)Parameters
- previewInteraction:
The preview interaction associated with the current user input.
- transitionProgress:
The progress through the preview phase of the transition. A Cgfloat Swift.struct with a value from
0to1. - ended:
A Boolean whose value indicates whether the preview phase of the transition is complete.
Discussion
This method is called repeatedly during the preview phase of the preview interaction. Use the supplied transitionProgress parameter to update the UI to reflect the progress of the interaction. For example, the peek effect in view controller preview transitions progressively blurs everything except the appropriate view.
The ended parameter is false throughout the preview phase and becomes true as the phase is completed. The preview interaction then transitions to the commit phase, so you should use this point to update the UI as required.