MainActivity.java

public class MainActivity extends AppCompatActivity {

    CallbackManager callbackManager;
    TextView txtEmail, txtBirthday, txtFriends, txtLocation;
    ProgressDialog mDialog;
    ImageView imgAvatar;

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