calculus-ui-scaffold-operand.dart

class Operand extends StatefulWidget {
  final String label;
  final num initValue;

  const Operand({Key key, this.label, this.initValue}) : super(key: key);

  @override
  _OperandState createState() => _OperandState();
}

class _OperandState extends State<Operand> {
  TextEditingController controller;

  @override
  void initState() {
    super.initState();
    controller = TextEditingController(text: '${widget.initValue}');
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(top: 10, bottom: 10),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: <Widget>[
          Padding(
            padding: const EdgeInsets.only(right: 8.0),
            child: Text(widget.label,
                style: Theme.of(context).textTheme.bodyText2),
          ),
          Flexible(
            child: TextField(
              controller: controller,
              keyboardType: TextInputType.number,
              textAlign: TextAlign.end,
            ),
          ),
          Padding(
            padding: const EdgeInsets.only(left: 8.0),
            child: RaisedButton(
                onPressed: () {},
                child: Text('From memory',
                    style: Theme.of(context).textTheme.button)),
          ),
        ],
      ),
    );
  }
}