Unity-Android-Plugin

开发环境Windows平台（Unity2017.1.0f3 Personal ，Android Studio 2.3.3）

在Unity项目中构建和使用Android Plugin

Unity支持几种类型的Android plug-ins：

1. AAR 插件 和 Android Library
2. JAR 插件
3. 继承UnityPlayerActivity
4. Native(C++) 插件

Unity Android runtime

Untiy Android runtime通过继承自FrameLayout的UnityPlayer实现，UnityPlayer实现了触控，键盘输入，相机，位置等特性。虽然这个UnityPlayer实现了大部分的native功能，但它不是应用程序的入口。

在通用的Android Unity应用程序中，程序的入口是UnityPlayerActivity。如果你看一下APK文件反编译后的AndroidManifest.xml文件，可以看到它是如何标记UnityPlayerActivity作为应用程序的Launcher的。

查看Unity安装目录发现，UnityPlayerActivity的源码可以在C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer\Source中查看。

public class UnityPlayerActivity extends Activity
{
    protected UnityPlayer mUnityPlayer; // don't change the name of this variable; referenced from native code

    // Setup activity layout
    @Override protected void onCreate (Bundle savedInstanceState)
    {
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);

        getWindow().setFormat(PixelFormat.RGBX_8888); // <--- This makes xperia play happy

        mUnityPlayer = new UnityPlayer(this);
        setContentView(mUnityPlayer);
        mUnityPlayer.requestFocus();
    }

    .........
      
    // For some reason the multiple keyevent type is not supported by the ndk.
    // Force event injection by overriding dispatchKeyEvent().
    @Override public boolean dispatchKeyEvent(KeyEvent event)
    {
        if (event.getAction() == KeyEvent.ACTION_MULTIPLE)
            return mUnityPlayer.injectEvent(event);
        return super.dispatchKeyEvent(event);
    }
  
   .........
}

可以看到UnityPlayerActivity继承自Activity，并且UnityPlayerActivity持有一个UnityPlayer实例。UnityPlayerActivity通过UnityPlayer分派native 事件。

通用的Android插件开发，通过继承UnityPlayerActivity，并使子类成为整个应用程序的LAUNCHER Activity，接下来将介绍继承UnityPlayerActivity方式的Android Plugin 。

继承UnityPlayerActivity方式的Android Plugin

Android Plugin需要包含Android项目中build后得到的app-debug.aar和Manifest.xml以及资源文件等,提供给Unity项目使用。文件存放在Unity项目中的**/Assets/Plugins/Android。Unity项目中的代码通过app-debug.aar**与封装在其中的Android代码进行交互。For more details about .aar, see Android Developer Doc. And for more information about “How Unity produces the Android Manifest”, see Unity Developer Doc

那么，接下来新建Android项目，进而生成app-debug.aar文件和Manifest.xml文件。

Android端的操作

新建Android 项目

1.将项目切换成project的视图，打开app目录下的build.gradle文件，

1.将apply plugin: ‘com.android.application’，改成apply plugin: ‘com.android.library’

2.然后删除applicationId

2.修改Manifest.xml文件

在activity中添加

<meta-data android:name="unityplaer.UnityActivity" android:value="true"/>

引入Unity的classes.jar包

从Unity 的安装目录找到unity的classes.jar包。
Windows目录：

C:\ProgramFiles\Unity\Editor\Data\PlaybackEngines\AndroidPlayer\Variations\mono\Release\classes.jar
Mac下目录：

/Applications/Unity/PlaybackEngines/AndroidPlayer/Variations/mono/Release/Classes\classes.jar
​将其拷贝到UnityAndroid项目app目录下的libs目录下，右键Add as library，导入之后可以发现在build.gradle中就有他的引入了。

编写Android项目与Unity项目交互的代码

首先需要让MainActivity继承UnityPlayerActivity,同时删除onCreate方法中的setContentView()

public class MainActivity extends UnityPlayerActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
    //示例1：
    //Unity端调用该函数
    public void ShowToast(final String msg){
        // 需要在UI线程下执行
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(),msg, Toast.LENGTH_SHORT).show();
                new AlertDialog.Builder(MainActivity.this).setMessage(msg).show();
            }
        });
    }
    //示例2：
    //Unity端调用该函数
    public void setUnityText(){
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(),"Android 端调用setText", Toast.LENGTH_SHORT).show();
                //调用Unity端函数
                UnityPlayer.UnitySendMessage("Canvas","setText","Android 端调用setText");
            }
        });
    }

}

Build得到app-debug.aar文件和Manifest.xml文件

分别在/app/build/outputs/aar和/app/src/main目录下

接下来需要将app-debug.aar用解压软件打开，并且删除libs目录下的classes.jar

Unity端的操作

创建Unity项目

新建Unity项目，并新建如下目录将Android端得到的app-debug.aar文件和Manifest.xml文件放在**/Plugins/Android**目录下,同时在Hierarchy下按照图示新建Canvas,Button和Text：

编写C#脚本

同时新建名为AndroidTest.cs的C#脚本：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class AndroidTest : MonoBehaviour {


    // Use this for initialization
    void Start () {
		
	}
	
	// Update is called once per frame
	void Update () {
		
	}
	public void BtnShowMessage()
	{
        using (AndroidJavaClass jc = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        {
            using(AndroidJavaObject jo = jc.GetStatic<AndroidJavaObject>("currentActivity"))
            {
                // 调用Android端方法
                jo.Call("ShowToast", "Unity调用了Android中的AlertDialog");
            }
        } 
	}

    public void BtnSetText()
    {
        using (AndroidJavaClass jc = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        {
            using (AndroidJavaObject jo = jc.GetStatic<AndroidJavaObject>("currentActivity"))
            {
                // 调用Android端方法
                jo.Call("setUnityText");
            }
        }
    }

	//Android端调用该方法
	public void setText(string result){
		Text text = GameObject.Find ("UnityText").GetComponent<Text> ();
		text.text = result;
	}

}

编译运行

按照标号步骤进行1. 选择Build的平台->->2. 添加Scenes ->-> 3. 设置Identification ->-> 4. 设置包名和 API Level ->-> 5. 编译运行

效果展示

使用AAR或JAR方式的Android Plugin

Android端的操作

在Android Studio中新建项目

1.选择Add No Activity

1. 新建Modue，选择Android Library

1. 添加AndroidPlugin.java

   import android.content.Context;
   import android.content.Intent;
   import android.content.IntentFilter;
   import android.os.BatteryManager;
   import java.text.SimpleDateFormat;
   import java.util.Date;
   
   public class AndroidPlugin
   {
       // Needed to get the battery level.
       private Context context;
   
       public AndroidPlugin(Context context)
       {
           this.context = context;
       }
   
       // Return the battery level as a float between 0 and 1 (1 being fully charged, 0 fulled discharged)
       public float GetBatteryPct()
       {
           Intent batteryStatus = GetBatteryStatusIntent();
   
           int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
           int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
   
           float batteryPct = level / (float)scale;
           return batteryPct;
       }
   
       // Return whether or not we're currently on charge
       public boolean IsBatteryCharging()
       {
           Intent batteryStatus = GetBatteryStatusIntent();
   
           int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
           return status == BatteryManager.BATTERY_STATUS_CHARGING ||
                   status == BatteryManager.BATTERY_STATUS_FULL;
       }
   
       private Intent GetBatteryStatusIntent()
       {
           IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
           return context.registerReceiver(null, ifilter);
       }
   
       //Get System Time
       public String getSysTime(){
           return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()).toString();
       }
   }

2. Build Module之后，在模块的子目录**/build/outputs/arr中得到.aar** 和 .jar

   

Unity端的操作

创建Unity项目

将得到的**.arr**(将**.arr解压就可以得到.jar**) 放在Assert目录下，可以放在任意的目录下，官方推荐使用**.aar** 。并且按照如下目录新建Canvas和Text。

编写C#脚本

编写BatteryLevelPlugin.cs :

Unity提供了两种方式与java进行交互

1. AndroidJNI 和 AndroidJNIHelper

2. AndroidJavaClass , AndroidJavaObject 和 AndroidJavaProxy

   

同时，官方推荐如下调用方式：

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class BatteryLevelPlugin{

    public static float GetBatteryLevel()
    {
        if (Application.platform == RuntimePlatform.Android)
        {
            using (var javaUnityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
            {
                using (var currentActivity = javaUnityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
                {
                    using (var androidPlugin = new AndroidJavaObject("com.hiscene.androidsysinfo.AndroidPlugin", currentActivity))
                    {
                        return androidPlugin.Call<float>("GetBatteryPct");
                    }
                }
            }
        }

        return 1f;
    }

    public static string GetSysTime() {

        AndroidJNI.AttachCurrentThread();


        IntPtr javaClass = AndroidJNI.FindClass("com/unity3d/player/UnityPlayer");

        IntPtr fid = AndroidJNI.GetStaticFieldID(javaClass, "currentActivity", "Landroid/app/Activity;");

        IntPtr obj = AndroidJNI.GetStaticObjectField(javaClass, fid);


        IntPtr pluginClass = AndroidJNI.FindClass("com/hiscene/androidsysinfo/AndroidPlugin");

        IntPtr initMethod = AndroidJNI.GetMethodID(pluginClass, "<init>", "(Landroid/content/Context;)V");

        jvalue[] jv = new jvalue[1];

        //TODO
        
        IntPtr pobj = AndroidJNI.NewObject(pluginClass, initMethod,jv);


        IntPtr enableMethod = AndroidJNI.GetMethodID(pluginClass, "getSysTime", "()Ljava/lang/String;");

        return AndroidJNI.CallStringMethod(pobj, enableMethod, new jvalue[1]);

    }

    //方式一：
    public static string GetSysTimeAndroidJNI()
    {

        AndroidJNI.AttachCurrentThread();

        IntPtr javaClass = AndroidJNI.FindClass("com/hiscene/androidsysinfo/SysTime");

        IntPtr initMethod = AndroidJNI.GetMethodID(javaClass, "<init>", "()V");


        IntPtr pobj = AndroidJNI.NewObject(javaClass, initMethod, AndroidJNIHelper.CreateJNIArgArray(new object[1]));


        IntPtr enableMethod = AndroidJNI.GetMethodID(javaClass, "getSysTime", "()Ljava/lang/String;");

        return AndroidJNI.CallStringMethod(pobj, enableMethod, new jvalue[1]);

    }

   //方式二：
    public static string GetSysTimeAndroidJavaClass()
    {
        if (Application.platform == RuntimePlatform.Android)
        {
            using (var javaUnityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
            {
                using (var currentActivity = javaUnityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
                {
                    using (var androidPlugin = new AndroidJavaObject("com.hiscene.androidsysinfo.AndroidPlugin", currentActivity))
                    {
                        return androidPlugin.Call<string>("getSysTime");
                    }
                }
            }
        }

        return "Time yyyy-MM-dd HH:mm:ss";
    }
}

编写BatteryMonitor.cs :

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class BatteryMonitor : MonoBehaviour {

    public Text batteryLevelText;
    public Text batteryLevelIcon;
    public Text sysTime;

    static readonly string BATTERY_LEVEL_100 = Char.ConvertFromUtf32(0xf240);
    static readonly string BATTERY_LEVEL_75 = Char.ConvertFromUtf32(0xf241);
    static readonly string BATTERY_LEVEL_50 = Char.ConvertFromUtf32(0xf242);
    static readonly string BATTERY_LEVEL_25 = Char.ConvertFromUtf32(0xf243);
    static readonly string BATTERY_LEVEL_0 = Char.ConvertFromUtf32(0xf244);

    // Update is called once per frame
    void Update () {
        UpdateStatusIndicators();
        sysTime.text = BatteryLevelPlugin.GetSysTime();
        
	}

    void UpdateStatusIndicators()
    {
        var currentBatteryLevel = BatteryLevelPlugin.GetBatteryLevel() * 100f;
        batteryLevelText.text = String.Format("{0}%", currentBatteryLevel);

        // Show the icon that matches the current level most closely.
        if (currentBatteryLevel >= 88)
        {
            batteryLevelIcon.text = BATTERY_LEVEL_100;
        }
        else if (currentBatteryLevel >= 63)
        {
            batteryLevelIcon.text = BATTERY_LEVEL_75;
        }
        else if (currentBatteryLevel >= 38)
        {
            batteryLevelIcon.text = BATTERY_LEVEL_50;
        }
        else if (currentBatteryLevel >= 13)
        {
            batteryLevelIcon.text = BATTERY_LEVEL_25;
        }
        else
        {
            batteryLevelIcon.text = BATTERY_LEVEL_0;
        }
    }
}

按照步骤编译运行

步骤：1. 选择Build的平台->->2. 添加Scenes ->-> 3. 设置Identification ->-> 4. 设置包名和 API Level ->-> 5. 编译运行

效果展示

源代码

https://github.com/rolyyu/UnityAndroidPlugin

参考文献

[1] https://docs.unity3d.com/Manual/PluginsForAndroid.html

[2] http://www.voidcn.com/blog/Silk2018/article/p-6632911.html

[3] http://blog.csdn.net/zhangdi2017/article/details/65629589

[4] https://www.yangzhenlin.com/unity-android-plugin/

[5] https://medium.com/@datdeveloper/how-to-make-android-plugin-for-unity-take-photo-from-camera-and-gallery-c12fe247c770

[6] http://addcomponent.com/android-native-plugin-unity/