flutter get width of screen

double height = MediaQuery.of(context).size.height;
double width = MediaQuery.of(context).size.width;

double width = MediaQuery.of(context).size.width;
double height = MediaQuery.of(context).size.height;

getHeightWidth(context){
 
    double width = MediaQuery.of(context).size.width;
 
    double height = MediaQuery.of(context).size.height;
 
    setState(() {
     heightHolder = height.roundToDouble();
     widthHolder = width.roundToDouble() ; 
    });
 
  }

import 'package:flutter_screenutil/flutter_screenutil.dart';

dependencies:
  flutter:
    sdk: flutter
  # add flutter_ScreenUtil
  flutter_screenutil: ^0.4.2