title: Flutter - 'initialValue == null || controller == null': is not true. error
body: <p>I'm trying to set an initial value for the text field. But I Can't set the initial value in text form field. I'm getting this error <code>'initialValue  == null || controller == null': is not true</code> .</p>
  
  <p>code:</p>
  
  <pre><code> Widget buildFirstName(BuildContext context) {
   valueBuilder = valueBuild();
  
  return TextFormField(
    controller: firstNameController,
    initialValue: valueBuilder,
    decoration: InputDecoration(
      hintText: "Enter Name",
      fillColor: Colors.white,
      hintStyle: TextStyle(
          color: Color.fromRGBO(0, 0, 0, 1.0),
          fontFamily: "SFProText-Regular"),
    ),
    validator: validatingName,
  );
  </code></pre>
  
  <p>}</p>