How can I display Touch Bar Buttons using SwiftUI? - macos

Question

I'm trying to add Touch Bar support for a SwiftUI View. There seems to be SwiftUI API for this using the .touchBar(content: () -> View) function on Views, but documentation is non existent and I can't get my Touch Bar to display anything.
import SwiftUI
struct ContentView: View {
var body: some View {
Text("Hello, World!")
.frame(maxWidth: .infinity, maxHeight: .infinity)
.touchBar {
Button(action: {
}) {
Text("do something")
}
}
}
}
This code does compile and run, but the Touch Bar remains empty. How can I get my touch bar to display content using SwiftUI (not catalyst)?

Answer 1

Using .focusable doesn't work without "Use keyboard navigation to move focus between controls" checked in System Preferences -> Keyboard -> Shortcuts. To work around that, I did this:
/// Bit of a hack to enable touch bar support.
class FocusNSView: NSView {
override var acceptsFirstResponder: Bool {
return true
}
}
/// Gets the keyboard focus if nothing else is focused.
struct FocusView: NSViewRepresentable {
func makeNSView(context: NSViewRepresentableContext<FocusView>) -> FocusNSView {
return FocusNSView()
}
func updateNSView(_ nsView: FocusNSView, context: Context) {
// Delay making the view the first responder to avoid SwiftUI errors.
DispatchQueue.main.asyncAfter(deadline: .now() + 0.01) {
if let window = nsView.window {
// Only set the focus if nothing else is focused.
if let _ = window.firstResponder as? NSWindow {
window.makeFirstResponder(nsView)
}
}
}
}
}

Answer 2

Help from this How to use a SwiftUI touchbar with a NSWindow - Apple Developer Forums:
Use the focusable() modifier
The touch bar shows the text when you add the .focusable() modifier just before the .touchBar(content:) modifier.
struct ContentView: View {
var body: some View {
Text("Hello, World!")
.frame(maxWidth: .infinity, maxHeight: .infinity)
.focusable()
.touchBar {
Button(action: {
print("Perform some action")
}) {
Text("do something")
}
}
}
}