First, talk about my work environment, they are Qt 5.11, NDK-r10e, and sdk-tools-windows-4333796. And then based on this environment, I make a demo to verify the idea of  use JNI method to link Java and C++ method. When I finish the code, compile it, that is no error. But build it on the phone, there is one mistake. It is like this:

java.lang.UnsatisfiedLinkError: No implementation found for void org.qtproject.example.DataNatives(int, int)....

I read the issue https://bugreports.qt.io/browse/QTBUG-68488, but I don't know where I should add the "System.loadLibrary("TestAndroid_5_11")".  (libTestAndroid_5_11  is the *so file name of my program.).

Here is how I do that: 

• First, I use JNI_OnLoad method to register the native method, like this:

    jint JNI_OnLoad(JavaVM* vm, void* reserved)
    {
        Q_UNUSED(reserved);
        JNIEnv* env;
        if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK)
        {
            return -1;
        }
        JNINativeMethod javaMethods[]{
            {"nativeSendData", "(II)V", reinterpret_cast<void*>(jniSendData)}
        };
    
        QAndroidJniEnvironment jniEnv;
        if (jniEnv->ExceptionCheck())
        {
            jniEnv->ExceptionDescribe();
            jniEnv->ExceptionClear();
        }
    
        jclass objectClass = jniEnv->FindClass("qtTest/DataNatives");
        if(!objectClass)
        {
            qWarning() << "setNativeMethods....Couldn't find class:" << kJniClassName;
            return;
        }
    
        jint val = jniEnv->RegisterNatives(objectClass, javaMethods, sizeof(javaMethods) / sizeof(javaMethods[0]));
    
        if (val < 0)
        {
            qWarning() << ":setNativeMethods....Error registering methods: " << val;
        }
        else
        {
            qDebug() << "setNativeMethods....Native Functions Registered";
        }
    
        if (jniEnv->ExceptionCheck())
        {
            jniEnv->ExceptionDescribe();
            jniEnv->ExceptionClear();
        }

        return JNI_VERSION_1_6;
    }

• then, I make the java method ,like this:

  package qtTest;
  
  import android.os.Bundle;
  import android.util.Log;
  
  import org.qtproject.qt5.android.bindings.QtActivity;
  
  class DataNatives
  {
      public static native void nativeSendData(int val1, int val2);
  }
  
  public class TestActivity extends QtActivity
  {
      @Override
      protected void onResume()
      {
          super.onResume();
  
          Log.i("TestActivity","onResume");
          DataNatives.nativeSendData(1, 2);
      }
  
  
      @Override
      public void onWindowFocusChanged(boolean hasFocus)
      {
          Log.i("TestActivity","onWindowFocusChanged");
          DataNatives.nativeSendData(3, 4);
          super.onWindowFocusChanged(hasFocus);
      }
  }
  

• Last, I make the C++ method, like this:

  static void jniSendData(JNIEnv *envA, jobject thizA, jint val1, jint val2)
  {
      Q_UNUSED(thizA);
      if (val1 != 0)
      {
          qDebug()<<"jniSendData----val1="<<val<<",val2="<<val2;
          envA->ReleaseByteArrayElements(val1, val2, JNI_ABORT);
      }
  }

  So how can I solve this problem?