1、新建一個Android Studio工程，選擇空Activity

2、創建一個Module

3、將Unity的依賴jar包拷貝到工程的libs下

4、增加Java代碼

內容修改如下

package com.example.mylibrary;

/**
 * Created by Bruce on 2017/7/11.
 */

import com.unity3d.player.UnityPlayerActivity;
import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends UnityPlayerActivity {
    @Override
    
 
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);

    }
}

5、修改mylibary的gradle，增加

task makeJar(type: Copy) {
    //刪除存在的
    delete ‘build/libs/mylibrary.jar‘
    //設置拷貝的文件
    from(‘build/intermediates/bundles/debug/‘)
    //打進jar包後的文件目錄
    into(‘build/libs/‘)
    //將classes.jar放入build/libs/目錄下
    //include ,exclude參數來設置過濾
    //（我們只關心classes.jar這個文件）
    include(‘classes.jar‘)
    //重命名
    rename (‘classes.jar‘, ‘mylibrary.jar‘)
}

makeJar.dependsOn(build)

6、修改app的gradle，增加

7、在Android Studio的命令行裏輸入gradlew makeJar

8、查看輸出

9把mysdk.jar拷貝到Unity工程

10、修改AndroidManifest文件啟動Activity為MainActivity

<activity android:label="@string/app_name" android:screenOrientation="fullSensor" android:launchMode="singleTask" android:configChanges="mcc|mnc|locale|touchscreen|keyboard|keyboardHidden|navigation|orientation|screenLayout|uiMode|screenSize|smallestScreenSize|fontScale
 
" android:name=".MainActivity">
      <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
        <category android:name="android.intent.category.LEANBACK_LAUNCHER" />
      </intent-filter>
      <meta-data android:name="unityplayer.UnityActivity" android:value="true" />
    </activity>

11、導出Apk

用Android Studio導出jar給Unity3D用