【菜菜丸的菜鸟教程】做一个简单的游戏截图相册（4）

四、相册已满时的提示

(1)制作提示窗口的UI

在这个项目中，我们一共需要三个弹出窗口，所以这里先新建UI>Canvas，命名为Popup Window Canvas，将所有弹出窗口都放到这个画布下。

在Popup Window Canvas下新建UI>Panel，重命名为Alert，按照之前介绍的方法设置大小、位置、背景图等。(参考大小：长600宽300)

在Alert下新建UI>Text，放到Alert偏上居中的位置，调整大小。(参考大小：长460宽180)在Text的Text组件中输入以下文字并调整字体、字号等：

相册已满！

请至少删除一张图片后再尝试截屏

在Alert下新建UI>Button，放到Alert偏下居中的位置，命名为Alert Btn，调整大小。在Alert Btn的子物体Text的Text组件中，输入文字“确定”，并调整字体、字号等。

完成后的提示窗口UI将类似于下图：

做完提示窗口UI后，取消勾选Alert，令其隐藏。

(2)当相册已满时，弹出提示窗口

这一步并不难，之前我们已经做完了截图功能，现在我们只需要加一个条件，也就是当已有截图数量小于相册格子数时才进行截图，否则就显示警告窗口。因为这里我们声明了一个公开的GameObject变量，所以记得写完脚本后要回到Inspector中，将Alert挂载到相应栏位。

public GameObject alertWindow;

void Start()
    {
        //给警告窗口的关闭按钮加上监听事件
        alertBtn.onClick.AddListener(CloseAlertWindow);
     }
void Update()
    {
        //按S键截图
        if (Input.GetKeyDown(KeyCode.S))
         {              
              //如果已有截图数量小于相册格子数，则进行截图
              if(fileCount < slots.Count)
              {
                StartCoroutine(CaptureScreenshot()); 
              }
              //如果已有截图数量大于相册格子数，则显示警告窗口
              else
              {
                  this.GetComponent<AlbumManager>().alertWindow.SetActive(true);
              }                                  
         }
    }

    //关闭警告窗口
    public void CloseAlertWindow()
    {
        alertWindow.SetActive(false);
    }

到这步为止的脚本如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;
using System;
using UnityEngine.UI;
using System.IO;
using UnityEditor;
using System.Linq;

public class AlbumManager : MonoBehaviour
{    
    private string folderPath;
    DirectoryInfo screenshotDir;
    private int screenshotCount = 0;
    static List<int> screenshotlist = new List<int>();
    private string screenshotFileName;
    private int fileCount = 0;
    Texture2D[] textures;
    Sprite[] sprites;
    String[] screenshotNames;
    String[] screenshotPaths;
    public List<GameObject> slots = new List<GameObject>();
    public GameObject album;
    public Button albumCloseBtn;
    bool isOpen = false;
    public Button albumCloseBtn;
    public GameObject alertWindow;

    void Start()
    {
        folderPath = Application.persistentDataPath + "/Textures/";
        screenshotDir = new DirectoryInfo(folderPath);
        if (!Directory.Exists(folderPath))
           Directory.CreateDirectory(folderPath);
         albumCloseBtn.onClick.AddListener(ShowOrHideAlbum);
         screenshotlist.Add(screenshotCount);
        screenshotCount = PlayerPrefs.GetInt("MaxNumber"); 
         albumCloseBtn.onClick.AddListener(ShowOrHideAlbum);
         alertBtn.onClick.AddListener(CloseAlertWindow);
         ReplaceImages();
     }             

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.A))
        {
            ShowOrHideAlbum();
        }
        if (Input.GetKeyDown(KeyCode.S))
         {              
              if(fileCount < slots.Count)
              {
                StartCoroutine(CaptureScreenshot()); 
              }
              else
              {
                  this.GetComponent<AlbumManager>().alertWindow.SetActive(true);
              }                                  
         }
     }

    private IEnumerator CaptureScreenshot()
     {
          screenshotCount ++;
          screenshotlist.Add(screenshotCount);
          PlayerPrefs.SetInt("MaxNumber", screenshotlist.Max());
          screenshotFileName = "Screenshot_" + screenshotCount + ".png";
          ScreenCapture.CaptureScreenshot(folderPath + screenshotFileName); 
          yield return new WaitForSeconds(0.5f);
        #if UNITY_EDITOR
          AssetDatabase.Refresh();
        #endif
     }

    public void CreateSprites()
    {
        FileInfo[] screenshotFiles = screenshotDir.GetFiles("*.png");
        fileCount = screenshotDir.GetFiles("*.png").Length;
        Array.Resize(ref textures, fileCount);
        Array.Resize(ref sprites, fileCount);
        Array.Resize(ref screenshotNames, fileCount);
        Array.Resize(ref screenshotPaths, fileCount);
        for (int i = 0; i < fileCount; i++)
        {           
            textures[i] = new Texture2D (256, 256);
            screenshotPaths[i] = screenshotFiles[i].FullName;
            screenshotNames[i] = screenshotFiles[i].Name;
            byte[] rawPNG = File.ReadAllBytes(screenshotPaths[i]); 
            textures[i].LoadImage(rawPNG); 
            sprites[i] = Sprite.Create(textures[i], new Rect(0f, 0f, textures[i].width, textures[i].height), Vector2.zero, 100.0f);
            sprites[i].name = "Sprite" + i;
        }
    }

    public void ReplaceImages()
    {
        CreateSprites();
         for (int j = 0; j < slots.Count; j++)
        {
            slots[j].transform.GetChild(0).gameObject.GetComponent<Image>().sprite = null;
            slots[j].transform.GetChild(0).gameObject.SetActive(false);
        }
        for (int i = 0; i < sprites.Length; i++)
        {            
            if (slots[i].transform.GetChild(0).gameObject.activeInHierarchy == false)                
            {
                slots[i].transform.GetChild(0).gameObject.SetActive(true);
                slots[i].transform.GetChild(0).gameObject.GetComponent<Image>().sprite = sprites[i];       
            }      
        }        
    }

    public void ShowOrHideAlbum()
    {
        isOpen = !isOpen;
        album.SetActive(isOpen);
    }

    public void CloseAlertWindow()
    {
        alertWindow.SetActive(false);
    }