Question

我正在尝试构建一个布局，在该布局的顶部和底部有两个Text对象，这些对象保留了文具，而ListView处于它们的中心。

这是屏幕的代码

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Container(
          padding: EdgeInsets.symmetric(horizontal: 40.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              Container(
                margin: EdgeInsets.symmetric(vertical: 40.0),
                child: Text(
                  DateFormat("hh:mm 'PM ,'  MMMM d").format(DateTime.now()),
                  style: Theme.of(context).textTheme.title,
                ),
              ),
              Expanded(
                child: ListView.builder(
                  itemCount: 4,
                  itemBuilder: (BuildContext context, int index) =>
                      CustomAppText(
                        text: 'Custom App',
                      ),
                ),
              ),
              Container(
                margin: EdgeInsets.symmetric(vertical: 40.0),
                child: Text(
                  "Settings",
                  style: Theme.of(context).textTheme.title,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

给定代码的输出

我正在寻找的设计

我尝试使用Center小部件，但它没有将ListView居中

Answer 1

ListView填满了整个Expanded Widget，这就是为什么使用Center Widget无法正常工作的原因，因此应添加shrinkWrap: true，以便ListView仅占据其子级的高度。

浏览了文档后，我发现了有关Flexible Widget的信息

Flexible, which does not force the child to fill the available space.

进行更改并像魅力一样工作

Flexible(
                child: ListView.builder(
                  shrinkWrap: true,
                  itemCount: 4,
                  itemBuilder: (BuildContext context, int index) =>
                      CustomAppText(
                        text: 'Custom App',
                      ),
                ),
              ),

Answer 2

对于那些仍在寻找答案的人，这对我有用：

Column(
  children: [

    Container(), // some top content

    Expanded(
      child: Center(
        child: ListView(
          shrinkWrap: true,
          children: [] //your list view content here
        )
      )
    ),

    Container(), // some bottom content

  ]
)

扩展小部件使内容占用所有可用空间。

中心小部件将要显示的内容居中。

ListView 保存您的列表内容，而“ shrinkWrap：true” 属性使您的列表视图根据内容大小缩小（允许通过居中小部件时）。

Answer 3

如果您将public class Ride { @Column(name = "start_time") private LocalDateTime startTime; @Column(name = "end_time") private LocalDateTime endTime; }小部件替换为select ayr,mods.mid,mtitle,credits from mods,comp where mods,mid = comp.mid and ayr = '2001/02';，并给它固定的Expanded，我想您就会找到所需的内容。

Answer 4

只需在Expanded内添加第一个Container的包装Column

        Expanded(
                        child: Container(
                          margin: EdgeInsets.symmetric(vertical: 40.0),
                          child: Text(
                            DateFormat("hh:mm 'PM ,'  MMMM d").format(DateTime.now()),
                            style: Theme.of(context).textTheme.title,
                          ),
                        ),
                      ),

Answer 5

希望有帮助。为顶部和底部小部件提供屏幕尺寸的25％。给listview屏幕大小的50％。

import 'package:flutter/material.dart';

class TestPage extends StatefulWidget {
  @override
  _TestPageState createState() => _TestPageState();
}

class _TestPageState extends State<TestPage> {
  @override
  Widget build(BuildContext context) {
    final _size = MediaQuery.of(context).size;

    return Scaffold(
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.all(28.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              // Top Widgets
              Container(
                width: double.infinity,
                // color: Colors.green,
                height: _size.height * 0.25, // Take 25% width of the screen height
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.start,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Text('11: 25 AM', style: TextStyle(fontSize: 23.0),),
                    Text('Set As Launcher', style: TextStyle(fontSize: 23.0),)
                  ],
                ),
              ),

              Expanded(
                child: Container(
                  // color: Colors.yellow,
                  child: ListView(
                    children: List.generate(25, (index){
                      return Text('Custom App $index', style: TextStyle(fontSize: 45.0),);
                    }),
                  ),
                ),
              ),

              // Bottom Widgets
              Container(
                width: double.infinity,
                // color: Colors.blue,
                height: _size.height * 0.25, // Take 25% width of the screen height
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.end,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Text('Settings', style: TextStyle(fontSize: 23.0),),                    
                  ],
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

Answer 6

只需将ListView.builder包装在容器类中，然后将其高度显式地加倍或以屏幕高度的百分比即可。

class Trial extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Container(
          padding: EdgeInsets.symmetric(horizontal: 40.0),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              Container(
                margin: EdgeInsets.symmetric(vertical: 40.0),
                child: Text(
                  "Some Text",
                  style: Theme.of(context).textTheme.title,
                ),
              ),
              Container(
//                height: 40,
                height: MediaQuery.of(context).size.height * 0.4,
                child: ListView.builder(
                  itemCount: 20,
                  itemBuilder: (BuildContext context, int index) {
                    return Text("Hello");
                  }
                ),
              ),
              Container(
                margin: EdgeInsets.symmetric(vertical: 40.0),
                child: Text(
                  "Settings",
                  style: Theme.of(context).textTheme.title,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

Answer 7

添加两个垫片，它会给你 100% 与你预期相同的结果

      Spacer(),
          Expanded(
            child: ListView.builder(
              itemCount: 4,
              itemBuilder: (BuildContext context, int index) =>
                  CustomAppText(
                    text: 'Custom App',
                  ),
            ),
          ),
          Spacer(),

列颤振内部居中扩展ListView

7 个答案: