[英]How to combine to different firebase query streams into one stream?
我在尝试创建聊天应用程序时遇到了障碍。 我想将两个不同的流合并为一个,以创建我的聊天屏幕。 例如-
如果user1
向user2
发送消息,它将被存储在 -
FirebaseFirestore.instance.collection("users").doc(user1).collection("data").doc(user2).collection("chats")
同样,如果user2
向user1
发送消息,它会存储在 -
FirebaseFirestore.instance.collection("users").doc(user2).collection("data").doc(user1).collection("chats")
用户发送的所有聊天都存储在聊天集合中,位于名为接收者 uid 的文档中。
所以本质上,我需要数据 insede- FirebaseFirestore.instance.collection("users").doc(user1).collection("data").doc(user2).collection("chats")
(发送聊天由 user1 发送给 user 2) 和FirebaseFirestore.instance.collection("users").doc(user1).collection("data").doc(user2).collection("chats")
(获取 user2 发送给 user1 的聊天记录) 创建聊天屏幕。
我想知道如何将这两个流合并为一个,这样我就可以使用这些数据来创建聊天小部件。 到目前为止,这就是我所拥有的-
注意:继续类比, user1
的 uid 是FirebaseAuth.instance.currentUser..uid
,而user2
的 uid 存储在widget.uid
中。
StreamBuilder(
//To get messaages sent by the current user to user2 or widgets.uid
stream: FirebaseFirestore.instance
.collection("users")
.doc(FirebaseAuth.instance.currentUser!.uid)
.collection("data")
.doc(widget.uid)
.collection("chats")
.snapshots(),
builder: (context,
AsyncSnapshot<QuerySnapshot<Map<String, dynamic>>>
UserMessagesSnapshots) {
if (UserMessagesSnapshots.connectionState ==
ConnectionState.waiting) {
return const LoadingScreen();
} else {
return StreamBuilder(
//to get messages sent by user2 to user1
stream: FirebaseFirestore.instance
.collection("users")
.doc(widget.uid)
.collection("data")
.doc(FirebaseAuth.instance.currentUser!.uid)
.collection("chats")
.snapshots(),
builder: (context,
AsyncSnapshot<QuerySnapshot<Map<String, dynamic>>>
FriendMessagesSnapshot) {
if (FriendMessagesSnapshot.connectionState ==
ConnectionState.waiting) {
return const LoadingScreen();
} else {
//and here i have both the streams.
}
});
}
},
),
谢谢@mariofrancios!
我创建了这个 function 将流合并到一个-
Stream<List<QuerySnapshot>> getMessages() {
Stream userMessages = FirebaseFirestore.instance
.collection("users")
.doc(FirebaseAuth.instance.currentUser!.uid)
.collection("data")
.doc(widget.uid)
.collection("chats")
.snapshots();
Stream friendMessages = FirebaseFirestore.instance
.collection("users")
.doc(widget.uid)
.collection("data")
.doc(FirebaseAuth.instance.currentUser!.uid)
.collection("chats")
.snapshots();
return StreamZip([(userMessages as dynamic), (friendMessages as dynamic)]);
}
然后像这样听着——
...StreamBuilder(
stream: getMessages(),
builder: (context, AsyncSnapshot<List<QuerySnapshot>> snap) {
if (snap.connectionState == ConnectionState.waiting) {
return const LoadingScreen();
} else {
// access the data with snap.data![n].docs[n].data()
}
},
),
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