The method '*' was called on null.

[pratikbutani]

Implemented sizer: ^1.1.8 but getting error when I set it as following:

SizedBox(height: 20.0.h),

Error:

======== Exception caught by widgets library =======================================================
The following NoSuchMethodError was thrown building LoginWithSet(dirty, dependencies: [_FocusMarker, MediaQuery, _InheritedTheme, _LocalizationsScope-[GlobalKey#39772]], state: _LoginWithSetState#2e207):
The method '*' was called on null.
Receiver: null
Tried calling: *(20.0)

The relevant error-causing widget was: 
  
When the exception was thrown, this was the stack: 
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1      SizerUtil.height (package:sizer/sizer_util.dart:32:20)
#2      SizerExt.h (package:sizer/sizer_ext.dart:7:29)
#3      StatefulElement.build (package:flutter/src/widgets/framework.dart:4744:28)
...

[fayisode]

Same issue here.

[pratikbutani]

Solved. May you forgot this lines to add in main.dart

return LayoutBuilder(
      builder: (context, constraints) {
        return OrientationBuilder(
          builder: (context, orientation) {
            SizerUtil().init(constraints, orientation);
            return MaterialApp(
              debugShowCheckedModeBanner: false,
              title: 'Sizer',
              theme: ThemeData.light(),
              home: HomeScreen(),
            );
          },
        );
      },
    );

[fayisode]

It's working fine now.

[harshilishere]

I have these lines in my main.dart but still getting this error. What is the basic reason for this error!?!!?
Please someone help.

`import 'package:flutter/material.dart';
import 'home_page.dart';

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

class MyApp extends StatelessWidget {
// This widget is the root of your application.
@OverRide
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,),
home: HomePage(),
);
}
}
`