flutter - MediaQuery.of()一直显示

Question

我在观看视频教程的同时尝试向我的flutter项目添加2个按钮

void main() {
  runApp(MainScreen());
}

class MainScreen extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Main Screen'),
        centerTitle: true,
        backgroundColor: Colors.white,
      ),
    );
  }

}

这是我编码的唯一行，并且出现此错误

MediaQuery.of() called with a context that does not contain a MediaQuery.

Answer 1

您需要使用MaterialApp包装所有小部件。试试这个:

  
class MainScreen extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Main Screen'),
          centerTitle: true,
          backgroundColor: Colors.white,
        ),
      ),
    );
  }

}

您可以从 this blog阅读更多内容。