如何将 FutureBuilder 代码转换为 StreamBuilder？

Question

我正在尝试从 Firestore 获取数据并使用流将该数据传递到屏幕。我使用 FutureBuilder 完成了此操作，此解决方案如下所示，但我需要使用 StreamBuilder 谁能帮我找到问题所在？

Future<List<Business>> list(FirebaseFirestore _firesore) async {
    CollectionReference _col = _firesore.collection('Buisiness');
    var _result = await _col.get();
    var _docs =  _result.docs;
    return List.generate(_docs.length, (index) {
      var satir = _docs[index].data();
      return Business.fromMap(satir as Map<String, dynamic>);
    });
  }

此代码适用于 FutureBuilder 但不适用于 StreamBuilder

 StreamBuilder<List<Business>>(
          stream: _firestorelist.list(_firestore), // Error Here
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              List<Business>? data = snapshot.data;
              return ListView.builder(
                itemCount: data!.length,
                itemBuilder: (context, index) {
                  var result = data[index];
                  return ListTile(
                    title: Text(result.nereden),
                    subtitle: Text(result.nereye),
                    trailing: Text(result.fiyat),
                  );
                },
              );
            } else {
              return CircularProgressIndicator();
            }
          },
        )```

Answer 1

当前方法是One-time Read方法，您可以从特定集合中获取快照。

您可以像这样更改方法，然后将其用作 streamBuilder 中的流：

list(FirebaseFirestore _firesore) async {
    CollectionReference _col = _firesore.collection('Buisiness');
    var _result = await _col.snapshots();
    return _result;
  }

Answer 2

你可以把你的数据源方法写成

Stream<List<Business>> list(FirebaseFirestore _firesore) {
  CollectionReference _col = _firesore.collection('Buisiness');

  final _snap = _col.snapshots();

  return _snap.map((event) => event.docs
      .map<Business>((e) => Business.fromMap(e.data() as Map<String, dynamic>))
      .toList());
}

如何将 FutureBuilder 代码转换为 StreamBuilder？

How can I convert FutureBuilder code to StreamBuilder?

flutter

dart

flutter-futurebuilder

flutter-streambuilder