Question 120077 in Firebase Question posted in
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Firebase – How to run async function once in streambuilder

I have a streambuilder that Im trying to call a function that updates the read status on my app

void readMessage() async {
int num = 0;
final query = await FirebaseFirestore.instance
    .collection('chats')
    .doc(chatroomId(FirebaseAuth.instance.currentUser!.uid, widget.uid))
    .collection('messages')
    .where('uid', isEqualTo: widget.uid)
    .where('read', isEqualTo: false)
    .get();

query.docs.forEach((doc) {
  doc.reference.update({'read': true});
});

num = query.docs.length;

await FirebaseFirestore.instance
    .collection('users')
    .doc(FirebaseAuth.instance.currentUser!.uid)
    .update(
  {"messagesNotification": FieldValue.increment(-num)},
);
}

and in my streambuilder im trying

return Container(
      child: StreamBuilder(
        stream: FirebaseFirestore.instance
            .collection('chats')
            .doc(chatRoom)
            .collection('messages')
            .orderBy('createdAt', descending: true)
            .snapshots(),
        builder: (context,
            AsyncSnapshot<QuerySnapshot<Map<String, dynamic>>> snapshot) {
          readMessage();

The issue is that it seems to be running twice, so if for example they have 3 unread messages its decreasing the message counter by 3 then 3 again. Im also not sure if this is how it works but am I right in believing that if a new message appeared in the stream it will run that method everytime so that incoming messages are marked as read when the stream is open?

Tags:

2

Answers


  1. 0

    StreamBuilder widget rebuilds the ui with every change with the stream, so you need to wrap your readMessage() with conditional statement to decide whether to run this function or not

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  2. 0

    You could create a boolean to check if the function is called

    bool functionCalled = false;

    Check if the function is called and if not you do your logic and inside it you set it to true. The next call won’t jump in the if.

    if(!functionCalled){
functionCalled = true;
int num = 0;
final query....
}
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