推送视图控制器时标签不显示

Question

My label is not showing up when I push the view controller, does anyone know why and how to fix it?

@IBAction func tapButton (_ sender: Any) {

    let vc = UIViewController()
    Vc.view.backgroundColor = .gray
    
    let label = UILabel()
    
    label.font = UIFont(name: “Arial”, size: 16.0)
    
    label.text = “Test label”
    
    Other label configurations...
    
    vc.view.addSubView(label)
    
    navigationController?.pushViewController(vc, animated: true)

}

Answer 1

You should add some constraints to your label (in order to position it on the second View Controller):

    @IBAction func buttonDidTap(_ sender: UIButton) {
        
        let vc = UIViewController()
        vc.view.backgroundColor = .lightGray
        
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = "TestTest"
        
        vc.view.addSubview(label)
        
        NSLayoutConstraint.activate([
            label.centerYAnchor.constraint(equalTo: vc.view.centerYAnchor),
            label.centerXAnchor.constraint(equalTo: vc.view.centerXAnchor)
        ])
        
        navigationController?.pushViewController(vc, animated: true)
    }