Setting minimum width of NSSplitViews

Question

I'm having a heck of a time setting up a simple split view. The first split view is collapsed. I need to set a minimum width for it. Everything I see online (scarce for NSSplitViewController/NSSplitView) is for Objective-C, puts everything in the app delegate, and uses XIBs.

Here's the scenario: Window Controller with a segue to a SplitView Controller, which has two split views (2 view controllers).

Which object needs to have the NSSplitViewDelegate?

EDIT: Adding code snippet: For example, I have this:

import Cocoa

class ViewController: NSSplitViewController, NSSplitViewDelegate {


    @IBOutlet weak var pdlSplitView: NSSplitView!

    override func viewDidLoad() {
        super.viewDidLoad()

        }
    override func splitView(splitView: NSSplitView, constrainMinCoordinate proposedMinimumPosition: CGFloat, ofSubviewAt dividerIndex: Int) -> CGFloat {
        return proposedMinimumPosition + 200
    }

}

Is there more that I'm missing?

Thanks

UPDATE

Based on comments below, I've made a change, but now I get a sigAbort on the class definition for the AppDelegate. Full code

ViewController:

import Cocoa

class ViewController: NSSplitViewController, NSSplitViewDelegate {


    @IBOutlet weak var pdlSplitView: NSSplitView!

    let publicDataListings : PDL = PDL()


    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.pdlSplitView.delegate = self

    }

    override func splitView(splitView: NSSplitView, constrainMinCoordinate proposedMinimumPosition: CGFloat, ofSubviewAt dividerIndex: Int) -> CGFloat {
    return proposedMinimumPosition + 200
    }

}

SidebarViewController:

import Cocoa

class SidebarViewController: NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do view setup here.
    }


}

DatasetViewController:

import Cocoa

class DatasetViewController: NSViewController, NSSplitViewDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do view setup here.
    }

}

Update I took away my custom NSSplitViewController class and created two NSSplitView classes, one with the constraint method. Now, I see both subviews, but they're far smaller than they should be:

Is there anyone at all that has done this with Swift and Storyboards?

Answer 1

No coding is required to set a minimum width in a storyboard with auto layout for a NSSplitViewController/NSSplitView.

Select the CustomView that you require a minimum width for (e.g. 200), and add a width constraint set to the required value which will add a "Equal" constraint (e.g. Custom View.Width equals 200).

Next locate that new constraint and change the constraint relation to "Greater Than or Equal" (e.g. so you now have width ≥ 200).

You now have a minimum width in an NSSplitView. You can then use the Priority field to resolve any conflicts with any other auto layout constraints.

Answer 2

These values are not exposed in the storyboard, which is a great shame, but NSSplitViewItem has minimumThickness and maximumThickness properties which you can use. (This overrides the holding priority, so if you set minimumThickness for one splitViewItem, the other one(s) will now shrink into nothing if you make the window small enough.)

There is also automaticMaximumThickness (I cannot work out how this interacts with the other values) and preferredThicknessFraction which had no effect when I played with it under 10.13.

Answer 3

1. Set NSSplitViewController as delegate of NSSplitView (the split view you want to constrain). In your case it should be - in xib hook the delegate outlet of the NSSplitView to file owner (I guess the file owner is NSSplitViewController subclass)

2. Implement

   - (CGFloat)splitView:(NSSplitView *)splitView constrainMinCoordinate:(CGFloat)proposedMin ofSubviewAt:(NSInteger)dividerIndex { ... }
   

in NSSplitViewController

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/NSSplitViewDelegate_Protocol/index.html#//apple_ref/occ/intfm/NSSplitViewDelegate/splitView:constrainMinCoordinate:ofSubviewAt: