How do I fix dart flutter scaffoldKey problem? - flutter

Question

I will describe my coding problem.
Well I have created Login/signUp .dart files(pages) but while debugging I got this error...
The method 'showSnackBar' isn`t defined for the type 'ScaffoldState'.
This error message appears everywhere in .dart code where I have this coding line...
`
scaffoldKey.currentState.showSnackBar(snackbar);
`
Here below is full code of my "login_page.dart" file...
`
class LoginPage extends StatefulWidget {
#override
_LoginPageState createState() => _LoginPageState();
}
class _LoginPageState extends State<LoginPage> {
final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>();
void showSnackBar(String title) {
final snackbar = SnackBar(
content: Text(
title,
textAlign: TextAlign.center,
style: TextStyle(fontSize: 15),
),
);
scaffoldKey.currentState.showSnackBar(snackbar);
}
var emailIdController = TextEditingController();
var passwordController = TextEditingController();
Widget _buildLogin() {
return Padding(
padding: EdgeInsets.symmetric(horizontal: 30),
child: Column(
children: [
InputTextField(
controller: emailIdController,
label: 'Email-Id',
icon: Icon(Icons.email_outlined),
),
InputTextField(
controller: passwordController,
label: 'Password',
icon: Icon(Icons.lock),
),
SizedBox(
height: 50,
),
GestureDetector(
onTap: () async {
// network connectivity
var connectivityResult = await Connectivity().checkConnectivity();
if (connectivityResult != ConnectivityResult.mobile &&
connectivityResult != ConnectivityResult.wifi) {
showSnackBar('No Internet connectivity');
return;
}
if (!emailIdController.text.contains('#')) {
showSnackBar('Please provide a valid email address');
}
if (passwordController.text.length < 6) {
showSnackBar('Please provide a password of length more than 6');
}
BuildContext dialogContext;
showDialog(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
dialogContext = context;
return ProgressDialog(
status: 'Logging you in...',
);
},
);
context
.read<AuthenticationService>()
.signIn(
email: emailIdController.text.trim(),
password: passwordController.text.trim(),
)
.then((value) => Navigator.push(
context,
MaterialPageRoute(builder: (context) {
return HomePage();
}),
));
Navigator.pop(dialogContext);
},
child: CustomButton(
text: 'Login',
),
),
Text("\nDon't have any account?"),
GestureDetector(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) {
return SignUpPage();
}),
);
},
child: Text(
'SignUp here',
style: TextStyle(fontWeight: FontWeight.bold, fontSize: 12),
),
),
SizedBox(
height: 20,
),
],
),
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
key: scaffoldKey,
body: SingleChildScrollView(
physics: BouncingScrollPhysics(),
child: Padding(
padding: EdgeInsets.only(top: 130),
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Text(
'hopOn',
style: TextStyle(
fontSize: 60,
letterSpacing: 2,
fontWeight: FontWeight.bold,
fontFamily: 'MuseoModerno',
// color: Colors.white,
),
),
SizedBox(height: 80),
Padding(
padding: EdgeInsets.symmetric(horizontal: 30),
child: Column(
children: [
InputTextField(
controller: emailIdController,
label: 'Email-Id',
obscure: false,
icon: Icon(Icons.email_outlined),
),
InputTextField(
controller: passwordController,
label: 'Password',
obscure: true,
icon: Icon(Icons.lock),
),
SizedBox(
height: 30,
),
GestureDetector(
onTap: () async {
// network connectivity
var connectivityResult =
await Connectivity().checkConnectivity();
if (connectivityResult != ConnectivityResult.mobile &&
connectivityResult != ConnectivityResult.wifi) {
showSnackBar('No Internet connectivity');
return;
}
if (!emailIdController.text.contains('#')) {
showSnackBar(
'Please provide a valid email address');
}
if (passwordController.text.length < 6) {
showSnackBar(
'Please provide a password of length more than 6');
}
BuildContext dialogContext;
showDialog(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
dialogContext = context;
return ProgressDialog(
status: 'Logging you in...',
);
},
);
context
.read<AuthenticationService>()
.signIn(
email: emailIdController.text.trim(),
password: passwordController.text.trim(),
)
.then((value) => Navigator.push(
context,
MaterialPageRoute(builder: (context) {
return HomePage();
}),
));
Navigator.pop(dialogContext);
},
child: CustomButton(
text: 'Login',
),
),
SizedBox(
height: 20,
),
GestureDetector(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) {
return SignUpPage();
}),
);
},
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
"Don't have any account?\t",
style: TextStyle(fontSize: 10),
),
Text(
'SignUp here',
style: TextStyle(
fontWeight: FontWeight.bold, fontSize: 12),
),
],
),
),
SizedBox(
height: 20,
),
],
),
),
],
),
),
),
),
);
}
}
`
The problem from whole code appears in this class...
`
void showSnackBar(String title) {
final snackbar = SnackBar(
content: Text(
title,
textAlign: TextAlign.center,
style: TextStyle(fontSize: 15),
),
);
scaffoldKey.currentState.showSnackBar(snackbar); // <=== here is problem, this line have error message --> The method 'showSnackBar' isn`t defined for the type 'ScaffoldState'.
}
`
Any help is appreciated.
Thank you!
I would like to fix that "snackBar" error problem.
I tryed several hours to fix it by myself but without succees.

Answer 1

Flutter uses below method to display the snackbar as per flutter.dev
ScaffoldMessenger.of(context).showSnackBar(snackBar);

Answer 2

I found a solution idea that other user named "Rohan" gave to me.
I changed problematic code line...
scaffoldKey.currentState.showSnackBar(snackbar);
to first solution (which still didn't worked,, appeared error "Undefined name: 'snackbar'")...
ScaffoldMessenger.of(context).showSnackBar(snackBar);
Didn`t worked, but then I found a solution from previous sample solution. This is general and working Solution for my problem...
ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: snackbar));
This solution will help you, if you found the same or similar issue with "showSnackBar".