1.so源文件

1.1 NaviteCode.h

    #ifndef __NativeCode_H__
    #define __NativeCode_H__

    #if 0
    #define EXPORT_DLL __declspec(dllexport) //导出dll声明
    #else
    #define EXPORT_DLL 
    #endif

    extern "C" {
        EXPORT_DLL int MyAddFunc(int _a, int _b);
		EXPORT_DLL char* GetAppKey();
    }

    #endif

1.2 NaviteCode.cpp

    #include "NaviteCode.h"
    #include <cstring>
    using namespace std;

    extern "C" {
        int MyAddFunc(int _a, int _b)
        {
            return _a + _b;
        }

        // static char* key = "aShLdS$u3p@V-btd5dKmQZdwa";
		
        char buff[255]; 
        char* GetAppKey()
        {
            strcpy(buff,"aShLdS$u3p@V-btd5dKmQZdwa");
            return buff;
		    //return "aShLdS$u3p@V-btd5dKmQZdwa";
        }

}

2.调用方法

将上述生成的so文件放在Plugins-Android下

using System;
using System.Runtime.InteropServices;

public class Jni
{
    [DllImport("NativeCode")]
    public static extern IntPtr GetAppKey();
}

public class Usage
{
    private string GetAppKey()
    {
        IntPtr keyPtr = Jni.GetAppKey();
        string appKey = Marshal.PtrToStringAnsi(keyPtr);
        Debug.Log("Login result:Get appKey " + appKey);

        return appKey;
    }
}