1

当我运行此代码时，ListView 将有一个意外的顶部填充。（见截图）为什么会这样，有没有办法避免这种情况？

我已经尝试过 SliverOverlapAbsorber、SafeArea 和 MediaQuery 来修复填充，但到目前为止似乎没有任何效果。

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  MyHomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: NestedScrollView(
        headerSliverBuilder: (context, innerBoxIsScrolled) => [
          SliverAppBar(
            pinned: true,
            title: Text('Title'),
          ),
        ],
        body: ListView.builder(
          itemCount: 24,
          itemBuilder: (context, index) => Container(
            height: 40,
            alignment: Alignment.center,
            color: Colors.yellow,
            margin: EdgeInsets.only(top: index != 0 ? 8 : 0),
            child: Text('Body $index'),
          ),
        ),
      ),
    );
  }
}

在此处输入图像描述

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4

3 回答 3

2

ListView添加一些默认填充，检查文档：

默认情况下，ListView 将自动填充列表的可滚动末端，以避免 MediaQuery 填充指示的部分障碍。为避免此行为，请使用零填充属性覆盖。

您可以通过在构建器中添加配置来轻松摆脱它padding，就像这样（您可以添加 0 但我不推荐它）：

body: ListView.builder(
  padding: const EdgeInsets.only(top: 8), // <-- add this line
  itemCount: 24,
  itemBuilder: (context, index) => Container(
    height: 40,
    alignment: Alignment.center,
    color: Colors.yellow,
    margin: EdgeInsets.only(top: index != 0 ? 8 : 0),
    child: Text('Body $index'),
  ),
),
于 2021-08-16T18:30:17.520 回答
2

如果您将 ListView 放在没有 appBar 的 Scaffold 内的某个位置，则 ListView 具有顶部填充。如果 appBar 存在，则没有填充。如果为 ListView 明确指定 EdgeInsets.zero 填充，则没有填充。

于 2021-08-16T18:31:29.230 回答
0

似乎没有办法避免手动删除填充。所以我的解决方案现在看起来像这样：

return Scaffold(
      body: DefaultTabController(
        length: 2,
        child: NestedScrollView(
          headerSliverBuilder: (context, innerBoxIsScrolled) => [
            SliverAppBar(
              pinned: true,
              title: Text('Title'),
              bottom: TabBar(tabs: [Tab(text: 'T 1'), Tab(text: 'T 2')]),
            ),
          ],
          body: MediaQuery.removePadding(
            removeTop: true,
            context: context,
            child: ListView.builder(
              itemCount: 24,
              itemBuilder: (context, index) => Container(
                height: 40,
                padding: EdgeInsets.zero,
                alignment: Alignment.center,
                color: Colors.yellow,
                margin: EdgeInsets.only(top: index != 0 ? 8 : 0),
                child: Text('Body $index'),
              ),
            ),
          ),
        ),
      ),
    );
于 2021-08-17T17:03:56.707 回答