Hide only .supplementary column in UISplitViewController

Question

I've set up a UISplitViewController with style .tripleColumn.

let splitViewController = UISplitViewController(style: .tripleColumn)
preferredDisplayMode = .twoBesideSecondary
preferredSplitBehavior = .tile

For the first menu item "My Stories" it needs three columns. However, for all the other menu items it should only be the primary column (sidebar) and the content visible. The .supplementary column should be hidden.

When clicking on "My stats" for example, the following code hides both the .primary (sidebar) and .supplementary column and only shows "My Stats".

splitViewController?.showDetailViewController(stats, sender: nil)
splitViewController?.hide(.supplementary)

How can I switch to a .twoColumn style and only have the .primary and .secondary column visible?

Answer 1

In a .tripleColumn split view controller, by design, it is impossible for the .primary column to appear without also showing the .supplementary column.

And you cannot change one and the same split view controller from being a .tripleColumn to being a .doubleColumn. I suppose you could just rip the entire split view controller right out of the interface and substitute a different one, but is that really what you want to do? I think it would be better to use the split view controller the way it is designed to be used.

Answer 2

I had similar issue, my solution is pretty "hacky" though. I just change preferred supplementary column width to 1 when I want to hide it. Anything less than 1 causes app to freeze.

func toggleSupplementary(_ isOn: Bool) {
    viewController(for: .supplementary)?.view.alpha = isOn ? 1 : 0
    preferredSupplementaryColumnWidth = isOn ? UISplitViewController.automaticDimension : 1
}

You can also try setting supplementary view controller to nil. That way you will achieve what you wanted.

splitViewController.setViewController(nil, for: .supplementary)

However this is causing crash when your split view controller collapses to compact width and then expands again. Solution with changing column width works in that case too.

Answer 3

The solution is so simple that I hate having lost a day looking for it (and even reconsidering my entire app design).

To hide the supplementary column, set its view to nil. It's that simple.

splitViewController?.setViewController(nil, for: .supplementary)

And when you need it again: set it to a reasonable view!

Note: the show sidebar button is broken when supplementary is nil. I decided to remove the possibility to hide the sidebar all together like in the Music app. To do that, remove "Present Master with Gesture".