SnackBar

import 'package:flutter/material.dart';

class ShowSnackBar extends StatefulWidget {
  const ShowSnackBar({Key? key}) : super(key: key);

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

class _ShowSnackBarState extends State<ShowSnackBar> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: const Text("Elevated Buttons")),
        body: Container(
            padding: const EdgeInsets.all(20),
            alignment: Alignment.center,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: [
                buttonForSimpleSnackBar(context),
                const SizedBox(height: 50),
                buttonForSnackBarWithAction(context),
              ],
            )
        )
    );
  }

  /// **********************************************************************
  /// Button for simple snackbar example
  /// **********************************************************************
  Widget buttonForSimpleSnackBar(BuildContext context) {
    return ElevatedButton(
        onPressed: () {
          displaySnackBar(context);
        },
        style: ElevatedButton.styleFrom(
            backgroundColor: Colors.blue,
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20.0))
        ),
        child: const Text("Press to display a snackbar")
    );
  }

  /// **********************************************************************
  /// Simple snackbar
  /// **********************************************************************
  void displaySnackBar(BuildContext context) {

      var snackBar = const SnackBar(content: Text("Simple snackbar"));

      ScaffoldMessenger.of(context).showSnackBar(snackBar);
  }

  /// **********************************************************************
  /// Button for snackbar with action example
  /// **********************************************************************
  Widget buttonForSnackBarWithAction(BuildContext context) {
    return ElevatedButton(
        onPressed: () {
          displaySnackBarAction(context);
        },
        style: ElevatedButton.styleFrom(
            backgroundColor: Colors.red,
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20.0))
        ),
        child: const Text("Press to display a snackbar with action")
    );
  }

  /// **********************************************************************
  /// Snackbar with action example
  /// **********************************************************************
  void displaySnackBarAction(BuildContext context) {

    var snackBar = SnackBar(
        content: const Text("Action launched..."),
        action: SnackBarAction(
            label: "Cancel",
            onPressed: () {
              print("Action canceled"); },
            ),
    );

    ScaffoldMessenger.of(context).showSnackBar(snackBar);

  }
}