93 lines
2.7 KiB
C#
93 lines
2.7 KiB
C#
using UnityEngine;
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using UnityEngine.UI;
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using System.Collections;
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using System.IO;
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public class AsyncImageDownload : MonoBehaviour
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{
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public Sprite myWXPic;
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private static AsyncImageDownload _instance = null;
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public static AsyncImageDownload GetInstance()
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{ return Instance; }
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public static AsyncImageDownload Instance
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{
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get
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{
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if (_instance == null)
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{
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GameObject obj = new GameObject("AsyncImageDownload");
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_instance = obj.AddComponent<AsyncImageDownload>();
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DontDestroyOnLoad(obj);
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_instance.Init();
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}
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return _instance;
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}
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}
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public bool Init()
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{
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if (!Directory.Exists(Application.persistentDataPath + "/ImageCache/"))
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{
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Directory.CreateDirectory(Application.persistentDataPath + "/ImageCache/");
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}
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myWXPic = null;
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return true;
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}
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public void SetAsyncImage(string url, Image image)
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{
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//开始下载图片前,将UITexture的主图片设置为占位图
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if (myWXPic != null)
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{
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image.sprite = myWXPic;
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return;
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}
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//判断是否是第一次加载这张图片
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if (!File.Exists(path + url.GetHashCode()))
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{
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//如果之前不存在缓存文件
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StartCoroutine(DownloadImage(url, image));
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}
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else
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{
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StartCoroutine(LoadLocalImage(url, image));
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}
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}
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IEnumerator DownloadImage(string url, Image image)
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{
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Debug.Log("downloading new image:" + path + url.GetHashCode());//url转换HD5作为名字
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WWW www = new WWW(url);
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yield return www;
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Texture2D tex2d = www.texture;
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//将图片保存至缓存路径
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byte[] pngData = tex2d.EncodeToPNG(); //将材质压缩成byte流
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File.WriteAllBytes(path + url.GetHashCode(), pngData); //然后保存到本地
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Sprite m_sprite = Sprite.Create(tex2d, new Rect(0, 0, tex2d.width, tex2d.height), new Vector2(0, 0));
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image.sprite = m_sprite;
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myWXPic = m_sprite;
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}
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IEnumerator LoadLocalImage(string url, Image image)
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{
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string filePath = "file:///" + path + url.GetHashCode();
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WWW www = new WWW(filePath);
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yield return www;
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Texture2D texture = www.texture;
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Sprite m_sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0, 0));
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image.sprite = m_sprite;
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myWXPic = m_sprite;
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}
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public string path
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{
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get
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{
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//pc,ios //android :jar:file//
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return Application.persistentDataPath + "/ImageCache/";
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}
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}
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} |