Unity 双击Esc或者返回退出游戏,有文字提示

第一次点击Esc或者返回,显示提示文字"再次按下返回键退出游戏",在文字消失之前再次点击Esc或者返回,退出游戏.

此脚本挂在Text文字提示上:

 1 using UnityEngine;
 2 using System.Collections;
 3 using UnityEngine.UI;
 7 public class ExitGame : MonoBehaviour
 8 {
 9     [Tooltip("ExitMessage拖进来")]
10     Text ExitMessageObj;
11     float fadingSpeed = 1;
12     bool fading;
13     float startFadingTimep;
14     Color originalColor;
15     Color transparentColor;
16     string sss;
17 
18     void Start()
19     {
20         ExitMessageObj = this.GetComponent<Text>();
21         originalColor = ExitMessageObj.color;
22         transparentColor = originalColor;
23         transparentColor.a = 0;
24         ExitMessageObj.text = "再次按下返回键退出游戏";
25         ExitMessageObj.color = transparentColor;
26     }
27 
28     void Update()
29     {
30         if (Input.GetKeyDown(KeyCode.Escape))
31         {
32             if (startFadingTimep == 0)
33             {
34                 ExitMessageObj.color = originalColor;
35                 startFadingTimep = Time.time;
36                 fading = true;
37             }
38             else
39             {               44                 Application.Quit();//退出游戏
45             }
46         }
47         if (fading)
48         {
49             ExitMessageObj.color = Color.Lerp(originalColor, transparentColor, (Time.time - startFadingTimep) * fadingSpeed);
50             if (ExitMessageObj.color.a < 2.0 / 255)
51             {
52                 ExitMessageObj.color = transparentColor;
53                 startFadingTimep = 0;
54                 fading = false;
55             }
56         }
57     }
58 }