作者:手机用户2502926851 | 来源:互联网 | 2022-12-10 12:34
我的Flutter应用出现问题,我有一个仅返回StreamBuilder的类,它运行良好,可以显示Cloud Firestore中的数据。但是,当我尝试将此类包装在Column或ListView类中时,它什么也没显示。
我需要它来显示当前页面的名称。而且AppBar类已经具有应用程序名称,因此我也不能使用它。
有谁知道我该如何包装并保持运行?
示例代码正常工作
class NewCardsList extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new StreamBuilder(
stream: firestore.collection('cards_list').snapshots(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (!snapshot.hasData) return const Text('Connecting...');
final int cardLength = snapshot.data.documents.length;
return new ListView.builder(
itemCount: cardLength,
itemBuilder: (int index) {
final DocumentSnapshot _card= snapshot.data.documents[index];
return new ListTile(
title: new Text(_card['title']),
subtitle: new Text(_card['description']),
);
},
);
},
);
}
}
示例代码不起作用
class NewCardsList extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new Column(
children: [
Text("Your Card List"),
StreamBuilder(
stream: firestore.collection('cards_list').snapshots(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (!snapshot.hasData) return const Text('Connecting...');
final int cardLength = snapshot.data.documents.length;
return new ListView.builder(
itemCount: cardLength,
itemBuilder: (int index) {
final DocumentSnapshot _card= snapshot.data.documents[index];
return new ListTile(
title: new Text(_card['title']),
subtitle: new Text(_card['description']),
);
},
);
},
]));
}
}
Rajesh Jr...
8
用Flexible()包装Streambuilder,然后用Column()包装Flexible,将column设置为scaffold()的主体
1> Rajesh Jr...:
用Flexible()包装Streambuilder,然后用Column()包装Flexible,将column设置为scaffold()的主体