I wonder why Android Fragment is slow in the initial call. [Material door]

public class a {

   private static int[] idLayoutMenuButtonNumber = {
            R.id.idButton_a,
            R.id.idButton_b,
            R.id.idButton_c,
            R.id.idButton_d,
            R.id.idButton_e,
    };
    public static Button[] idLayoutMenuButton = new Button[idLayoutMenuButtonNumber.length];

    public static   Menu_a            menu_a;
    public static   Menu_b             menu_b;
    public static   Menu_c              menu_c;
    public static   Menu_d             menu_d;
    public static   Menu_f           menu_f;

    public static Menu_Base menuSystemInstances[] = null;


    int selectedMainMenuIndex,

    final static int MAIN_MENU_NONE             = -1;
    final static int MAIN_MENU_a          = 0;
    final static int MAIN_MENU_b           = 1;
    final static int MAIN_MENU_c            = 2;
    final static int MAIN_MENU_d           = 3;
    final static int MAIN_MENU_e         = 4;
    final static int MAIN_MENU_f         = 5;   

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

        MenuButtonDefine(idLayoutMenuButton, idLayoutMenuButtonNumber);

        menu_a            =       new Menu_a();
        menu_b             =       new Menu_b();
        menu_c              =       new Menu_c();
        menu_d             =       new Menu_d();
        menu_e           =       new Menu_e();
        menu_f         =       new Menu_f();


        menuSystemInstances = new Menu_Base[] {
                menu_a,
                menu_b,
                menu_c,
                menu_d,
                menu_e,
                menu_f,
        };

        SYSTEM_NENU_MAIN_NUM = menuSystemInstances.length;
        selectedMainMenuIndex = MAIN_MENU_NONE;

    }

     public void MenuButtonDefine(final Button[] idLayoutMenuButton, int[] idLayoutMenuButtonNumber) {
        idImageButton_Exit = findViewById(R.id.idImageButton_Exit);
        idImageButton_Exit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                _Adpater_Menu.setVisibility(View.GONE);
                selectedMainMenuIndex = MAIN_MENU_NONE;
            }
        });

        for(int i = 0 ; i < idLayoutMenuButton.length ; i++ ) {
            idLayoutMenuButton[i] = findViewById(idLayoutMenuButtonNumber[i]);
            idLayoutMenuButton[i].setOnClickListener(this);
            idLayoutMenuButton[i].setOnTouchListener(this);
        }
    }

public void selectSubMenu(int index){
        String subMenuTitleName[] = { "a", "b", "c", "d", "e", "f" };

        idLayoutMenuButton[selectedMainMenuCursor].setSelected(false);
        selectedMainMenuCursor = index;
        idLayoutMenuButton[selectedMainMenuCursor].setSelected(true);

        selectedMainMenuIndex = index;

        idLayoutTOP_TITLEName.setText(subMenuTitleName[selectedMainMenuIndex]);

        idLayoutMenuButton[saveMenuPosition].setBackgroundColor(Color.TRANSPARENT);
        idLayoutMenuButton[saveMenuPosition].setTextColor(Color.WHITE);

        switch(selectedMainMenuIndex){
            case MAIN_MENU_a          :
                saveMenuPosition = MAIN_MENU_a;
                getFragmentManager().beginTransaction().replace(R.id.idLayoutCNETER_SettingName, menu_a).addToBackStack(null).commit(); break;
            case MAIN_MENU_b           :
                saveMenuPosition = MAIN_MENU_b;
                getFragmentManager().beginTransaction().replace(R.id.idLayoutCNETER_SettingName, menu_b).addToBackStack(null).commit(); break;
            case MAIN_MENU_c            :
                saveMenuPosition = MAIN_MENU_c;
                getFragmentManager().beginTransaction().replace(R.id.idLayoutCNETER_SettingName, menu_c).addToBackStack(null).commit(); break;
            case MAIN_MENU_d           :
                saveMenuPosition = MAIN_MENU_d;
                getFragmentManager().beginTransaction().replace(R.id.idLayoutCNETER_SettingName, menu_d).addToBackStack(null).commit(); break;
            case MAIN_MENU_e         :
                saveMenuPosition = MAIN_MENU_e;
                getFragmentManager().beginTransaction().replace(R.id.idLayoutCNETER_SettingName, menu_e).addToBackStack(null).commit(); break;
            case MAIN_MENU_f       :
                saveMenuPosition = MAIN_MENU_f;
                getFragmentManager().beginTransaction().replace(R.id.idLayoutCNETER_SettingName, menu_f).addToBackStack(null).commit(); break;
        }
    }
}