Facebook login successful but firebase auth throw exception

Question

Im new of firebase and I want to implement the facebook auth for the first time . I can getting facebook token succesfully but when I call signInWithCredential() ide throw this exception .

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.tasks.Task com.google.android.gms.common.api.GoogleApi.zzb(com.google.android.gms.common.api.internal.zzdf)' on a null object reference

Here is my source code

public class LoginActivity extends AppCompatActivity {

    private CallbackManager callbackManager;
    private FirebaseAuth mAuth;
    private String TAG = "Test";

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mAuth = FirebaseAuth.getInstance();
        callbackManager = CallbackManager.Factory.create();

        LoginButton loginButton = (LoginButton) findViewById(R.id.login_button);
        loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {

                handleFacebookAccessToken(loginResult.getAccessToken());


            }

            @Override
            public void onCancel() {


            }

            @Override
            public void onError(FacebookException e) {

            }
        });

    }

    private void handleFacebookAccessToken(AccessToken token) {

        AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
        mAuth.signInWithCredential(credential)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {

                            FirebaseUser user = mAuth.getCurrentUser();

                        } else {

                        }

                    }
                });
    }

    @Override
    public void onStart() {
        super.onStart();
        FirebaseUser currentUser = mAuth.getCurrentUser();

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        callbackManager.onActivityResult(requestCode, resultCode, data);
    }
}

thanks for any suggestion .

Answer 1

You must have Google Play Services installed. I suppose you are testing it on the Emulator. Try testing it on a real device or make sure you have GPS installed on your emulator

Answer 2

Please check your FirebaseUI and Firebase / Play Services versions. They have to match according to the table you can find here: https://github.com/firebase/FirebaseUI-Android