Reflectionhelper not find

Hi I try to call some java method in OnAudioFilterRead function body.

Here is the code segment.

 void OnAudioFilterRead(float[] data, int channels)
    {
        AndroidJNI.AttachCurrentThread();

        if (ok)
        {
            if (obj == null)
            {
                obj = new AndroidJavaObject("com.xx.aop.media.av.GPUFrameCapturer");
                Debug.Log(obj.Call<bool>("isRecording"));

            }
        }
    }

When I build apk on android platform.

Always encountered this issure.

06-13 15:20:51.981 20255-20388/com.MeiTu.XRay E/Unity: AndroidJavaException: java.lang.ClassNotFoundException: Didn't find class "com.unity3d.player.ReflectionHelper" on path: DexPathList[[directory "."],nativeLibraryDirectories=[/system/lib, /vendor/lib, /system/lib, /vendor/lib]]
    java.lang.ClassNotFoundException: Didn't find class "com.unity3d.player.ReflectionHelper" on path: DexPathList[[directory "."],nativeLibraryDirectories=[/system/lib, /vendor/lib, /system/lib, /vendor/lib]]

Please help me .thanks.

OK, I solved this problem by myself.

The key stuff is …The first AndroidJavaObject or related things must be call at unity main thread.

the main thread own the related AndroidJNI or helper something like that class.

On the other side.

When you try to call AndroidJavaObject on other threads. Must be called AttachThread before.

That is all.