Cocoa Swift: Subview not resizing with superview

Question

I'm adding a subview(NSView), here is my code:

override func viewDidAppear() {
    self.view.needsDisplay = true
    let newView = NSView()
    newView.autoresizesSubviews = true
    newView.frame = view.bounds
    newView.wantsLayer = true
    newView.layer?.backgroundColor = NSColor.green.cgColor
    view.addSubview(newView)
}

And it works fine

But when I resize the window the subview is not resizing.

Any of you knows why or how can make the subview resize with superview?

I'll really appreciate your help

you may need to set the autolayout bounds or create a function to update the subview bounds in `viewDidLayoutSubviews` — jessi, Apr 26 '19 at 21:35
If you are using the Interface builder, set constraints between the subview and the newview to be the same (you can do this by anchoring the edges or by anchoring the h and w). Programmatically, I won't reinvent the wheel here - see examples from this SO https://stackoverflow.com/questions/26180822/how-to-add-constraints-programmatically-using-swift — jessi, Apr 26 '19 at 21:42
@jessi those examples in the link you mention is just adding constraints but doesn't help if the super view is been resize — user2924482, Apr 27 '19 at 00:27
I don't understand. As long as the view constraints are related to the superview constraints and you call layoutifneeded, any changes in the superview should cascade to its subview(s) — jessi, Apr 27 '19 at 01:27

score 6 · Accepted Answer · answered Apr 29 '19 at 17:28

You set view.autoresizesSubviews to true, which tells view to resize each of its subviews. But you also have to specify how you want each subview to be resized. You do that by setting the subview's autoresizingMask. Since you want the subview's frame to continue to match the superview's bounds, you want the subview's width and height to be flexible, and you want its X and Y margins to be fixed (at zero). Thus:

override func viewDidAppear() {
    self.view.needsDisplay = true
    let newView = NSView()

    // The following line had no effect on the layout of newView in view,
    // so I have commented it out.
    // newView.autoresizesSubviews = true

    newView.frame = view.bounds

    // The following line tells view to resize newView so that newView.frame
    // stays equal to view.bounds.
    newView.autoresizingMask = [.width, .height]

    newView.wantsLayer = true
    newView.layer?.backgroundColor = NSColor.green.cgColor
    view.addSubview(newView)
}

score 1 · Answer 2 · answered Apr 29 '19 at 16:20

1

I found a fix for this issue:

override func viewWillLayout() {
        super.viewWillLayout()
        newView.frame = view.bounds

    }

answered Apr 29 '19 at 16:20

user2924482

8,380
23
89
173

Cocoa Swift: Subview not resizing with superview

2 Answers2