the TextFiled class

```dart
class InputContainer extends StatefulWidget{

  final _InputContainerInner input = new _InputContainerInner();
  @override
  State<StatefulWidget> createState() {
    return input;
  }

}

class _InputContainerInner extends State<InputContainer>{
  TextEditingController controller = TextEditingController();
  String num = '';

  @override
  Widget build(BuildContext context) {
    return Container(
    ...
        child: TextField(
         ...
         controller: controller,
         ...
         )
     )
}

```

i use it in another file

```dart
Widget build(BuildContext context) {
    InputContainer passWord = new InputContainer();
    return Scaffold(
        body: new Column(
        children: <Widget>[
                passWord,
                new MaterialButton(
                    onPressed: () {
                        print(passWord.input);
                        print(passWord.input.num);

                    }
                )
            ]
        )
}

```

i click the button , but got nothing of this TextFiled, print result is 

```
flutter: InputContainerInner#9818c(lifecycle state: created, no widget, not mounted)
flutter:

```

maybe it is the matter of lifecycle, but i have made it in the widget , what happen ?