ProgressBar with DispatchQueue

You have to create a MacOS playground.

This works in such a playground (note that I had to make a few corrections):

import Dispatch
import Foundation

var comboCount:NSKeyValueObservation?

class viewContr: NSViewController {
    @IBOutlet weak var progressBar: NSProgressIndicator!
//    deinit { comboCount?.invalidate() }
    
    @IBAction func calcStuff(_ sender: NSButton) {
        DispatchQueue.global(qos: .userInitiated).async {
            let combos =  possibleCombos()
            DispatchQueue.main.async {
                for word in combos {
                    word.print0b8()
                }
            }
        }
    }
}

func possibleCombos() -> [Int8] {
    var combos = [Int8] ()
    for a in [0, 1] {
        for b in [0, 1] {
            for c in [0, 1] {
                for d in [0, 1] {
                    combos.append(Int8(d | (c << 1) | (b << 2) | (a << 3)) )
                    comboCount = combos.count/16 as! NSKeyValueObservation
                    // known total combos = 16
                    // How do I pass combos.count out to a progress bar?
                }
            }
        }
    }
    return combos
}

extension Int8 {func print0b8() {print("0b" + pad(string: String(self, radix: 2), toSize: 4))}}

func pad(string : String, toSize: Int) -> String {var padded = string;for _ in 0..<(toSize - string.count) {padded = "0" + padded};return padded}

I tested the following in app

class viewContr: NSViewController {

    var comboCount: Int = 0 // NSKeyValueObservation?
    
    var when = DispatchTime.now()

    @IBOutlet weak var progressBar: NSProgressIndicator!
        //    deinit { comboCount?.invalidate() }
        
    @IBAction func calcStuff(_ sender: NSButton) {
        DispatchQueue.global(qos: .userInitiated).async {[self] in
            let combos =  possibleCombos()
            DispatchQueue.main.asyncAfter(deadline: when) {
                print(combos.count)
                for word in combos {
                    word.print0b8()
                }
            }
        }
    }
    
    func possibleCombos() -> [Int8] {
        var combos = [Int8] ()
        when = DispatchTime.now()
        for a in [0, 1] {
            for b in [0, 1] {
                for c in [0, 1] {
                    for d in [0, 1] {
                        DispatchQueue.global().asyncAfter(deadline: when) {[self] in
                            combos.append(Int8(d | (c << 1) | (b << 2) | (a << 3)) )
                            comboCount = (100 * combos.count) / 16 // as! NSKeyValueObservation
                            DispatchQueue.main.async { [self] in
                                progressBar.doubleValue = Double(comboCount)
                            }
                            // known total combos = 16
                            // How do I pass combos.count out to a progress bar?
                        }
                        when = when + .milliseconds(200)
                    }
                }
            }
        }
        return combos
    }
}

Indicator (determinate) works ok.

There is a problem to fix

                    word.print0b8()

because it has only one item when printing. Some dispatch to adjust. A solution would be to move it inside the possibleCombos()

But now, you should do it with async-await pattern.

I will try this change:

        for d in [0, 1] {
                   combos.append(Int8(d | (c << 1) | (b << 2) | (a << 3)) )
                   comboCount = (100 * combos.count) / 16 // as! NSKeyValueObservation
                    DispatchQueue.global().asyncAfter(deadline: when) {[self] in

maybe there was a way to have remote functions "use" or "pass" messages into or out-of the ViewController

Yes there are several ways:

• by delegation : that's the most appropriate
• by notification: very easy. Just have the otherViewController subscribe to a notification and post one from ViewController. But take care if you need very short response time.
• even with a direct reference of the other viewController inside ViewController (not the cleanest way)

Before detailing,

• what do you mean by  ViewController as it is currently remote ?
• which controller is on screen when you update ?

Claude31, first, thank you for the example of a progress bar with DispatchQueue. I can now advance. I have closed this thread and opened another with this delegation subject, since it is another issue deserving credit.