Problem with read from Firebase Database, i can't save the data. Android - Java

Asked Jul 29 '20 at 12:46

Active Jul 29 '20 at 14:46

Viewed 25 times

i have a problem with this function. In "onDataChange" shows me the User, but i can't save him in an array for example. I put some comments in code to help understand. Sorry for my bad english.

    public User readUserFromDatabase(final String uid) {
        final User[] userr = new User[1];
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                User user = snapshot.child("users").child(uid).getValue(User.class);
                userr[0] = user;
                // Here shows me the user from database, correctly.
                Log.d(TAG, "onDataChange: " + userr[0]);
            }
            @Override
            public void onCancelled(@NonNull DatabaseError error) { }
        });
        // Here shows me null.
        Log.d(TAG, "readUserFromDatabase: " + userr[0]);

        return userr[0];
    }

asked Jul 29 '20 at 12:46

Zubii

have you check by debugging?, is onDataChange is called? – Nirav Bhavsar Jul 29 '20 at 12:53
These are the async functions you cannot return like this. You can not work outside of onDataChange function. Whatever you want to do inside it. – Vishal Pawar Jul 29 '20 at 13:07
@VishalPawar and how can i save the data ? – Zubii Jul 29 '20 at 13:10
Firebase API is asynchronous. So please check the duplicate to see how can you solve this using a custom callback. – Alex Mamo Jul 29 '20 at 13:12

Problem with read from Firebase Database, i can't save the data. Android - Java

0 Answers0