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

Answer 1

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)
}