import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() { runApp(MyWidget()); }

class MyWidget extends StatefulWidget {

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

class _MyWidgetState extends State<MyWidget> {

final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();

final snackBar = SnackBar(content: Text("Hello, world"));

final snackBar1 = SnackBar(content: Text("Thank you for joining our app"));

@override

Widget build(BuildContext context) {

return MaterialApp(

   theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue), 

  debugShowCheckedModeBanner: false,

  home:Scaffold( 

    appBar:AppBar(

    title:Text("App"),

    ),
     key: _scaffoldKey,

  body:Column(

    crossAxisAlignment: CrossAxisAlignment.stretch,

  children:<Widget>[

    Padding(
    padding:const EdgeInsets.all(10.0),
      child:MaterialButton(
      child:Text("SnackBar"),
        color:Colors.lightBlue,
        textColor:Colors.white,
        splashColor:Colors.green,
        onPressed:(){

           _scaffoldKey.currentState.removeCurrentSnackBar();
_scaffoldKey.currentState.showSnackBar(snackBar1);
          //showSnakbar();
        },
      ),

    ),

     Padding(

    padding:const EdgeInsets.all(10.0),
      child:MaterialButton(
      child:Text("touch Me"),
        color:Colors.green,
        textColor:Colors.white,
        splashColor:Colors.green,
        onPressed:(){

            _scaffoldKey.currentState.removeCurrentSnackBar();
_scaffoldKey.currentState.showSnackBar(snackBar);
        },
      ),


    ),


  ]
  ),
)

  );

}

}