颤振 | ExpansionTile 属性 "children" 在展开时引发底部溢出问题

Question

我正在构建一个从 Firestore 中获取的项目列表，这些项目包装在 ListView.builder() 中的 ExpansionTile 中。数据被正确获取。那里没有问题。我可以看到这些项目的列表。

问题出在 Tile 扩展上，我需要显示一些 ListTile。但是在展开时，它给我一个 Bottom Overflowed by X pixels。

为了解决这个问题，我尝试将它包装在 ListView 中，但它抛出异常 -

Another exception was thrown: NoSuchMethodError: The method '<=' was called on null.

运气不好。

我正在编写这样的代码 -

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';

class NewExpansionPanel extends StatefulWidget {
  @override
  _NewExpansionPanelState createState() => _NewExpansionPanelState();
}

class _NewExpansionPanelState extends State<NewExpansionPanel> {
  Widget getListOfTexts(){
    return ListView(
      children: <Text>[
        Text('one'),
        Text('two'),
        Text('three'),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
      stream: Firestore.instance.collection(*someCollection*).snapshots(),
      builder: (context, snapshot) {
        if(!snapshot.hasData) return const Text("Loading.....");

        return ListView.builder(
          itemExtent: 80.0,
          itemCount: snapshot.data.documents.length,
          itemBuilder: (context, index) {
            final DocumentSnapshot document = snapshot.data.documents[index];
            return new ExpansionTile(
              children: [
                getListOfTexts()
              ],
              title: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  Text(
                    document['something'] ?? ' ',
                  ),
                  Text(document['title'] ?? '<No title retrieved>'),
                ],
              ), 
              onExpansionChanged: (bool isExpanded) {
                // put some code here in future
              },
            );
          }
        );
      }
    );
  }
}

Answer 1

您是否尝试在没有 ListView 的情况下直接使用 ExpansionTile 子文本？是这样的...

       ...//      
    return new ExpansionTile(
          children: [
            Text('one'),
            Text('two'),
            Text('three'),
          ],
        ...

或者对文本使用 ListTile..

return new ExpansionTile(
                children: [
                  ListTile(title: Text('one'),),
                  ListTile(title: Text('Two'),),
                  ListTile(title: Text('Three'),),           
                 ],

Answer 2

这很尴尬。我只需要删除 ListView.builder 上的 itemExtent: 80.0 属性。这导致了 Bottom Overflowed 问题。

颤振 | ExpansionTile 属性 "children" 在展开时引发底部溢出问题

Flutter | ExpansionTile property "children" throws a Bottom Overflowed issue on expanding

listview

widget

expansion

flutter