test3.dart

import 'package:another_flushbar/flushbar.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      showSemanticsDebugger: false,
      home: LoginScreen(),
    ),
  );
}

class LoginScreen extends StatefulWidget {
  @override
  State<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {
  Flushbar? flushbar;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Column(
        children: [ElevatedButton(onPressed: () {
          msg();
        }, child: Text('Alert')),
        ],
      ),
    );
  }

  void msg() {
    Flushbar(
      title: 'Error',
      message: 'Invalid username or password',
      duration: Duration(seconds: 4),
      icon: Icon(
        Icons.highlight_remove_outlined,
        size: 28,
        color: Colors.white,
      ),
      backgroundColor: Colors.red,
      flushbarPosition: FlushbarPosition.TOP,
      margin: EdgeInsets.symmetric(horizontal: 10),
      borderRadius: BorderRadius.circular(8),
    );
    flushbar?.show(context);
  }

  /**
   * msg method version to stop duplicate flush showing
   * (cancels the old one and start a new one)*/
  // void msg() {
  //   flushbar?.dismiss();
  //    flushbar = Flushbar(
  //     title: 'Error',
  //     message: 'Invalid username or password',
  //     duration: Duration(seconds: 4),
  //     icon: Icon(
  //       Icons.highlight_remove_outlined,
  //       size: 28,
  //       color: Colors.white,
  //     ),
  //     backgroundColor: Colors.red,
  //     flushbarPosition: FlushbarPosition.TOP,
  //     margin: EdgeInsets.symmetric(horizontal: 10),
  //     borderRadius: BorderRadius.circular(8),
  //    );
  //    flushbar?.show(context);
  // }
}