swiftui-script.swift

#! /usr/bin/swift

//
// - This is just some AppKit boilerplate to launch a window.
//
import AppKit
@available(OSX 10.15, *)
class AppDelegate: NSObject, NSApplicationDelegate {
    let window = NSWindow()
    let windowDelegate = WindowDelegate()
    func applicationDidFinishLaunching(_ notification: Notification) {
        let contentSize = NSSize(width:800, height:600)
        window.setContentSize(contentSize)
        window.styleMask = [.titled, .closable, .miniaturizable, .resizable]
        window.level = .floating
        window.delegate = windowDelegate
        window.title = "TestView"
        
        let graph = NSHostingView(rootView: DemoView())
        graph.frame = NSRect(origin: NSPoint(x:0, y:0), size: contentSize)
        graph.autoresizingMask = [.height, .width]
        window.contentView!.addSubview(graph)
        window.center()
        window.makeKeyAndOrderFront(window)
    }
    class WindowDelegate: NSObject, NSWindowDelegate {
        func windowWillClose(_ notification: Notification) {
            NSApplication.shared.terminate(0)
        }
    }
}


//
// - This is the actual view.
//
import SwiftUI

struct DemoView: View {
    @State private var value: Int = 0
    let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
    
    func getNewNumber() {
        value = .random(in: -500...500)
    }
    
    var body: some View {
        VStack {
            HStack {
                Text("Demo view").font(.headline).colorScheme(.dark)
            }.padding(10)
            List {
                Text("hello - \(value)")
            }
        }.onReceive(timer) { _ in self.getNewNumber() }
    }
}


//
// - More AppKit boilerplate.
//
let app = NSApplication.shared
let del = AppDelegate()
app.delegate = del
app.run()