UnityCommon/base/ImageLoader.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using System.Threading.Tasks;
using System;


public class ImageLoader : MonoBehaviour
{
    // <20><><EFBFBD><EFBFBD><EFBFBD>ֵ<EFBFBD>
    private Dictionary<string, Sprite> imageCache = new Dictionary<string, Sprite>();
    public Sprite sprite;
    // <20>첽<EFBFBD><ECB2BD><EFBFBD><EFBFBD>ͼƬ
    public async Task<Sprite> LoadImageAsync(string url)
    {
        if (!IsValidUrl(url))
        {
            return sprite;
        }
        // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ѿ<EFBFBD><D1BE><EFBFBD>ͼƬ<CDBC><C6AC><EFBFBD><EFBFBD>ֱ<EFBFBD>ӷ<EFBFBD><D3B7>ػ<EFBFBD><D8BB><EFBFBD><EFBFBD><EFBFBD>ͼƬ
        if (imageCache.ContainsKey(url))
        {
            return imageCache[url];
        }

        // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>û<EFBFBD><C3BB>ͼƬ<CDBC><C6AC><EFBFBD><EFBFBD><EFBFBD>첽<EFBFBD><ECB2BD><EFBFBD><EFBFBD>
        using (UnityWebRequest webRequest = UnityWebRequestTexture.GetTexture(url))
        {
            // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>󲢵ȴ<F3B2A2B5><C8B4><EFBFBD>Ӧ
            var operation = webRequest.SendWebRequest();
            while (!operation.isDone)
                await Task.Yield(); // <20>ȴ<EFBFBD><C8B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɣ<EFBFBD>ʹ<EFBFBD><CAB9>await<69>Է<EFBFBD><D4B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ķ<EFBFBD>ʽ<EFBFBD><CABD><EFBFBD><EFBFBD>
            // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƿ<EFBFBD><C7B7>ɹ<EFBFBD>
            if (webRequest.result == UnityWebRequest.Result.Success)
            {
                // <20><>ȡ<EFBFBD><C8A1><EFBFBD>ص<EFBFBD><D8B5><EFBFBD><EFBFBD><EFBFBD>
                Texture2D texture = ((DownloadHandlerTexture)webRequest.downloadHandler).texture;

                // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
                imageCache[url] = TextureToSprite(texture);
                return imageCache[url];
            }
            else
            {
                //Debug.LogError("Failed to load image: " + webRequest.error);
                return sprite;
            }
        }
    }
    // <20><>Texture2Dת<44><D7AA>ΪSprite
    Sprite TextureToSprite(Texture2D texture)
    {
        // ʹ<><CAB9><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ijߴ紴<DFB4><E7B4B4>һ<EFBFBD><D2BB>Sprite
        return Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
    }

    public static bool IsValidUrl(string url)
    {
        Uri uriResult;
        return Uri.TryCreate(url, UriKind.Absolute, out uriResult) && (uriResult.Scheme == Uri.UriSchemeHttp || uriResult.Scheme == Uri.UriSchemeHttps);
    }
}