unity3d：url下载头像保存在本地（微信头像）

水深无声 2022-04-10 05:17 478阅读 0赞

using UnityEngine;
    using UnityEngine.UI;
    using System.Collections;
    using System.IO;
    using System.Collections.Generic;
    
    public class AsyncImageDownload : MonoBehaviour
    {
        Dictionary<int, Sprite> m_dicHeadSpr = new Dictionary<int, Sprite>();
    
        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/");
            }
            
            return true;
        }
    
        public void StartUp()
        {
    
        }
    
        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
            int code = url.GetHashCode();
            if (m_dicHeadSpr.ContainsKey(code))
            {
                image.sprite = m_dicHeadSpr[code];
            }
            else       //如果之前不存在缓存中  就用WWW类下载
            {
                //判断是否是第一次加载这张图片
                if (!File.Exists(path + code.ToString() + ".txt"))
                {
                    //如果之前不存在缓存文件
                    StartCoroutine(DownloadImage(url, image,code));
                }
                else
                {
                    StartCoroutine(LoadLocalImage(url, image,code));
                }
            }
        }
    
        IEnumerator DownloadImage(string url, Image image, int code)
        {
            WWW www = new WWW(url);
            yield return www;
    
            Texture2D tex2d = www.texture;
    
    
    
            Sprite sprite = Sprite.Create(tex2d, new Rect(0, 0, tex2d.width, tex2d.height), new Vector2(0, 0));
            image.sprite = sprite;
    
            byte[] pngData = tex2d.EncodeToPNG();
            File.WriteAllBytes(path + code.ToString() + ".txt", pngData);
    
            m_dicHeadSpr[code] = sprite;
        }
    
        IEnumerator LoadLocalImage(string url, Image image,int code)
        {
            string filePath = "file:///" + path + code.ToString() + ".txt";
            //     Debug.Log("getting local image:" + filePath);
            WWW www = new WWW(filePath);
            yield return www;
    
            Texture2D texture = www.texture;
            Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0, 0));
            image.sprite = sprite;
            m_dicHeadSpr[code] = sprite;
    
        }
    
        public string path
        {
            get
            {
                //pc,ios //android :jar:file//
                return Application.persistentDataPath + "/ImageCache/";
    
            }
        }
    }