Google Sign In - View Controller - Add Sign In Button

GSignIn_VC_AddButton.swift

import GoogleSignIn

class ViewController: UIViewController {
    let googleSignInButton = UIButton()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.addSubview(googleSignInButton)
        googleSignInButton.setTitle("Google Sign In", for: .normal)
        googleSignInButton.addTarget(self, action: #selector(onGoogleSignInButtonTap), for: .touchUpInside)
        // ...
    }
    
    @objc private func onGoogleSignInButtonTap() {
        GIDSignIn.sharedInstance()?.signIn()
    }
}