SizedBox 设置具体尺寸

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    title: "SizedBox设置具体尺寸示例",
    home: LayoutDemo(),
  ));
}

class LayoutDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("SizedBox设置具体尺寸示例"),
      ),
      body: SizedBox(
//        固定宽 200.0 高 300.0
        width: 200.0,
        height: 300.0,
        child: Card(
          child: Text(
            "SizedBox",
            style: TextStyle(fontSize: 36.0),
          ),
        ),
      ),
    );
  }
}