Firebase variable not updating

Question

I'm a bit puzzled by strange problem.

I'm trying to access a value on a Firebase database.

final long[] time = {0};
    firebaseAuth = FirebaseAuth.getInstance();
        email = FirebaseAuth.getInstance().getCurrentUser().getEmail();
        DocumentReference docRef = db.collection("location_times").document(email);
        docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                if (task.isSuccessful()) {
                    DocumentSnapshot document = task.getResult();
                    if (document.exists()) {
                        Log.e(TAG, "DocumentSnapshot data: " + document.get("time"));
                        time[0] = (long) document.get("time");
                        Log.e(TAG, "Location frequency is " + time[0] + " seconds.");

                    } else {
                        Log.e(TAG, "No such document");
                    }
                } else {
                    Log.e(TAG, "get failed with ", task.getException());
                }
            }
        });

    Log.e(TAG, "Time is: " + time[0]);

The time variable is what I want to access.

The Logcat shows the following:

Location frequency is 5 seconds.
Time is: 0

What seems to be the problem? It seems to access the database fine, but the variable isn't updated. What am I doing wrong?

Thanks in advance!

In addition to @ManishParajapati's answer, see https://stackoverflow.com/a/46387410, https://stackoverflow.com/q/33203379, https://stackoverflow.com/a/38460676, https://stackoverflow.com/a/50435519 and quite a few more. — Frank van Puffelen, Nov 10 '18 at 15:16
Never thought this would be the problem. I'm still learning I guess :) Thanks! — dj.rodrigues, Nov 10 '18 at 15:30

ManishPrajapati · Accepted Answer · 2018-11-10T15:04:34.787

It is 0 because it is not updated yet, as firebase runs a async task to complete the listeners.

You are accessing Log.e(TAG, "Time is: " + time[0]); line of code outside onComplete listener. This line of code is executed before even the firebase has completed its fetching. You can implement a method call and access the Time from there.

final long[] time = {0};
firebaseAuth = FirebaseAuth.getInstance();
    email = FirebaseAuth.getInstance().getCurrentUser().getEmail();
    DocumentReference docRef = db.collection("location_times").document(email);
    docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
        @Override
        public void onComplete(@NonNull Task<DocumentSnapshot> task) {
            if (task.isSuccessful()) {
                DocumentSnapshot document = task.getResult();
                if (document.exists()) {
                    Log.e(TAG, "DocumentSnapshot data: " + document.get("time"));
                    time[0] = (long) document.get("time");
                    Log.e(TAG, "Location frequency is " + time[0] + " seconds.");
                    showTime(); // Added a method call
                } else {
                    Log.e(TAG, "No such document");
                }
            } else {
                Log.e(TAG, "get failed with ", task.getException());
            }
        }
    });

public void showTime(){ // perform your action after the firebase task is completed
Log.e(TAG, "Time is: " + time[0]);
}

I still have to access that variable *immediately* after the Firebase task. Where can I call that new method? — dj.rodrigues, Nov 10 '18 at 14:58
I have added a new method showTime() in onCompleteListener, it will call that method immediately once the firebase task is completed and your if condition is met. — ManishPrajapati, Nov 10 '18 at 15:03

Firebase variable not updating

1 Answers1