🎈 简介
本篇内容以 Unity 的一个相对较低的版本(2017.4.40)和一个相对较高的版本(2020.3.33)，来验证在低版本中是否可以使用高版本中构建的内容，包括如下内容：
🎈 低版本是否可以引用高版本构建的 dll
在 Unity2020.3.33 中，我们开启一个携程，使用UnityWebRequest发起网络请求来获取百度知道网页(www.baidu.com)上的内容，代码示例如下：
using UnityEngine;using System.Collections;using UnityEngine.Networking;
namespace SKFramework.Test{ public class TEST : MonoBehaviour { private void Start() { StartCoroutine(TestCoroutine()); }
private IEnumerator TestCoroutine() { string url = "www.baidu.com"; using (UnityWebRequest request = UnityWebRequest.Get(url)) { yield return request.SendWebRequest(); Debug.Log(request.downloadHandler.text); } } }}
复制代码
运行结果如下：
Console Log
其中 using 语句在C# 8.0中有了新的写法(C# 8.0中的新增功能 - C#指南)，如下图所示：
using 声明
我们在示例代码使用新的using声明：
using UnityEngine;using System.Collections;using UnityEngine.Networking;
namespace SKFramework.Test{ public class TEST : MonoBehaviour { private void Start() { StartCoroutine(TestCoroutine()); }
private IEnumerator TestCoroutine() { string url = "www.baidu.com"; using UnityWebRequest request = UnityWebRequest.Get(url); yield return request.SendWebRequest(); Debug.Log(request.downloadHandler.text); } }}
复制代码
在yield return request.SendWebRequest发起网络请求后，一般会先判断请求是否成功，在以往的 API 中会通过如下方式判断：
using UnityEngine;using System.Collections;using UnityEngine.Networking;
namespace SKFramework.Test{ public class TEST : MonoBehaviour { private void Start() { StartCoroutine(TestCoroutine()); }
private IEnumerator TestCoroutine() { string url = "www.baidu.com"; using UnityWebRequest request = UnityWebRequest.Get(url); yield return request.SendWebRequest(); if (request.isNetworkError || request.isHttpError) { Debug.Log(request.downloadHandler.text); } else { Debug.LogError(string.Format("发起网络请求失败：{0}", request.error)); } } }}
复制代码
但是当我们查看其定义可以发现它已经弃用(Obsolete)了：
//// 摘要:// Returns true after this UnityWebRequest encounters a system error. (Read Only)[Obsolete("UnityWebRequest.isNetworkError is deprecated. Use (UnityWebRequest.result == UnityWebRequest.Result.ConnectionError) instead.", false)]public bool isNetworkError => result == Result.ConnectionError;
//// 摘要:// Returns true after this UnityWebRequest receives an HTTP response code indicating// an error. (Read Only)[Obsolete("UnityWebRequest.isHttpError is deprecated. Use (UnityWebRequest.result == UnityWebRequest.Result.ProtocolError) instead.", false)]public bool isHttpError => result == Result.ProtocolError;
复制代码
因为在新版本使用新增属性result来判断请求是否成功：
using UnityEngine;using System.Collections;using UnityEngine.Networking;
namespace SKFramework.Test{ public class TEST : MonoBehaviour { private void Start() { StartCoroutine(TestCoroutine()); }
private IEnumerator TestCoroutine() { string url = "www.baidu.com"; using UnityWebRequest request = UnityWebRequest.Get(url); yield return request.SendWebRequest(); if (request.result == UnityWebRequest.Result.Success) { Debug.Log(request.downloadHandler.text); } else { Debug.LogError(string.Format("发起网络请求失败：{0}", request.error)); } } }}
复制代码
下面我们将其封装为一个接口并构建 dll 导入到 Unity2017.4.40 中去使用，接口代码如下：
using UnityEngine;using System.Collections;using UnityEngine.Networking;
namespace SKFramework.Test{ public class TEST { public void Execute(MonoBehaviour executer) { executer.StartCoroutine(TestCoroutine()); }
private IEnumerator TestCoroutine() { string url = "www.baidu.com"; using UnityWebRequest request = UnityWebRequest.Get(url); yield return request.SendWebRequest(); if (request.result == UnityWebRequest.Result.Success) { Debug.Log(request.downloadHandler.text); } else { Debug.LogError(string.Format("发起网络请求失败：{0}", request.error)); } } }}
复制代码
📍 如何构建 dll 动态库
打开Visual Studio创建新项目，模板选择如图所示：
创建新项目
C# 8.0对应框架.Net Framework 4.8(C#版本 与 .NET Framework 对应关系及各版本语法差异)
配置新项目
创建后将我们的示例代码拷入其中，发现 UnityEngine 的部分报错，因为我们还没有引用UnityEngine.dll
封装接口
UnityEngine.dll所在文件夹目录如下，需要到 Unity Editor 的安装目录下去找：
UnityEngine.dll
添加引用：
添加引用
引用添加完成，再次右键项目，点击生成，然后将生成的 dll 动态库导入到 Unity2017.4.40 创建的项目中。
生成dll动态库
📍 如何将 Unity 使用的 C#语言版本改为 6.0
参考文章：配置Unity2017和VS2015使用C# 6.0
在Player Sttings中将Scripting Runtime Version修改为Experimental(.Net 4.6 Equivalent)；
Player Settings
在Visual Studio中打开工具 - 选项 - 适用于 Unity 的工具 - 杂项，将访问项目属性修改为 true；
访问项目属性
重启再打开属性设置目标框架为.Net Framework 4.6.1，编写测试脚本：
using UnityEngine;using SKFramework.Test;
public class Example : MonoBehaviour { private void Start() { new TEST().Execute(this); }}
复制代码
运行结果：
运行结果
🎈 低版本是否可以加载高版本构建的 AssetsBundle
Prefab
Assets Bundle
#if UNITY_EDITORusing System.IO;using UnityEditor;using UnityEngine;
namespace SK.Framework.Tools{public class SimpleAssetsBundle : EditorWindow{ [MenuItem("SKFramework/Tools/Simple AssetsBundle")] public static void Open() { var window = GetWindow<SimpleAssetsBundle>(); window.titleContent = new GUIContent("Simple AssetsBundle"); window.minSize = new Vector2(300f, 100f); window.maxSize = new Vector2(1080f, 100f); window.Show(); }
//打包路径 private string path; //打包选项 private BuildAssetBundleOptions options; //目标平台 private BuildTarget target;
private const float labelWidth = 80f;
private void OnEnable() { path = EditorPrefs.HasKey(EditorPrefsKeys.path) ? EditorPrefs.GetString(EditorPrefsKeys.path) : Application.streamingAssetsPath; options = EditorPrefs.HasKey(EditorPrefsKeys.options) ? (BuildAssetBundleOptions)EditorPrefs.GetInt(EditorPrefsKeys.options) : BuildAssetBundleOptions.None; target = EditorPrefs.HasKey(EditorPrefsKeys.target) ? (BuildTarget)EditorPrefs.GetInt(EditorPrefsKeys.target) : BuildTarget.StandaloneWindows; }
private void OnGUI() { //路径 GUILayout.BeginHorizontal(); GUILayout.Label("Path", GUILayout.Width(labelWidth)); string newPath = EditorGUILayout.TextField(path); if (newPath != path) { path = newPath; EditorPrefs.SetString(EditorPrefsKeys.path, path); } //浏览 选择路径 if (GUILayout.Button("Browse", GUILayout.Width(60f))) { newPath = EditorUtility.OpenFolderPanel("AssetsBundle构建路径", Application.dataPath, string.Empty); if (!string.IsNullOrEmpty(newPath) && newPath != path) { path = newPath; EditorPrefs.SetString(EditorPrefsKeys.path, path); } } GUILayout.EndHorizontal();
//选项 GUILayout.BeginHorizontal(); GUILayout.Label("Options", GUILayout.Width(labelWidth)); var newOptions = (BuildAssetBundleOptions)EditorGUILayout.EnumPopup(options); if (newOptions != options) { options = newOptions; EditorPrefs.SetInt(EditorPrefsKeys.options, (int)options); } GUILayout.EndHorizontal();
//平台 GUILayout.BeginHorizontal(); GUILayout.Label("Target", GUILayout.Width(labelWidth)); var newTarget = (BuildTarget)EditorGUILayout.EnumPopup(target); if (newTarget != target) { target = newTarget; EditorPrefs.SetInt(EditorPrefsKeys.target, (int)target); } GUILayout.EndHorizontal();
GUILayout.FlexibleSpace();
//构建按钮 if (GUILayout.Button("Build")) { //检查路径是否有效 if (!Directory.Exists(path)) { Debug.LogError(string.Format("无效路径 {0}", path)); return; } //提醒 if (EditorUtility.DisplayDialog("提醒", "构建AssetsBundle将花费一定时间，是否确定开始？", "确定", "取消")) { //开始构建 BuildPipeline.BuildAssetBundles(path, options, target); } } }
private class EditorPrefsKeys { public static string path = "SIMPLEASSETSBUNDLE_PATH"; public static string options = "SIMPLEASSETSBUNDLE_OPTIONS"; public static string target = "SIMPLEASSETSBUNDLE_TARGET"; }}}#endif
复制代码
编写测试脚本：
using UnityEngine;using SKFramework.Test;using System.Collections;using UnityEngine.Networking;
public class Example : MonoBehaviour { private void Start() { //new TEST().Execute(this); StartCoroutine(ExampleCoroutine()); }
private IEnumerator ExampleCoroutine() { string url = Application.streamingAssetsPath + "/player";
WWW www = new WWW(url); yield return www; if (www.error == null) { var ab = www.assetBundle; Debug.Log(ab == null); } else { Debug.LogError(www.error); } }}
复制代码
运行结果：
Console Log
🎈 结论
以上述的结果来看，在相对较低的版本中，无论是引入相对较高的版本生成的 dll，还是加载相对较高版本构建的 ab 包，都会出现些许问题，是否有相应解决方案尚需确定。
Streaming Assets
评论