Unity与Android原生交互报错：java.lang.NoSuchFieldError求助

报错信息 #

2023/08/12 02:04:24.141 3621 3686 Error Unity AndroidJavaException: java.lang.NoSuchFieldError: no type "" found and so no field "currentActivity" could be found in class "Lcom/unity3d/player/UnityPlayer;" or its superclasses
2023/08/12 02:04:24.141 3621 3686 Error Unity java.lang.NoSuchFieldError: no type "" found and so no field "currentActivity" could be found in class "Lcom/unity3d/player/UnityPlayer;" or its superclasses
2023/08/12 02:04:24.141 3621 3686 Error Unity     at com.unity3d.player.UnityPlayer.nativeRender(Native Method)
2023/08/12 02:04:24.141 3621 3686 Error Unity     at com.unity3d.player.UnityPlayer.-$$Nest$mnativeRender(Unknown Source:0)
2023/08/12 02:04:24.141 3621 3686 Error Unity     at com.unity3d.player.UnityPlayer$C$a.handleMessage(Unknown Source:122)
2023/08/12 02:04:24.141 3621 3686 Error Unity     at android.os.Handler.dispatchMessage(Handler.java:103)
2023/08/12 02:04:24.141 3621 3686 Error Unity     at android.os.Looper.loop(Looper.java:214)
2023/08/12 02:04:24.141 3621 3686 Error Unity     at com.unity3d.player.UnityPlayer$C.run(Unknown Source:24)
2023/08/12 02:04:24.141 3621 3686 Error Unity   at UnityEngine.AndroidJNISafe.CheckException () [0x0008d] in /home/bokken/build/output/unity/unity/Modules/AndroidJNI/AndroidJNISafe.cs:24
2023/08/12 02:04:24.141 3621 3686 Error Unity   at UnityEngine.AndroidJNISafe.GetStaticFieldID (System.IntPtr clazz, System.String name, System.String sig) [0x0000e] in /home/bokken/build/output/unity/unity/Modules/An

触发场景 #

执行以下代码时触发报错：

AndroidJavaClass unityPlayerClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer");

或

Permission.HasUserAuthorizedPermission(PERMISSION_BLUETOOTH)

当前Manifest配置 #

<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.unity3d.player"
    xmlns:tools="http://schemas.android.com/tools">
    <application>
        <activity android:name="com.unity3d.player.UnityPlayerActivity"
                  android:theme="@style/UnityThemeSelector"
                  android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <meta-data android:name="unityplayer.UnityActivity" android:value="true" />
        </activity>
    </application>
</manifest>

排查与解决步骤 #

• 检查Unity Android模块完整性：打开Unity Hub，找到当前使用的Unity版本，查看Android Build Support下的组件（Android SDK & NDK Tools、OpenJDK）是否完整，若有缺失，点击"添加组件"修复安装。
• 清理项目缓存：删除项目根目录的Library、Temp、Obj文件夹；打开Build Settings点击Clean Build清理安卓构建缓存，之后重启Unity重新构建。
• 排查AAR包冲突：临时移除项目中所有第三方AAR包，测试安卓交互是否恢复正常。如果正常，逐个重新引入AAR，找出冲突的包并替换为兼容当前Unity版本的版本（冲突通常来自AAR包含了旧版UnityPlayer类）。
• 验证代码调用规范：确保安卓交互代码在Unity主线程执行，获取currentActivity的标准写法如下：

  AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
  AndroidJavaObject currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
  

• 检查构建混淆配置：若开启了R8/ProGuard，确保ProGuard规则中保留了Unity相关类：

  -keep class com.unity3d.player.** { *; }
  -keep class com.unity3d.** { *; }
  

  检查自定义ProGuard文件是否包含上述规则，若没有则添加。
• 回退版本验证：通过Git切换到之前能正常运行的提交版本，测试安卓交互功能。若正常，逐步合并UI开发代码，定位导致问题的具体变更。

内容的提问来源于stack exchange，提问作者Santiago14