iosuikitgestureundonsundomanager

iOS 13 Undo/Redo Gestures with UIDocument and a UICollectionViewController

Is it possible to opt into iOS 13's 3-finger undo/redo gestures for a whole UICollectionViewController (or UIViewController/UITableViewController)?

I have a UIDocument which is tracking changes via it's undoManager and I currently call undo/redo on this. However I would like to opt in to allow 3-finger swipes/3-finger double tap/command + z to allow undo to be called and show the new overlay that text views pop-up when you undo/redo.

I've tried setting editingInteractionConfiguration to default on my view controller, which didn't seem to do anything.

Is this possible?

Solution

  • There are two steps that I needed to do here to make this work. The first was to return my document's undo manager as the view controller's undo manager with the following:

    override var undoManager: UndoManager? { return document.undoManager }

    The second was to make the view controller become the first responder, as advised in NSHipster's NSUndoManager article in the section about responding to the older shake gesture:

    override var canBecomeFirstResponder: Bool { true }

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    becomeFirstResponder()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    resignFirstResponder()
}

    I'm still looking for additional code to ensure that the view controller regains it's first responder status after presenting an alert controller containing a text field, but that is realistically a different issue.