title: UIView not showing in UIViewcollection in Swift, Programmatically
body: <p>the below code is the viewController that is navigated with a navigationItem <code>navigationItem.leftBarButtonItem = UIBarButtonItem(title:</code> from a previous tableViewController and I am trying to produce a UIView in my viewController. However nothing is showing. </p>
  
  <pre><code>import UIKit
  
  
  class SecondpgController: UIViewController {
       var inputContainerView: UIView!
       override func viewDidLoad() {
         super.viewDidLoad()
  
      view.backgroundColor = UIColor .gray
  
        let inputContainerView = UIView()
      self.view.addSubview(inputContainerView)
      //inputContainerView.backgroundColor = UIColor(red: 162/255, green: 20/255, blue: 35/255, alpha: 1)
  
      inputContainerView.backgroundColor = .white
      inputContainerView.translatesAutoresizingMaskIntoConstraints = false
  
      //inputContainerView.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 300).isActive = true
      //nputContainerView.leftAnchor.constraint(equalTo: self.view.leftAnchor, constant: 10).isActive = true
      inputContainerView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor, constant: 200).isActive = true
      inputContainerView.centerYAnchor.constraint(equalTo: self.view.centerYAnchor, constant: 200).isActive = true
  </code></pre>
  
  <p>The app is running well however after reaching the view controller, Nothing is shown but only a grey screen.
  Why is this happening and how can I solve it?</p>