Checking if a particular value exists in the Firebase database

Question

I am making an Android application using Firebase realtime database. When a new user registers on my app, that user\'s data is saved in the Firebase database. <

Answer 1

Check it like this...

    fdbRefer.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if(dataSnapshot.exist() {
//username exist
}
else {
//username doesn't exist
}
}
});