Instance Method

previewInteraction(_:didUpdatePreviewTransition:ended:)

Informs the delegate of the progress through the preview phase of the preview interaction.

Required.

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 with a value from 0 to 1

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.

See Also

Preview Interaction Delegate Methods

func previewInteractionShouldBegin(UIPreviewInteraction) -> Bool

Asks the delegate whether a preview interaction is allowed to begin.

func previewInteraction(UIPreviewInteraction, didUpdateCommitTransition: CGFloat, ended: Bool)

Informs the delegate of the preview interaction's progress through the commit phase.

func previewInteractionDidCancel(UIPreviewInteraction)

Informs the delegate that the specified preview interaction was canceled.

Required.