flutter custom text switch controller

custom_switch.dart

import 'package:flutter/material.dart';

class CustomSwitch extends StatefulWidget {
  const CustomSwitch(
      {Key? key, required this.leftStr, required this.rightStr, this.onChange})
      : super(key: key);

  final String leftStr;
  final String rightStr;
  final Function(int selected)? onChange;

  @override
  State<StatefulWidget> createState() {
    return _CustomSwitch();
  }
}

class _CustomSwitch extends State<CustomSwitch> {
  final TextStyle _textStyle =
      const TextStyle(fontSize: 10, color: Colors.white);
  var selected = 0;

  void onItemSelected(int idx) {
    setState(() {
      selected = idx;
    });

    if (widget.onChange != null) {
      widget.onChange?.call(idx);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: const BoxDecoration(
          color: Color(0xff5E3BF5),
          borderRadius: BorderRadius.all(Radius.circular(60))),
      child: SizedBox(
          width: 60,
          height: 18,
          child: Row(
            children: [
              _buildItem(
                  widget.leftStr, selected == 0, () => onItemSelected(0)),
              _buildItem(
                  widget.rightStr, selected == 1, () => onItemSelected(1)),
            ],
          )),
    );
  }

  _buildItem(String text, bool isSelected, GestureTapCallback cb) {
    return Expanded(
        flex: 1,
        child: InkWell(
          onTap: cb,
          child: Container(
            height: 27,
            alignment: Alignment.center,
            decoration: BoxDecoration(
                borderRadius: const BorderRadius.all(Radius.circular(20)),
                color: isSelected
                    ? const Color(0xff9279FE)
                    : const Color(0x000000ff)),
            child: Text(
              text,
              style: _textStyle,
            ),
          ),
        ));
  }
}