main_zh.dart

import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter_ScreenUtil',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    //设置适配尺寸 (填入设计稿中设备的屏幕尺寸) 此处假如设计稿是按iPhone6的尺寸设计的(iPhone6 750*1334)
    ScreenUtil.init(context, designSize: Size(750, 1334), allowFontScaling: false);
    return ExampleWidget(title: 'FlutterScreenUtil 示例');
  }
}

class ExampleWidget extends StatefulWidget {
  const ExampleWidget({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _ExampleWidgetState createState() => _ExampleWidgetState();
}

class _ExampleWidgetState extends State<ExampleWidget> {
  @override
  Widget build(BuildContext context) {
    printScreenInformation();
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: SingleChildScrollView(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Row(
              children: <Widget>[
                Container(
                  padding: EdgeInsets.all(ScreenUtil().setWidth(10)),
                  width: ScreenUtil().setWidth(375),
                  height: ScreenUtil().setHeight(200),
                  color: Colors.red,
                  child: Text(
                    '我的宽度:${0.5.wp}dp \n'
                    '我的高度:${ScreenUtil().setHeight(200)}dp',
                    style: TextStyle(color: Colors.white, fontSize: ScreenUtil().setSp(24)),
                  ),
                ),
                Container(
                  padding: EdgeInsets.all(ScreenUtil().setWidth(10)),
                  width: 375.w,
                  height: 200.h,
                  color: Colors.blue,
                  child: Text(
                      '我的宽度:${375.w}dp \n'
                      '我的高度:${200.h}dp',
                      style: TextStyle(color: Colors.white, fontSize: ScreenUtil().setSp(24))),
                ),
              ],
            ),
            Text('设备宽度:${ScreenUtil().screenWidthPx}px'),
            Text('设备高度:${ScreenUtil().screenHeightPx}px'),
            Text('设备宽度:${ScreenUtil().screenWidth}dp'),
            Text('设备高度:${ScreenUtil().screenHeight}dp'),
            Text('设备的像素密度:${ScreenUtil().pixelRatio}'),
            Text('底部安全区距离:${ScreenUtil().bottomBarHeight}dp'),
            Text('状态栏高度:${ScreenUtil().statusBarHeight}dp'),
            Text(
              '实际宽度的dp与设计稿px的比例:${ScreenUtil().scaleWidth}',
              textAlign: TextAlign.center,
            ),
            Text(
              '实际高度的dp与设计稿px的比例:${ScreenUtil().scaleHeight}',
              textAlign: TextAlign.center,
            ),
            SizedBox(
              height: 100.h,
            ),
            Text('系统的字体缩放比例:${ScreenUtil().textScaleFactor}'),
            Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
                Text(
                  '我的文字大小在设计稿上是24px，不会随着系统的文字缩放比例变化',
                  style: TextStyle(
                    color: Colors.black,
                    fontSize: 24.sp,
                  ),
                ),
                Text(
                  '我的文字大小在设计稿上是24px，会随着系统的文字缩放比例变化',
                  style: TextStyle(
                    color: Colors.black,
                    fontSize: 24.ssp,
                  ),
                ),
              ],
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.title),
        onPressed: () {
          ScreenUtil.init(
            context,
            designSize: Size(750, 1334),
            allowFontScaling: false,
          );
          setState(() {});
        },
      ),
    );
  }

  void printScreenInformation() {
    print('设备宽度:${ScreenUtil().screenWidth}'); //Device width
    print('设备高度:${ScreenUtil().screenHeight}'); //Device height
    print('设备的像素密度:${ScreenUtil().pixelRatio}'); //Device pixel density
    print(
      '底部安全区距离:${ScreenUtil().bottomBarHeight}dp',
    ); //Bottom safe zone distance，suitable for buttons with full screen
    print(
      '状态栏高度:${ScreenUtil().statusBarHeight}dp',
    ); //Status bar height , Notch will be higher Unit px

    print('实际宽度的dp与设计稿px的比例:${ScreenUtil().scaleWidth}');
    print('实际高度的dp与设计稿px的比例:${ScreenUtil().scaleHeight}');

    print(
      '宽度和字体相对于设计稿放大的比例:${ScreenUtil().scaleWidth * ScreenUtil().pixelRatio}',
    );
    print(
      '高度相对于设计稿放大的比例:${ScreenUtil().scaleHeight * ScreenUtil().pixelRatio}',
    );
    print('系统的字体缩放比例:${ScreenUtil().textScaleFactor}');

    print('屏幕宽度的0.5:${0.5.wp}');
    print('屏幕高度的0.5:${0.5.hp}');
  }
}