How to load NSView from Xib with Swift 3

Question

How to load NSView from Xib properly?

My code:

var topLevelArray: NSArray? = nil
let outputValue = AutoreleasingUnsafeMutablePointer<NSArray>(&topLevelArray)

if Bundle.main.loadNibNamed("RadioPlayerView", owner: nil, topLevelObjects: outputValue) {
    let views = outputValue.pointee
    return views.firstObject as! RadioPlayerView
}

topLevelArray = nil
return nil

The problem is "outputValue" is a auto-release pointer, and as soon as I return from the function, the program crash with ACCESS_BAD_ADDRESS

Answer 1

I made an protocol and extension to do this:

import Cocoa

protocol NibLoadable {
    static var nibName: String? { get }
    static func createFromNib(in bundle: Bundle) -> Self?
}

extension NibLoadable where Self: NSView {

    static var nibName: String? {
        return String(describing: Self.self)
    }

    static func createFromNib(in bundle: Bundle = Bundle.main) -> Self? {
        guard let nibName = nibName else { return nil }
        var topLevelArray: NSArray? = nil
        bundle.loadNibNamed(NSNib.Name(nibName), owner: self, topLevelObjects: &topLevelArray)
        guard let results = topLevelArray else { return nil }
        let views = Array<Any>(results).filter { $0 is Self }
        return views.last as? Self
    }
}

Usage:

final class MyView: NSView, NibLoadable {
    // ...
}

// create your xib called MyView.xib

// ... somewhere else:

let myView: MyView? = MyView.createFromNib()