SwiftUI iOS - how to capture hardware key events

Question

I’m new to iOS development. Following a tutorial I have created a simple calculator using SwiftUI.

I have a keyboard attached to my iPad, and I would like to be able

Answer 1

It needs to override hosting view controller instead and all works. Tested with Xcode 11.2 / iOS 13.2

Here is example code

class KeyTestController<Content>: UIHostingController<Content> where Content: View {

    override func becomeFirstResponder() -> Bool {
        true
    }

    override var keyCommands: [UIKeyCommand]? {
        return [
            UIKeyCommand(input: "1", modifierFlags: [], action: #selector(test)),
            UIKeyCommand(input: "0", modifierFlags: [], action: #selector(test)),
            UIKeyCommand(input: UIKeyCommand.inputLeftArrow, modifierFlags: [], action: #selector(test))
        ]
    }

    @objc func test(_ sender: UIKeyCommand) {
        print(">>> test was pressed")
    }

}

and somewhere in SceneDelegate below

window.rootViewController = KeyTestController(rootView: contentView)