Unity 加载图片的两种方式文件流和UnityWebRequest

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

public class DemoTest : MonoBehaviour
{
    string url = @"E:/simulator/Assets/Images/details/btn_go.png";
    [SerializeField] private Image im;
    // Start is called before the first frame update
    void Start()
    {
        // Texture2D t = new Texture2D(1,1);
        // t.LoadImage(ReadTexture(url));
        // Sprite spr = Sprite.Create(t, new Rect(0,0,t.width,t.height), new Vector2(10.0f,10.0f));
        // im.sprite = spr;

        StartCoroutine(LoadTexture(url));
    }

    // Update is called once per frame
    void Update()
    {
        
    }

    #region 方法一：通过文件流（System.IO）的形式加载
    /// <summary>
    /// 文件路径
    /// </summary>
    /// <param name="path"></param>
    /// <returns></returns>
    private byte[] ReadTexture(string path){
        FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read);

        fileStream.Seek(0, SeekOrigin.Begin);
        //创建文件长度buffer
        byte[] b = new byte[fileStream.Length];
        fileStream.Read(b,0,(int)fileStream.Length);
        fileStream.Close();
        fileStream.Dispose();
        fileStream = null;

        return b;
    }
    #endregion

    #region 方法二：通过UnityWebRequest加载
    IEnumerator LoadTexture(string url){
        var uri = new Uri(Path.Combine(url));
        UnityWebRequest uwr = UnityWebRequest.Get(uri);
        DownloadHandlerTexture tex = new DownloadHandlerTexture(true);
        uwr.downloadHandler = tex;

        yield return uwr.SendWebRequest();

        if(uwr.isHttpError || uwr.isNetworkError){
            Debug.LogError(uwr.error);
        }
        else{
            Texture2D t2d = new Texture2D(1,1);
            t2d = tex.texture;
            Sprite spr = Sprite.Create(t2d, new Rect(0,0,t2d.width,t2d.height), new Vector2(0.5f,0.5f));
            im.sprite = spr;
        }
    }
    #endregion
}