LoginConfig#onCreate.java

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_login);

        LoginConfig.init(this);

        mSaveUsernameView = (CheckBox) findViewById(R.id.save_username);    
        mSaveUsernameView.setVisibility(LoginConfig.getShowSaveUsername() ? View.VISIBLE : View.INVISIBLE);
    }