Unity2021版本UnityWebRequest使用方法参考

获取AssetBundle：

IEnumerator GetAssetBundle(string path, UnityAction<AssetBundle> onGetAssetBundle)
{
	using (UnityWebRequest webRequest = UnityWebRequestAssetBundle.GetAssetBundle(path))
	{
		yield return webRequest.SendWebRequest();
		if (webRequest.result == UnityWebRequest.Result.Success)
		{
			AssetBundle ab = (webRequest.downloadHandler as DownloadHandlerAssetBundle).assetBundle;
			onGetAssetBundle?.Invoke(ab);
		}
		else
		{
			Debug.Log("error = " + webRequest.error + "\n Load Path = " + path);
			onGetAssetBundle?.Invoke(null);
		}
	}
}

获取文本：

IEnumerator GetText(string path, UnityAction<string> onGetJson)
{
	using (UnityWebRequest webRequest = UnityWebRequest.Get(path))
	{
		yield return webRequest.SendWebRequest();

		if (webRequest.result == UnityWebRequest.Result.Success)
		{
			string json = webRequest.downloadHandler.text;
			onGetJson?.Invoke(json);
		}
		else
		{
			Debug.Log("error = " + webRequest.error + "\n Load Path = " + path);
			onGetJson?.Invoke(null);
		}
	}
}

获取图片：

IEnumerator GetTexture2D(string path, UnityAction<Texture2D> onGetTexture2D)
{
	using (UnityWebRequest webRequest = UnityWebRequestTexture.GetTexture(path))
	{
		yield return webRequest.SendWebRequest();
		if (webRequest.result == UnityWebRequest.Result.Success)
		{
			Texture2D tex2d = DownloadHandlerTexture.GetContent(webRequest);
			onGetTexture2D?.Invoke(tex2d);
		}
		else
		{
			Debug.Log("error = " + webRequest.error + "\n Load Path = " + path);
			onGetTexture2D?.Invoke(null);
		}
	}
}

获取音频：

IEnumerator GetAudio(string path, AudioType type, UnityAction<AudioClip> onGetAudio)
{
	using (UnityWebRequest webRequest = UnityWebRequestMultimedia.GetAudioClip(path, type))
	{
		yield return webRequest.SendWebRequest();

		if (webRequest.result == UnityWebRequest.Result.Success)
		{
			AudioClip clip = DownloadHandlerAudioClip.GetContent(webRequest);
			onGetAudio?.Invoke(clip);
		}
		else
		{
			Debug.Log("error = " + webRequest.error + "\n Load Path = " + path);
			onGetAudio?.Invoke(null);
		}
	}
}

加载视频：

这个事情早期版本要用到MovieTexure之类的，Unity2021版本加载视频实际上和UnityWebRequest没有毛线关系，请使用VideoPlayer，哈哈。

附一个Result枚举的介绍：

Result值	内容描述
InProgress	请求尚未完成。
Success	请求成功。
ConnectionError	无法与服务器进行通信。例如，请求无法连接或无法建立安全通道。
ProtocolError	服务器返回了一个错误响应。请求成功与服务器通信，但收到连接协议定义的错误。
DataProcessingError	处理数据时出错。请求成功与服务器通信，但在处理接收到的数据时遇到错误。例如，数据损坏或格式不正确。

另附AssetBundle创建参考脚本（这个脚本注意放到Editor文件夹下）：

using System.IO;
using UnityEditor;
using UnityEngine;

public class BuildAssetBundle : MonoBehaviour
{
	static void Package(BuildTarget buildTarget)
	{
		string packagePath = EditorUtility.OpenFolderPanel("Set " + buildTarget + " Save Path", Application.dataPath, "");
		if (packagePath.Length <= 0 || !Directory.Exists(packagePath))
		{
			Debug.Log("Directory Error!");
			return;
		}
		BuildPipeline.BuildAssetBundles(packagePath, BuildAssetBundleOptions.None, buildTarget);
		AssetDatabase.Refresh();
	}

	[MenuItem("BuildAssetBundle / WebGL")]
	static void PackageWebGL()
	{
		Package(BuildTarget.WebGL);
	}

	[MenuItem("BuildAssetBundle / Window")]
	static void PackageWindow()
	{
		Package(BuildTarget.StandaloneWindows);
	}

	[MenuItem("BuildAssetBundle / Android")]
	static void PackageAndroid()
	{
		Package(BuildTarget.Android);
	}
}