Size configuration of flutter

Sizes.dart

import 'package:flutter/widgets.dart';

class Sizes {
  static MediaQueryData _mediaQueryData;
  static double screenWidth;
  static double screenHeight;
  static double blockSizeHorizontal;
  static double blockSizeVertical;
  static double _safeAreaHorizontal;
  static double _safeAreaVertical;
  static double safeBlockHorizontal;
  static double safeBlockVertical;

  //for font sizing
  static double verySmall;
  static double small;
  static double medium;
  static double large;
  static double xlarge;
  static double xxlarge;
  static double heading;

  void init(BuildContext context) {
    _mediaQueryData = MediaQuery.of(context);
    screenWidth = _mediaQueryData.size.width;
    screenHeight = _mediaQueryData.size.height;
    blockSizeHorizontal = screenWidth / 100;
    blockSizeVertical = screenHeight / 100;
    _safeAreaHorizontal =
        _mediaQueryData.padding.left + _mediaQueryData.padding.right;
    _safeAreaVertical =
        _mediaQueryData.padding.top + _mediaQueryData.padding.bottom;
    safeBlockHorizontal = (screenWidth - _safeAreaHorizontal) / 100;
    safeBlockVertical = (screenHeight - _safeAreaVertical) / 100;

    verySmall = blockSizeHorizontal * 3;
    small = blockSizeHorizontal * 3.5;
    medium = blockSizeHorizontal * 4;
    heading = blockSizeHorizontal * 4.5;
    large = blockSizeHorizontal * 5;
    xlarge = blockSizeHorizontal * 6;
    xxlarge = blockSizeHorizontal * 7;
  }
}

void hideKeyboard(BuildContext context) {
  FocusScope.of(context).unfocus();
}

Size screenSize(BuildContext context) {
  return MediaQuery.of(context).size;
}

double screenHeight(BuildContext context,
    {double dividedBy = 1, double reducedBy = 0.0}) {
  return (screenSize(context).height - reducedBy) / dividedBy;
}

double screenWidth(BuildContext context,
    {double dividedBy = 1, double reducedBy = 0.0}) {
  return (screenSize(context).width - reducedBy) / dividedBy;
}