Documentation - Popover

Popover

Select your xib interface, Drag a button into the view, and change button title to "Show Popover".
Declare popover variable in the controller class.
Define a function called showPopoverAction, Connect button action to it, in where you can write show popover code.

The reference code is implemented as follows:

import Cocoa
class HDPopoverVC: NSViewController {
    
    lazy var popover: HDPopover? = {
        let popover = HDPopover()
        return popover
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do view setup here.
    }
    
    @IBAction func showPopoverAction(_ sender: Any) {
        if let button = sender as? NSButton {
            if let view = button.superview {
                let pointInWindow = view.convert(button.frame, to: nil)
                popover?.show(relativeTo: pointInWindow, of: view, preferredEdge: .minY)
            }
        }
    }
}