miduo_client/Assets/LuaFramework/Scripts/SetInternetPic/AsyncImageDownload.cs

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2020-05-09 13:31:21 +08:00
using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System.IO;
public class AsyncImageDownload : MonoBehaviour
{
public Sprite myWXPic;
private static AsyncImageDownload _instance = null;
public static AsyncImageDownload GetInstance()
{ return Instance; }
public static AsyncImageDownload Instance
{
get
{
if (_instance == null)
{
GameObject obj = new GameObject("AsyncImageDownload");
_instance = obj.AddComponent<AsyncImageDownload>();
DontDestroyOnLoad(obj);
_instance.Init();
}
return _instance;
}
}
public bool Init()
{
if (!Directory.Exists(Application.persistentDataPath + "/ImageCache/"))
{
Directory.CreateDirectory(Application.persistentDataPath + "/ImageCache/");
}
myWXPic = null;
return true;
}
public void SetAsyncImage(string url, Image image)
{
//开始下载图片前将UITexture的主图片设置为占位图
if (myWXPic != null)
{
image.sprite = myWXPic;
return;
}
//判断是否是第一次加载这张图片
if (!File.Exists(path + url.GetHashCode()))
{
//如果之前不存在缓存文件
StartCoroutine(DownloadImage(url, image));
}
else
{
StartCoroutine(LoadLocalImage(url, image));
}
}
IEnumerator DownloadImage(string url, Image image)
{
Debug.Log("downloading new image:" + path + url.GetHashCode());//url转换HD5作为名字
WWW www = new WWW(url);
yield return www;
Texture2D tex2d = www.texture;
//将图片保存至缓存路径
byte[] pngData = tex2d.EncodeToPNG(); //将材质压缩成byte流
File.WriteAllBytes(path + url.GetHashCode(), pngData); //然后保存到本地
Sprite m_sprite = Sprite.Create(tex2d, new Rect(0, 0, tex2d.width, tex2d.height), new Vector2(0, 0));
image.sprite = m_sprite;
myWXPic = m_sprite;
}
IEnumerator LoadLocalImage(string url, Image image)
{
string filePath = "file:///" + path + url.GetHashCode();
WWW www = new WWW(filePath);
yield return www;
Texture2D texture = www.texture;
Sprite m_sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0, 0));
image.sprite = m_sprite;
myWXPic = m_sprite;
}
public string path
{
get
{
//pc,ios //android :jar:file//
return Application.persistentDataPath + "/ImageCache/";
}
}
}