flutter SWITCH

switch.dart

import 'package:flutter/material.dart';

class SwitchOnchangedListener extends StatefulWidget {
  @override
  SwitchOnchangedListenerState createState() {
    return new SwitchOnchangedListenerState();
  }
}

class SwitchOnchangedListenerState extends State<SwitchOnchangedListener> {
  bool _isChecked = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Swiutch Onchange Listener Example"),
      ),
      body: Column(
        children: <Widget>[
          Expanded(
            child: Center(
              child: Text(_isChecked ? "Switch On" : "Switch Off",
                  style: TextStyle(
                    fontSize: 20.0,
                    fontWeight: FontWeight.bold,
                    color: Colors.red,
                  )),
            ),
          ),
          Expanded(
              child: Container(
            height: 350.0,
            child: Column(
              children: [
                Switch(
                  value: _isChecked,
                  onChanged: (val) {
                    setState(() {
                      _isChecked = val;
                    });
                  },
                ),
              ],
            ),
          )),
        ],
      ),
    );
  }
}