WEP_V2.1.3/SourceCode/WeApp.3D.Test/WeApp.3D/Assets/Plugins/CommonTool/AsyncImageDownload.cs

using System.Collections;
using System.IO;
using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.UI;

namespace Assets.Plugins.CommonTool
{
    public class AsyncImageDownload : MonoBehaviour
    {

        public Sprite placeholder;

        private static AsyncImageDownload _instance;
        //public static AsyncImageDownload GetInstance() { return Instance; }
        public static AsyncImageDownload Instance
        {
            get
            {
                if (_instance == null)
                {
                    GameObject obj = new GameObject("AsyncImageDownloadObj");
                    _instance = obj.AddComponent<AsyncImageDownload>();
                    DontDestroyOnLoad(obj);
                    _instance.Init();
                }
                return _instance;
            }
        }


        public bool Init()
        {
            if (!Directory.Exists(Application.persistentDataPath + "/ImageCache/"))
            {
                Directory.CreateDirectory(Application.persistentDataPath + "/ImageCache/");
            }
            if (placeholder == null)
            {
                placeholder = Resources.Load("placeholder") as Sprite;
            }
            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
            image.sprite = placeholder;
            //判断是否是第一次加载这张图片
            //StartCoroutine(!File.Exists(path + url.GetHashCode()) ? DownloadImage(url, image) : LoadLocalImage(url, image));
            StartCoroutine(DownloadImage(url, image));
        }

        public void SetAsyncImage(string url,GameObject go)
        {
            StartCoroutine(LoadTextureFromInternet(url, go));
        }


        //IEnumerator DownloadImage(string url, Image image)

        //{
        //    Debug.Log("downloading new image:" + path + url.GetHashCode());//url转换HD5作为名字
        //    var 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();
        //    File.WriteAllBytes(path + url.GetHashCode(), pngData);
        //    Sprite m_sprite = Sprite.Create(tex2d, new Rect(0, 0, tex2d.width, tex2d.height), new Vector2(0, 0));
        //    image.sprite = m_sprite;

        //}
        IEnumerator DownloadImage( string url,Image imageComp)
        {
            //using UnityWebRequest uwr = UnityWebRequestTexture.GetTexture(url);
            //yield return uwr.SendWebRequest();
            //if (uwr.result ==UnityWebRequest.Result.ProtocolError) 
            //    Debug.Log(uwr.error);
            //else
            //{
            //    if (uwr.isDone)
            //    {

            //        //Texture2D texture2d = new Texture2D(width, height);
            //        var texture2d = DownloadHandlerTexture.GetContent(uwr);
            //        int width = texture2d.width; //1920;
            //        int height = texture2d.height; //1080;
            //        byte[] pngData = texture2d.EncodeToPNG();
            //        File.WriteAllBytes(path + url.GetHashCode(), pngData);
            //        Sprite tempSprite = Sprite.Create(texture2d, new Rect(0, 0, width, height), new Vector2(0.5f, 0.5f));
            //        imageComp.sprite = tempSprite;
            //        Resources.UnloadUnusedAssets();
            //    }
            //}
            UnityWebRequest request = new UnityWebRequest(url);
            DownloadHandlerTexture texture = new DownloadHandlerTexture(true);
            request.downloadHandler = texture;
            yield return request.SendWebRequest();
            if (request.result == UnityWebRequest.Result.ProtocolError)
            {
                Debug.Log(request.error);
            }
            var pic = texture.texture;
            Sprite sp = Sprite.Create((Texture2D)pic, new Rect(0, 0, pic.width, pic.height), Vector2.zero);
            imageComp.sprite = sp;

        }
      


        IEnumerator LoadLocalImage(string url, Image imageComp)
        {
            string filePath = "file:///" + path + url.GetHashCode();
            Debug.Log("getting local image:" + filePath);
            using UnityWebRequest uwr = UnityWebRequestTexture.GetTexture(url);
            yield return uwr.SendWebRequest();
            //WWW www = new WWW(filePath);
            //yield return www;
            if (uwr.result == UnityWebRequest.Result.ProtocolError)
                Debug.Log(uwr.error);
            else
            {
                if (uwr.isDone)
                {
                    //Texture2D texture2d = new Texture2D(width, height);
                    var texture2d = DownloadHandlerTexture.GetContent(uwr);
                    int width = texture2d.width; //1920;
                    int height = texture2d.height; //1080;
                    Sprite tempSprite = Sprite.Create(texture2d, new Rect(0, 0, width, height), new Vector2(0.5f, 0.5f));
                    imageComp.sprite = tempSprite;
                    Resources.UnloadUnusedAssets();
                }
            }
        }
        IEnumerator LoadTextureFromInternet(string url,GameObject go)
        {
            UnityWebRequest request = new UnityWebRequest(url);
            DownloadHandlerTexture texture = new DownloadHandlerTexture(true);
            request.downloadHandler = texture;
            yield return request.SendWebRequest();
            if (request.result == UnityWebRequest.Result.ProtocolError)
            {
                Debug.Log(request.error);
            }
            var pic = texture.texture;
            Image tempImage = go.GetComponent<Image>();
            if (tempImage != null)
            {
                Sprite sp = Sprite.Create((Texture2D)pic, new Rect(0, 0, pic.width, pic.height), Vector2.zero);
                tempImage.sprite = sp;
                go.GetComponent<MeshRenderer>().material.mainTexture = pic;
            }
            else
            {
                Debug.Log("物体上添加【IMAGE】组件");

            }

        }
       

        public string path => Application.persistentDataPath + "/ImageCache/"; //pc,ios //android :jar:file//
    }
}