Flutter 混编场景下 flutter_screenutil 踩坑与架构防坑实战指南

// ❌ 混编致命陷阱
void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await ScreenUtil.ensureScreenSize();
  runApp(const MyApp());
}

static Future<void> ensureScreenSize([
  ui.FlutterView? window,
  Duration duration = const Duration(milliseconds: 10),
]) async {
  final binding = WidgetsFlutterBinding.ensureInitialized();
  binding.deferFirstFrame(); // 🔴 致命点 1：通知引擎挂起首帧，不允许渲染任何内容

  await Future.doWhile(() {
    if (window == null) {
      window = binding.platformDispatcher.implicitView;
    }
    // 🔴 致命点 2：若 View 为空或尺寸为空，每隔 10ms 循环一次
    if (window == null || window!.physicalSize.isEmpty) {
      return Future.delayed(duration, () => true);
    }
    return false;
  });

  binding.allowFirstFrame(); // 🔴 永远走不到这里
}

void _revalidate([void Function()? callback]) {
  final oldData = _mediaQueryData;
  final newData = _newData();
  if (newData == null) return;

  // 🔴 致命点：默认的 rebuildFactor 仅仅比较 oldData.size != newData.size
  if (oldData == null || widget.rebuildFactor(oldData, newData)) {
    setState(() {
      _mediaQueryData = newData; // 接收了 newData
      _updateTree(context as Element);
      callback?.call();
    });
  }
}

ScreenUtil.enableScale(
  enableWH: () => ScreenUtil().screenWidth > 0,
  enableText: () => ScreenUtil().screenWidth > 0,
);

@override
void initState() {
  ...
  // 🔴 致命点：ScreenUtilInit 初始化时直接将 widget.enableScaleWH 写入单例
  ScreenUtil.enableScale(enableWH: widget.enableScaleWH, enableText: widget.enableScaleText);
  ...
}

class _MyPageState extends State<MyPage> {
  // ❌ 致命隐患：State 的实例属性字段求值
  final _tabs = [
    Text('我接的订单', style: TextStyle(fontSize: 14.sp)),
    Text('我发的订单', style: TextStyle(fontSize: 14.sp)),
  ];

  @override
  Widget build(BuildContext context) {
    return TabBar(tabs: _tabs);
  }
}

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

// 设计稿基础尺寸（按实际业务标准设定）
const Size designSize = Size(375, 812);

/// 混编安全字体缩放解析器：防止首帧尺寸未就绪时 scaleText <= 0 导致字号计算为 0
double _safeFontSizeResolver(num fontSize, ScreenUtil instance) {
  try {
    final scale = instance.scaleText;
    if (scale <= 0 || scale.isNaN) return fontSize.toDouble();
    return fontSize * scale;
  } catch (_) {
    return fontSize.toDouble();
  }
}

void main() async {
  CustomFlutterBinding();
  WidgetsFlutterBinding.ensureInitialized();

  // 1. 全局单例直接注入安全解析器，杜绝任何时间点调用 .sp 返回 0
  ScreenUtil().fontSizeResolver = _safeFontSizeResolver;

  // 2. 混编首帧安全保底：同步预设标准设计尺寸（纯同步无 await，杜绝黑屏卡死）
  ScreenUtil.configure(
    data: const MediaQueryData(size: designSize),
    designSize: designSize,
    minTextAdapt: true,
    splitScreenMode: true,
    fontSizeResolver: _safeFontSizeResolver,
  );

  // 3. 初始防缩放熔断
  ScreenUtil.enableScale(
    enableWH: () => ScreenUtil().screenWidth > 0,
    enableText: () => ScreenUtil().screenWidth > 0,
  );

  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Widget appBuilder(Widget home) {
    return ScreenUtilInit(
      designSize: designSize,
      minTextAdapt: true,
      splitScreenMode: true,

      // 4. 核心关键点：拦截原生拉起瞬间的 0x0 脏尺寸，防止全局 ScreenUtil 被重置为 0
      rebuildFactor: (oldData, newData) {
        if (newData.size.isEmpty || newData.size.width <= 0 || newData.size.height <= 0) {
          return false; // 拒绝 0x0 脏数据污染全局单例！
        }
        return oldData.size != newData.size;
      },

      // 5. 传入专属熔断函数，防止 ScreenUtilInit 内部将 enableScale 重置为 null
      enableScaleWH: () => ScreenUtil().screenWidth > 0,
      enableScaleText: () => ScreenUtil().screenWidth > 0,

      // 6. 绑定安全字体解析器
      fontSizeResolver: _safeFontSizeResolver,

      builder: (context, child) {
        return MaterialApp(
          home: home,
          // ... 其它全局主题与路由配置
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return FlutterBoostApp(
      _customRouteFactory,
      appBuilder: appBuilder,
    );
  }
}