Swift: how to detect if UISplitViewController is currently showing 1 or 2 controllers?

Question

How can I detect if the UISplitViewController is currently just showing 1 view controller or it's in dual-pane with 2 views controllers shown side-by-side?

Answer 1

The split view controller reflects the actual display mode in the displayMode property:

AllVisible: The primary and secondary UIViewControllers are displayed side-by-side.

PrimaryHidden: The primary UISplitViewController is hidden.

PrimaryOverlay: The primary UISplitViewController overlays the secondary, which is partially visible.

When the isCollapsed property is true, the value of displayMode property is ignored. A collapsed split view interface contains only one view controller so the display mode is superfluous.

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Resume: To find out the detailed situation on screen use isCollapsed property and (if isCollapsed = false) displayMode property.