CODEWITHSUNDEEP
androidfirebase
Parag Kadam
Parag Kadam

Reputation: 3850

How to synchronize firebase data?

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I am usingfirebase to store my data.This is how my firebase database looks like. In my code i am trying to generate a new unique appointment-id on button click event. If the current appointment-id is 88 then it should become 89 when the user presses the button on his app, and this appointment-id is assigned to him as his unique appointment-id. The problem that I am facing is that when two or more users press the button on their app at the same time, then the same appointment-id is assigned to both of them.

I want my appointment-id to be synchronized i.e only one user can access it at a time.Is this possible ? How can I achieve it? Thanks.

Upvotes: 2

Views: 1791

Answers (1)

David East
David East

Reputation: 32604

Firebase has transactions that will help you with incremental counters.

Firebase apptRef = new Firebase("<my-firebase-app>");
apptRef.runTransaction(new Transaction.Handler() {
    @Override
    public Transaction.Result doTransaction(MutableData currentData) {
        if(currentData.getValue() == null) {
            currentData.setValue(1);
        } else {
            currentData.setValue((Long) currentData.getValue() + 1);
        }
        return Transaction.success(currentData); //we can also abort by calling Transaction.abort()
    }
    @Override
    public void onComplete(FirebaseError firebaseError, boolean committed, DataSnapshot currentData) {
        //This method will be called once with the results of the transaction.
    }
});

Read the Firebase docs for more information.

Upvotes: 4

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