Flutter Firebase RTDB onValue 多次触发

Question

I'm developing an app which needs live data from the database which was created using Firebase RTDB. I used onValue to get the live data, the problem is that the onValue is triggered multiple times when a lot of data changed at once and messed up my data processing system. Been trying to look for solutions, but still haven't managed to find one. Any help will be appreciated. Here's the code:

await refConnection
        .child(user!.uid).orderByChild('date_created').onValue.forEach((element) {
          if (element.snapshot.value != null) {
            Map<dynamic, dynamic> connection = element.snapshot.value as Map<
                dynamic,
                dynamic>;
            print("Test: $connection");
            

            connection.forEach((key, value) {
              if (connection[key]['status'] == 'connected') {
                Provider.of<ContactDataProvider>(context, listen: false)
                    .addConnected(connection[key]);
              } else if (connection[key]['status'] == 'incoming_req') {
                Provider.of<ContactDataProvider>(context, listen: false)
                    .addIncoming(connection[key]);
              } else if (connection[key]['status'] == 'sent_req') {
                print(connection[key]);
                Provider.of<ContactDataProvider>(context, listen: false)
                    .addSent(connection[key]);
              }
            });

            setState();
          }
    });

Answer 1

Do you really need to listen for live updates? If not, then try getting the value only once using get() .

Solution: Trying with a different approach

Answer 2

Can you please provide an example about your user child structure?

As I can determine by your code, do you have multiple items with different data inside your user child, each data with a field called status ?

If that is correct, then you should use onChildChanged listener to list only when a child inside userId is changed.

That will be triggered when any child inside userId change its value, then you can verify if the childChanged.key == status then do your logic

But keep aware of the fact that any value changed inside userId child, will trigger your listener.

avoid cyclic calls