连续从流构建器中检索数据
我正在尝试用云燃烧器实现流构建器来检索现场数据。 这是代码：
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("test builder"),
),
body: StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance.collection('joystick').snapshots(),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot){
if(!snapshot.hasData){
return Center(
child: CircularProgressIndicator(),
);
}
return ListView.builder(
itemCount: snapshot.data?.docs.length,
itemBuilder: (context, i){
QueryDocumentSnapshot<Object?>? ds = snapshot.data?.docs[i];
return Text("$snapshot.data?.docs[i].data()!['call']");
});
}
),
);
}
但是，它不会输出数据库中存储的实际数据。 我将获得以下输出：
AsyncSnapshot<QuerySnapshot<Object?
>>(ConnectionState.active,Instance of '_JsonQuerySnapshot',null, null).data?.docs[i].data()!['call']
如何将数据存储在数据库中？ （字段名称为“呼叫”）
I am trying to implement stream builder with cloud firestore to retrieve field data.
Here is the code:
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("test builder"),
),
body: StreamBuilder<QuerySnapshot>(
stream: FirebaseFirestore.instance.collection('joystick').snapshots(),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot){
if(!snapshot.hasData){
return Center(
child: CircularProgressIndicator(),
);
}
return ListView.builder(
itemCount: snapshot.data?.docs.length,
itemBuilder: (context, i){
QueryDocumentSnapshot<Object?>? ds = snapshot.data?.docs[i];
return Text("$snapshot.data?.docs[i].data()!['call']");
});
}
),
);
}
However, it does not output the actual data stored in the database.
I get the following output:
AsyncSnapshot<QuerySnapshot<Object?
>>(ConnectionState.active,Instance of '_JsonQuerySnapshot',null, null).data?.docs[i].data()!['call']
What should I do to get the data stored in the database? (The field name is 'call')
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为了实现使用Cloud Firestore的流构建器来检索字段数据，您可以按照 noreferrer“> StreamBuilder文档和
如前所述， thread ，您可以在通过StreamBuilder检索数据时浏览以下代码：
，您可以参考文档已经解释了使用Cloud Firestore的更新。
In order to implement stream builder with cloud firestore to retrieve field data, you can follow the StreamBuilder Documentation and link related to explanation of streambuilder in flutter.
As mentioned the thread, you can go through the following code on retrieving data through streambuilder :
For more information, you can refer to the Documentation where real time updates with cloud firestore have been explained.
尝试此一个返回数据
Try this one to return your data
您正在尝试实现疑虑的实时数据库，而不是为此而制定Firestore数据库。
What you are trying to achieve concerns RealTime database, Firestore database is not made for that.