title: How to add following decoration to TextFormField in flutter?
body: <p>Following is my code where I am trying to add form TextFormField with decoration as seen in mock:</p>
  
  <ul>
  <li>Rounded border</li>
  <li>Background colour to grey</li>
  <li>First email and then password with text not visible</li>
  <li>Where password field will have show button to make password visible</li>
  <li>finally a rounded submit button</li>
  </ul>
  
  <p>MOCK:</p>
  
  <p><a href="https://i.stack.imgur.com/kGZVb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kGZVb.png" alt="mock"></a></p>
  
  <p>CODE:</p>
  
  <pre><code>class MyCustomFormState extends State&lt;MyCustomForm&gt; {
    final _formKey = GlobalKey&lt;FormState&gt;();
  
    @override
    Widget build(BuildContext context) {
      // Build a Form widget using the _formKey created above.
      return Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: &lt;Widget&gt;[
            TextFormField(
              decoration: InputDecoration(
                fillColor: Colors.grey,
                focusColor: Colors.grey
              ),
              validator: (value) {
                if (value.isEmpty) {
                  return 'Your email';
                }
                return null;
              },
            ),
            TextFormField(
              decoration: InputDecoration(
                fillColor: Colors.grey,
                focusColor: Colors.grey
              ),
              validator: (value) {
                if (value.isEmpty) {
                  return 'Your password';
                }
                return null;
              },
            ),
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 16.0),
              child: RaisedButton(
                onPressed: () {
                  // Validate returns true if the form is valid, or false
                  // otherwise.
                  if (_formKey.currentState.validate()) {
                    // If the form is valid, display a Snackbar.
                    Scaffold.of(context)
                        .showSnackBar(SnackBar(content: Text('Processing Data')));
                  }
                },
                child: Text('Submit'),
              ),
            ),
          ],
        ),
      );
    }
  }
  </code></pre>
  
  <p>EDIT:</p>
  
  <p>How to change color of this label ?</p>
  
  <p><a href="https://i.stack.imgur.com/cEI6P.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cEI6P.png" alt="result"></a></p>