Swift/Xcode: How do I detect key presses? - ios

Question

I am wondering how I could detect key presses in Xcode - my goal is to be able to detect when keys are pressed, specifically the space, escape, enter and WASD keys.
What I have tried
I have tried pressesBegan, pressesEnded and its other 'variants', and I have also tried keyDown. After looking for 2 hours, the only ways I could find to detect key presses were from the two methods listed above, which don't seem to be working for me.
When using pressesBegan, I tried putting the following code in both the GameViewController.swift file and the AppDelegate.swift file, however it doesn't seem to work:
override func pressesBegan(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
guard let key = presses.first?.key else { return }
print(key.keyCode)
}
The code shows no errors, and even when I put a print file at the very start of the function to see if it is being called it does not give any output.
After this, I tried a keyDown function (in the GameViewController.swift file), however it threw the error "Cannot find type NSEvent in scope". I fixed this error by adding ", NSObject" to the top of the file in the line "class GameViewController: UIViewController {" but that threw the error "Multiple inheritance from classes 'UIViewController' and 'NSObject'". I have looked for about an hour but there are no solutions which match my issue/have not worked for me.
import UIKit
import SpriteKit
import GameplayKit
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let view = self.view as! SKView? {
// Load the SKScene from 'GameScene.sks'
if let scene = SKScene(fileNamed: "SplashScreen") {
// Set the scale mode to scale to fit the window
scene.scaleMode = .aspectFill
// Present the scene
view.presentScene(scene)
}
view.ignoresSiblingOrder = true
view.showsFPS = true
view.showsNodeCount = true
}
}
override var shouldAutorotate: Bool {
return true
}
override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
if UIDevice.current.userInterfaceIdiom == .phone {
return .allButUpsideDown
} else {
return .all
}
}
override var prefersStatusBarHidden: Bool {
return true
}
override func pressesBegan(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
guard let key = presses.first?.key else { return }
switch key.keyCode {
case .keyboardR:
print("Roll dice")
case .keyboardH:
print("Show help")
default:
super.pressesBegan(presses, with: event)
}
}
override func keyDown(with event: NSEvent) {
print("a")
}
}
If you need any additional things I'll try to get back to you as quick as possible. I'm really sorry if I've missed something extremely obvious like putting it in a different file.
Thank you!

Answer 1

the pressesEnd() method works in the same way; Try to import UIKit first:
override func pressesEnded(_ presses: Set<UIPress>, with event: UIPressesEvent?) {
guard let key = presses.first?.key else { return }
switch key.keyCode {
case .keyboardSpacebar:
print("Continue the quiz…")
default:
super.pressesEnded(presses, with: event)
}
}
More can be found at:
https://www.hackingwithswift.com/example-code/uikit/how-to-detect-keyboard-input-using-pressesbegan-and-pressesended