UIKit · class
UIHingeInteraction
Reports iPhone Duo's hinge angle and state. Apple is explicit that this is for interaction and effects, never for layout decisions.
The hinge angle, as a value you can observe. UIHingeInteraction in UIKit,
onHingeChange in SwiftUI.
The states
Closed, partially open, and fully open — alongside the angle itself.
The rule that matters more than the API
Do not lay out from this. Apple’s guidance is that the angle drives interaction and effects, not frames. It is the most important thing to know about this symbol and the reason it is a polish item rather than a blocker.
Layout that follows the angle jitters, because the angle is continuous and layout is not. What you actually wanted is almost always one of:
UIArrangementViewControllerfor placing two views across poses,UIViewReservedRegionfor staying clear of the fold,- size classes for everything else.
What it is genuinely good for
A camera app dimming a preview as the device closes. A media app pausing at a shallow angle. A game using the pose as an input. Things where the angle is the feature rather than a proxy for screen shape.
Doing the work
This page describes the symbol. For the task and its priority, see use hinge angle for interaction, never for layout.