Can a value from the Database throw null because it does not have time to load the value?

Question

Java

We need to get the value in onCreate from the database, but for some reason it throws null all keys match the
database:

The code where all this happens:

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
         nick1 = findViewById(R.id.Nick);
         email1 = findViewById(R.id.Email);
         avatar1 = findViewById(R.id.avatar);


        DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
        DatabaseReference uidRef = rootRef.child("users").child(getUid());

        Log.i("deecode",getUid());
        ValueEventListener valueEventListener = new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                String nick = dataSnapshot.child("username").getValue(String.class);
                String email = dataSnapshot.child("account").getValue(String.class);
                String Avatar = dataSnapshot.child("GoogleAvatar").getValue(String.class);
                nick1.setText(nick);
                email1.setText(email);

            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        };
        uidRef.addListenerForSingleValueEvent(valueEventListener);

I get this exception

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference`

I'm trying to change these 2 TextViews - GreenCools,[email protected]
This is a separate layout nav_header_test.xml
Could this be causing this error?

Here is another Debug

This is how the xml looks like which I do setContentView

activity_test

Answer 1

Since they are in a separate layout, you need to initialize like this -

TextView nick1 = navigationView.getHeaderView(0).findViewById(R.id.NickMenuActivity);
        TextView email1 = navigationView.getHeaderView(0).findViewById(R.id.EmailMenuActivity);

Answer 2

It also writes to you that the textview is null. Check that the activity_test markup contains a textview with the IDs you are looking for.