UI控制類（所有按鈕點選時都將呼叫此類）：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class UIController : MonoBehaviour {

    public Button begin;
    public Button introduce;
    public Button member;
    public Button back;
    public Image image;
    public
 
 Sprite introSprite;
    public Sprite memberSprite;

    //返回開始介面，返回首頁按鈕點選時呼叫
    public void ReturnStartPage() {
        Application.LoadLevel(0);
    }
    //開始遊戲，開始遊戲及再玩一次按鈕點選時呼叫
    public void BeginGame() {
        Application.LoadLevel(1);//點選開始按鈕，進入第一關
    }
    //顯示遊戲介紹，遊戲介紹按鈕點選時呼叫
    public void Introduce
 
(bool show) {
        SetActiveState(show);
        image.GetComponent<Image>().sprite = introSprite;
    }
    //顯示小組成員，小組成員按鈕點選時呼叫
    public void Member(bool show) {
        SetActiveState(show);
        image.GetComponent<Image>().sprite = memberSprite;
    }
    //顯示開始介面，返回按鈕點選時呼叫
    public
 
 void Back(bool show) {
        SetActiveState(show);
    }

    //設定介面按鈕活動狀態
    void SetActiveState(bool show) {
        begin.gameObject.SetActive(show);
        introduce.gameObject.SetActive(show);
        member.gameObject.SetActive(show);
        back.gameObject.SetActive(!show);
        image.gameObject.SetActive(!show);
    }
}

待續。