trackoffical_app/lib/screen.dart

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:trackoffical_app/styles/color_schemes.g.dart';


class SizeFit{
  static double _screenWidth = 0;
  static double _screenHeight = 0;

  static double _screenWidthD = 0;
  static double _screenHeightD = 0;

  static double _rpx=0;
  static double _px=0;

  static const double standardWidth = 750;
  static void screenInit(BuildContext context){
    _screenWidthD = context.width;
    _screenHeightD = context.height;
    final physicalSize = View.of(context).physicalSize;
    // 获取物理分辨率
    var physicalWidth=physicalSize.width;
    var physicalHeight=physicalSize.height;
    //获取dpr
    var dpr=context.devicePixelRatio;

    _screenWidth = physicalWidth/dpr;
    _screenHeight = physicalHeight/dpr;

    // 计算rpx 和px大小
    _rpx = _screenWidth / standardWidth;
    _px = _screenWidth / standardWidth * 2;  // 必须是乘以2，因为是以iphone6(750)为标准
  }

  // 按照像素来设置
  static double setPx(double size) {
    return _px * size ;
  }

  // 按照rpx来设置(如果给的设计稿是物理像素用rpx)
  static double setRpx(double size) {
    return _rpx * size;
  }
}



extension MNumFit on num {


  double get px {
    //这里的this是数字200.0, 相当于使用时 width: 200.0.px 里面的200.0 ，相当于是它调用方法
    return SizeFit.setPx(toDouble());
  }

  double get rpx {
    //这里和上面都是用的get ,所以外面使用的时候是:width:200.5.rpx
    return SizeFit.setRpx(toDouble());
  }

  /// 屏幕宽度百分比
  double get wp{
    return SizeFit._screenWidthD * (toDouble()/100);
  }

  /// 屏幕高度百分比
  double get hp{
    return SizeFit._screenHeightD * (toDouble()/100);
  }

}


class Preview extends StatelessWidget{
  const Preview({super.key, required this.child});

  final Widget child;

  @override
  Widget build(BuildContext context) {
    SizeFit.screenInit(context);
    return child;
  }
}


void runPreview(Widget child){
  runApp(GetMaterialApp(
      theme: ThemeData(useMaterial3: true, colorScheme: lightColorScheme),
      home: Preview(child: child)));
}