Question

我正在尝试从 firebase 数据库的集合构建一个列表，但我遇到了流构建器快照的问题。

StreamBuilder<QuerySnapshot>(
          stream: FirebaseFirestore.instance.collection("users").snapshots().where((event) => true),
          builder: (context, snapshot) {
            if (snapshot.hasData && snapshot.data != null) {
              return ListView.builder(
                itemBuilder: (listContext, index) =>
                    buildItem(snapshot.data.docs[index]),
                itemCount: snapshot.data.docs.length,
              );
            }

            return Container();
          },
        ));
  }

  buildItem(doc) {
    return (userId != doc['id'])
        ? GestureDetector(
      onTap: () {
        //Navigator.push(context, MaterialPageRoute(builder: (context) => Page(docs: doc)));
      },
      child: Card(
        color: Colors.black,
        child: Container(
          height: 60,
          child: Center(
            child: Text(doc['name'],
              style: TextStyle(
                color: Colors.white,
                fontSize: 20,
              ),
            ),
          ),
        ),
      ),
    )
        : Container();
  }

这是整个错误：

======== Exception caught by widgets library =======================================================
The following StateError was thrown building:
Bad state: field does not exist within the DocumentSnapshotPlatform

When the exception was thrown, this was the stack: 
#0      DocumentSnapshotPlatform.get._findKeyValueInMap (package:cloud_firestore_platform_interface/src/platform_interface/platform_interface_document_snapshot.dart:86:7)
#1      DocumentSnapshotPlatform.get._findComponent (package:cloud_firestore_platform_interface/src/platform_interface/platform_interface_document_snapshot.dart:104:41)
#2      DocumentSnapshotPlatform.get (package:cloud_firestore_platform_interface/src/platform_interface/platform_interface_document_snapshot.dart:120:26)
#3      _JsonDocumentSnapshot.get (package:cloud_firestore/src/document_snapshot.dart:92:48)
#4      _JsonDocumentSnapshot.[] (package:cloud_firestore/src/document_snapshot.dart:96:40)
...
====================================================================================================

构建器正在构建列表，但在其正下方给出了一个红色错误部分。

Answer 1

您的 doc 方法中的 buildItem 是一个 DocumentSnapshot object，据我所知，它没有定义 []。

我认为您错过了给 data() 的电话：

userId != doc.data()['id']

如果您在此更改后收到另一条错误消息，请先在 Stack Overflow 上搜索它，因为我知道最近在如何从文档快照中公开类型方面发生了一些变化。

错误状态：DocumentSnapshotPlatform 中不存在字段。颤振和火力基地

1 个答案: