title: SwiftUI: How to make TextField become first responder?
body: <p>Here's my <code>SwiftUI</code> code:</p>
  
  <pre><code>struct ContentView : View {
  
      @State var showingTextField = false
      @State var text = ""
  
      var body: some View {
          return VStack {
              if showingTextField {
                  TextField($text)
              }
              Button(action: { self.showingTextField.toggle() }) {
                  Text ("Show")
              }
          }
      }
  }
  </code></pre>
  
  <p>What I want is when the text field becomes <em>visible</em>, to make the text field become the first responder (i.e. receive focus &amp; have the keyboard pop up).</p>