public void OpenPrompt(PromptWindowAction confirmAction, PromptWindowAction cancelAction, string title, string content)
 {
     gameObject.SetActive(true);
     titleText.text   = title;
     contentText.text = content;
     confirm         += confirmAction;
     cancel          += cancelAction;
 }
 void ClearAction()
 {
     foreach (Delegate d in confirm.GetInvocationList())
     {
         confirm -= (PromptWindowAction)d;
     }
     foreach (Delegate d in cancel.GetInvocationList())
     {
         cancel -= (PromptWindowAction)d;
     }
 }