flutter 宽度屏幕适配

计算公式：

实际尺寸 = UI 尺寸 * 设备宽度 / 设计图宽度

import 'package:flutter/material.dart';

class Adapt {
  static MediaQueryData mediaQuery = MediaQueryData.fromWindow(window);  //获得设备屏幕
  static double _width = mediaQuery.size.width;
  static double _height = mediaQuery.size.height;
  static double _topbarH = mediaQuery.padding.top;
  static double _botbarH = mediaQuery.padding.bottom;
  static double _pixelRatio = mediaQuery.devicePixelRatio;
  static var _ratio;
  static init(int number){  //初始化圆形图尺寸
    int uiwidth = number is int ? number : 750;
    _ratio = _width / uiwidth;
  }
  static px(number){
    if(!(_ratio is double || _ratio is int)){Adapt.init(750);}
    return number * _ratio;
  }
  static onepx(){
    return 1/_pixelRatio;
  }
  static screenW(){
    return _width;
  }
  static screenH(){
    return _height;
  }
  static padTopH(){
    return _topbarH;
  }
  static padBotH(){
    return _botbarH;
  }
}