Register.dart

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(title: Text("Prestige Worldwide Registration")),
    // TODO 1: Wrap the body in a Form widget
    body: Form(  // <-- Add this widget. (Don't forget to close it!)
      child: Container(
        alignment: Alignment.center,
        child: Column(
          children: <Widget>[
            _buildEmailField,
            _buildPasswordField,
            _buildPasswordConfirmationField,
            _buildAgreeToTermsField,
          ],
        ),
      ),
    ),
    floatingActionButton: FloatingActionButton(
      child: Icon(Icons.save),
      onPressed: _doRegister,
    ),
  );
}

After adding a Form widget. Does nothing except set us up for validations in the future.