unity+ndk+android+.so+apk

系统环境：win10 + Unity 2018.3.13f1 (64-bit)

1. 安装NDK

解压下载后的文件夹，将文件夹路径添加到系统环境变量Path中

2. 编写文件

makeSo文件夹名称可以修改，但jni不要修改

参考链接：https://docs.unity3d.com/Manual/PluginInspector.html

Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)

LOCAL_MODULE     :=  NativeCode
LOCAL_C_INCLUDES := $(LOCAL_PATH)
LOCAL_SRC_FILES  := NaviteCode.cpp
LOCAL_LDLIBS     := -llog -landroid
LOCAL_CFLAGS    := -DANDROID_NDK

include $(BUILD_SHARED_LIBRARY)

Application.mk

APP_STL := c++_static
APP_CPPFLAGS := -frtti -std=c++11
APP_PLATFORM := android-19
APP_CFLAGS += -Wno-error=format-security
APP_BUILD_SCRIPT := Android.mk
APP_ABI := armeabi-v7a x86

NaviteCode.cpp

#include "NaviteCode.h"

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

NaviteCode.h

#ifndef __NativeCode_H__
#define __NativeCode_H__

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

#endif

3. ndk-build

Win+r：输入cmd

会生成obj libs两个文件夹

4. 新建unity工程

将libs文件夹复制到Assets/Plugins/Android，没有则自己创建

show.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Runtime.InteropServices;

public class show : MonoBehaviour
{
    [DllImport("NativeCode")]
    public static extern int MyAddFunc(int x, int y);

    // Start is called before the first frame update
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {
        gameObject.transform.Translate(new Vector3(0, 0, MyAddFunc(1, 1)));
    }
}

将show.cs绑定到一个物体中，实现运动功能

5.生成apk

file->Build Settings

6.注意事项

不论怎么选择，editor中是无法运行程序的，会一直报错dllnotfoundexception，发布成apk在安卓真机或模拟器上运行即可