Retrieving specific data from Firebase Database

Question

I\'m creating a chat app on android using Firebase Database and Java. Whenever the user is first registered, it stores their username into the database under the nodes use

Answer 1

You aren't getting the value properly. You need to attach a listener to you child and get updates. You do that like this:

// Get a reference to your user
final FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("server/path/to/profile");

// Attach a listener to read the data at your profile reference
ref.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        Profile profile = dataSnapshot.getValue(Profile.class);
        System.out.println(profile.getUsername());
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        System.out.println("The read failed: " + databaseError.getCode());
    }
});

You can find more information and examples on the Firebase website. Keep in mind that you don't make requests to get data from Firebase. You attach listeners to the children and then get the data from the listener. This example assumes that you have a Profile model, with a method to get the username. This would return your Profile object and would enable you to get whatever data you need off of that object.