求助：flutter Column 高度自适应问题？

Question

在Column中通过设置mainAxisSize: MainAxisSize.min可以使Column自适应子节点的高度，例如：

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        body: Container(
            color: Colors.red,
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: const [
                Text('text'),
              ],
            )),
      ),
    );
  }
}

效果图：

但是如果放在TabBarView下面的话，就没用了，会填满整个屏幕，示例代码：

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        body: DefaultTabController(
          length: 2,
          child: Scaffold(
            appBar: PreferredSize(
                preferredSize: const Size.fromHeight(56),
                child: AppBar(
                  bottom: TabBar(
                    tabs: [
                      Tab(
                        text: "tab1",
                      ),
                      Tab(
                        text: "tab2",
                      ),
                    ],
                  ),
                )),
            body: TabBarView(
              children: [
                Container(
                    color: Colors.red,
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: const [
                        Text('text'),
                      ],
                    )),
                Container(
                  color: Colors.blue,
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: const [
                      Text('text'),
                    ],
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

效果图：

这种情况下要怎么才能让Column的高度自适应呢？

Answer 1

TabbarView下的widget默认会包一曾Expanded, 所以你的Container的确是占满屏幕的，可是Column不影响吧？
Column下的MainAxisSize.min还是会生效的。