Unity：从Unity调用同伴对象内的Android Kotlin函数

Question

我是一个本地开发人员和新的Unity。我试图发挥我的优势，在Kotlin编码，然后使用我的代码作为一个插件在Unity。我遇到的一个问题是，我不知道如何引用伴生对象内部的函数。

class MyAnalytics internal constructor(
    private val MyAnalyticsConfiguration: MyAnalyticsConfiguration
) : MyAnalyticsLogger {

    .
    .
    .

    override fun logEvent(eventRequest: Event?) {
        // some code in here
    }

    companion object {

        @JvmStatic
        fun factory(
            context: Context,
            MyAnalyticsConfiguration: MyAnalyticsConfiguration = MyAnalyticsConfiguration()
        ) : MyAnalytics {
            val eventExecutor = MyWorkManager(
                workManager = WorkManager.getInstance(context.applicationContext),
                MyAnalyticsConfiguration = MyAnalyticsConfiguration
            )
            return MyAnalytics(
                MyAnalyticsConfiguration
            )
        }
    }
}

MyAnalytics.factory(
      context = requireActivity()
)

但我怎样才能在团结中也这样做呢？以下是我尝试过的。

AndroidJavaClass UnityPlayerClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
AndroidJavaObject UnityPlayerActivity = UnityPlayerClass.GetStatic<AndroidJavaObject>("currentActivity");
AndroidJavaObject myAnalytics = new AndroidJavaObject("com.test.analytics.MyAnalytics");
AndroidJavaObject analyticsObject = myAnalytics.Call<AndroidJavaObject>("factory", UnityPlayerActivity); //Also tried with 'CallStatic'; no result, same error

我收到的错误是，

AndroidJavaException：java.lang.NosuchMethodError：没有具有name='factory'signature='(landroid.app.application；）ljava/lang/object；‘在Ljava.lang.Object类中；12-10 14:00:21.883 135 37 136 74 E Unity：java.lang.nosuchmethoderror：没有具有name='factory'signature='(landroid.app.application；）ljava/lang/object；‘在Ljava.lang.Object类中；12-10 14:00:21.883 135 37 136 74 E Unity：at com.unity3d.player.reflectionhelper.getmethodid（未知来源：162）12-10 14:00:21.883 135 37 136 74 E Unity：at com.unity3d.player.unityplayer.nativerender（原生方法）12-10 14:00:21.883 135 37 136 74 E Unity：at com.unity3d.player.unityplayer.Access$300（未知来源：0）12-10 14:00:21.883 135 37 136 74 E Unity：at com.unity3d.player.UnityPlayer.Access$300（未知14:00:21.883 135 37 136 74 E Unity：at android.os.handler.dispatchmessage（handler.java:103)12-10 14:00:21.883 135 37 136 74 E Unity：at android.os.looper.loop（looper.java:214)12-10 14:00:21.883 135 37 136 74 E Unity：at com.unity3d.player.unityplayer$E.run（未知来源：20）

Answer 1

为了理解实现中的问题所在，实际上需要将Kotlin代码反编译为Java代码，并基于Java代码而不是Kotlin实现Unity部分。

让我们举一个Kotlin代码的简单示例，它将打印日志，仅此而已：

class MyKotlinClass(val name: String = "DEFAULT NAME") {
    fun callNormalFunc() {
        Log.d("UNITY", "callNormalFunc from Kotlin code")
    }
    companion object {
        @JvmStatic
        fun callStaticCompanionFunc(): MyKotlinClass {
            Log.d("UNITY", "callStaticCompanionFunc from Kotlin code")
            return MyKotlinClass("NEW NAME")
        }
    }
}

反编译的Java代码如下所示：

public final class MyKotlinClass {
   @NotNull
   private final String name;
   @NotNull
   public static final MyKotlinClass.Companion Companion = new MyKotlinClass.Companion((DefaultConstructorMarker)null);

   public final void callNormalFunc() {
      Log.d("UNITY", "callNormalFunc from Kotlin code");
   }

   @NotNull
   public final String getName() {
      return this.name;
   }

   public MyKotlinClass(@NotNull String name) {
      Intrinsics.checkNotNullParameter(name, "name");
      super();
      this.name = name;
   }

   // $FF: synthetic method
   public MyKotlinClass(String var1, int var2, DefaultConstructorMarker var3) {
      if ((var2 & 1) != 0) {
         var1 = "DEFAULT NAME";
      }

      this(var1);
   }

   public MyKotlinClass() {
      this((String)null, 1, (DefaultConstructorMarker)null);
   }

   @JvmStatic
   @NotNull
   public static final MyKotlinClass callStaticCompanionFunc() {
      return Companion.callStaticCompanionFunc();
   }

   public static final class Companion {
      @JvmStatic
      @NotNull
      public final MyKotlinClass callStaticCompanionFunc() {
         Log.d("UNITY", "callStaticCompanionFunc from Kotlin code");
         return new MyKotlinClass("NEW NAME");
      }

      private Companion() {
      }

      // $FF: synthetic method
      public Companion(DefaultConstructorMarker $constructor_marker) {
         this();
      }
   }
}

从反编译的代码中我们可以看到，实际上我们可以用两种方式调用标记为@jvmstatic的函数。首先直接从我们的对象，其次使用companion对象。

public class KotlinCallScript : MonoBehaviour {

    private AndroidJavaObject _object;
    private AndroidJavaClass _staticClass;
    // Start is called before the first frame update
    private void Start () {
        _object = new AndroidJavaObject ("com.hardartcore.kotlin.MyKotlinClass");
        _staticClass = new AndroidJavaClass ("com.hardartcore.kotlin.MyKotlinClass");
        var defaultName = _object.Call<string> ("getName");
        Debug.Log ("START GET DEFAUL NAME: " + defaultName);
    }

    public void CallNormalFunction () {
        _object.Call ("callNormalFunc");
    }

    public void CallStaticFunction () {
        var companionObject = _staticClass.GetStatic<AndroidJavaObject> ("Companion");
        var newName = companionObject.Call<AndroidJavaObject> ("callStaticCompanionFunc").Call<string> ("getName");
        Debug.Log ("CALL STATIC FUNCTION NEW NAME: " + newName);
    }

    public void CallSecondWay () {
        var kotlinObject = _object.CallStatic<AndroidJavaObject> ("callStaticCompanionFunc");
        var newName = kotlinObject.Call<string> ("getName");
        Debug.Log ("CALL SECOND WAY NEW NAME: " + newName);
    }

}

你会喜欢哪种方式由你决定。

我的建议是看看你的反编译Java代码，把它贴在这里，这样我们就可以理解为什么它不能工作。