private void Start()
{
Debug.Log("start");
mediator = new ConcreteMediator();
panelA = new PanelA(mediator, "PanelA");
panelB = new PanelB(mediator, "PanelB");
mediator.AddUIPanel(panelA);
mediator.AddUIPanel(panelB);
mediator.NotifyHide("PanelB");
mediator.NotifyShow("PanelA");
Debug.Log("end");
}