replace 0.00 of user input and move one step backward in flutter

Question

sample layout input of textfield with initial value 0.00

In flutter when user input digit number, i want it to be like always replacing last digit of number and move one step backward

Example: default value is 0.00 with fixed 2 decimals place

User Input	Output
3	0.03
5	0.35
1	3.51
0	35.10

This article [Handle changes to a text field](https://docs.flutter.dev/cookbook/forms/text-field-changes) should answer your question. — Ουιλιαμ Αρκευα, Oct 12 '22 at 17:11
i need some help on regex or padleft/padright when user input a new digit and the text will shift to left one position — gan jinqu, Oct 17 '22 at 05:35

score 0 · Answer 1 · answered Oct 12 '22 at 19:32

I am doing hard-coded, Play with this widget.

class MyStatelessWidget extends StatefulWidget {
  const MyStatelessWidget({super.key});

  @override
  State<MyStatelessWidget> createState() => _MyStatelessWidgetState();
}

class _MyStatelessWidgetState extends State<MyStatelessWidget> {
  String text = "0.00";
  late final TextEditingController controller;

  @override
  void initState() {
    super.initState();

    controller = TextEditingController()
      ..addListener(() {
        final data = controller.text;
        log(data);
        switch (data.length) {
          case 0:
            setState(() {
              text = "0.00";
            });
            return;
          case 1:
            setState(() {
              text = "0.0$data";
            });

            break;
          case 2:
            setState(() {
              text = "0.$data";
            });
            break;
          case 3:
            setState(() {
              text = data[0] + "." + data.substring(1);
            });
            break;
          default:
            setState(() {
              text = data.substring(0, data.length - 2) +
                  "." +
                  data.substring(data.length - 2);
            });
        }
      });
  }

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
          child: Column(
        children: [
          Text(text),
          TextField(
            controller: controller,
          ),
        ],
      )),
    );
  }
}

Maybe padLeft or InputFormatter is better option for TextFiled. I am assuming you are using buttons from your UI.

replace 0.00 of user input and move one step backward in flutter

1 Answers1