颤动：奇怪的颜色和字体大小

Question

早上好， 我最近开始使用颤振。这是我的应用：

import 'package:flutter/material.dart';

void main(){
  runApp(
    new MyButton()
  );
}

class MyButton extends StatefulWidget {
  @override
  _MyButtonState createState() => _MyButtonState();
}

class _MyButtonState extends State<MyButton> {

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Padding(
          padding: EdgeInsets.only(top: 50.0, left: 20.0, right: 20.0),
          child: Column(
            children: [
              Text("Nr. 1", textDirection: TextDirection.ltr),
              Text("Nr. 2", textDirection: TextDirection.ltr),
              Text("Nr. 3", textDirection: TextDirection.ltr),
              Row(
                textDirection: TextDirection.ltr,
                children: [
                  Text("Kind 1", textDirection: TextDirection.ltr),
                  Text("Kind 2", textDirection: TextDirection.ltr),
                  Text("Kind 3", textDirection: TextDirection.ltr),
                ],
              )
            ],
          ),
        )
    );
  }
}

但是，当我在 AVD 中运行应用程序时，它看起来像这样：

但我没有改变颜色或字体，这是什么问题？

Answer 1

你想念Scaffold。

 @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
            appBar: AppBar(
              title: Text("Sample"),
            ),
            body: Padding(
              padding: EdgeInsets.only(top: 50.0, left: 20.0, right: 20.0),
              child: Column(
                children: [
                  Text("Nr. 1", textDirection: TextDirection.ltr),
                  Text("Nr. 2", textDirection: TextDirection.ltr),
                  Text("Nr. 3", textDirection: TextDirection.ltr),
                  Row(
                    textDirection: TextDirection.ltr,
                    children: [
                      Text("Kind 1", textDirection: TextDirection.ltr),
                      Text("Kind 2", textDirection: TextDirection.ltr),
                      Text("Kind 3", textDirection: TextDirection.ltr),
                    ],
                  )
                ],
              ),
            )));
  }