【发布时间】：2021-04-02 22:29:23
【问题描述】：
我正在尝试在 Flutter Web 中使用 MediaQuery，如下所示：
class Login extends StatefulWidget {
@override
_LoginState createState() => _LoginState();
}
class _LoginState extends State<Login> {
Size size;
MediaQueryData mediaQuerydata;
@override
Widget build(BuildContext context) {
mediaQuerydata = MediaQuery.of(context);
size = MediaQuery.of(context).size;
return Container();
}
════════小部件库捕获的异常═════════════════════════════════════ ═ 在构建 LoginWithMobile$(dirty, dependencies: [MediaQuery], state: _LoginWithMobileState#2a7a8) 时引发了以下 UnsupportedError： 不支持的操作：Platform._operatingSystem
相关的导致错误的小部件是 LoginWithMobile$ lib/main.dart:84 抛出异常时，这是堆栈 dart-sdk/lib/internal/js_dev_runtime/private/ddc_runtime/errors.dart 216:49 throw dart-sdk/lib/_internal/js_dev_runtime/patch/io_patch.dart 244:5 _operatingSystem dart-sdk/lib/io/platform_impl.dart 58:40 获取操作系统 dart-sdk/lib/io/platform.dart 65:45 获取 _operatingSystem dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 802:8 获取
颤振医生输出：
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, 1.25.0-8.1.pre, on macOS 11.1 20C69
darwin-x64, locale en-IN)
[✓] Android toolchain - develop for Android devices (Android SDK
version 30.0.2)
[✓] Xcode - develop for iOS and macOS (Xcode 12.2)
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.0)
[✓] VS Code (version 1.52.1)
[✓] Connected device (2 available)
! Error: iPhone is not connected. Xcode will continue when
iPhone is connected. (code -13)
• No issues found!
【问题讨论】：
标签： flutter dart flutter-web