Android项目集成Unity详细教程

Foreword

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上一篇介绍了Xcode项目集成Unity的步骤，本篇介绍AS项目集成Unity，其实在AS上集成相比Xcode简单多了，但也有不少坑需要注意。我们知道Unity可以直接打包apk，也可以导出AS或Eclipse工程，我的应用场景是已经有个Android Studio大项目了，Unity所做的功能属于其一部分，所以选择将Unity导出AS工程，为了方便主项目调用，还将Unity部分打包成aar。
环境：Android Studio 3.0 + Unity 2017

Step

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1.将Unity工程导出AS工程

如下图红框处，Build System选择Gradle，Export Project勾选，按图中箭头把包名填好，不能使用Unity默认的，否则导出不了，点击Export导出。

导出结果：

2.AS导入上一步的工程，选择Import project (Gradle,Eclipse ADT,etc)

导入多半是会报错的，一般错误就是gradle版本没选对，按自己的情况选好就行了，比如我的是3.0.0。

3.继承UnityPlayer

此时我们来看看这个工程结构，就一个界面UnityPlayerActivity，因为做Unity游戏的话也不需要显示其它原生界面，网上有些教程就是用继承UnityPlayerActivity的方法来显示Unity，然而这样做不够灵活。查看UnityPlayerActivity我们可以发现真正关键的是UnityPlayer所以仿照UnityPlayerActivity直接操作UnityPlayer不就好了么，但是。。。但是这里有个坑，我直接用UnityPlayer正确显示了Unity界面，可是在退出含Unity界面的Activity时，整个应用退出了，难道有Bug导致整个应用崩了？经过查找，发现原来在UnityPlayer源码中：

这个kill方法在Activity finish时会被调用，然而它竟然给我把当前应用进程杀死了！没办法，自己写个类 MyUnityPlayer 继承它，并重写父类的kill方法。

package com.unity.demo;

import android.content.Context;

import com.unity3d.player.UnityPlayer;

public class MyUnityPlayer extends UnityPlayer {
    public MyUnityPlayer(Context context) {
        super(context);
    }

    @Override
    protected void kill() {
        //不要杀死当前应用进程
    }
}

4.导出aar包

百度“Android Studio导出aar包”，发现还要创建Module，有那么麻烦吗？直接改build.gradle就行了。如下图，apply plugin: ‘com.android.application’ 改为 apply plugin: ‘com.android.library’，注释掉applicationId，然后Rebuild Project。完成后在工程的build - outputs - aar文件夹下就可以看到aar包了。

5.在主AS工程中使用unity aar包

这里我就用一个简单的Demo来演示，把aar文件放入新工程的app - libs文件夹下，修改app的build.gradle：

Demo项目用两个界面呈现，主界面和第二界面，Unity内容使用FrameLayout或LinearLayout显示，代码如下：

MainActivity.java

package com.my.unityapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {

    private Button firstButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        firstButton = findViewById(R.id.firstButton);
        firstButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                startActivity(intent);
            }
        });
    }
}

activity_main.xml

SecondActivity.java 基本就是仿照UnityPlayerActivity写的

package com.my.unityapp;

import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;

import com.unity.demo.MyUnityPlayer;
import com.unity3d.player.UnityPlayer;

public class SecondActivity extends Activity {

    private LinearLayout unityLayout;
    private Button secondButton;
    private MyUnityPlayer mUnityPlayer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);

        unityLayout = findViewById(R.id.unityLayout);
        secondButton = findViewById(R.id.secondButton);
        secondButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                SecondActivity.this.finish();
            }
        });


        getWindow().setFormat(PixelFormat.RGBX_8888); // <--- This makes xperia play happy
        // 创建Unity视图
        mUnityPlayer = new MyUnityPlayer(this);
        // 添加Unity视图
        unityLayout.addView(mUnityPlayer.getView());
        mUnityPlayer.requestFocus();

    }

    @Override protected void onNewIntent(Intent intent)
    {
        // To support deep linking, we need to make sure that the client can get access to
        // the last sent intent. The clients access this through a JNI api that allows them
        // to get the intent set on launch. To update that after launch we have to manually
        // replace the intent with the one caught here.
        setIntent(intent);
    }

    // Quit Unity
    @Override protected void onDestroy ()
    {
        mUnityPlayer.quit();
        super.onDestroy();
    }

    // Pause Unity
    @Override protected void onPause()
    {
        super.onPause();
        mUnityPlayer.pause();
    }

    // Resume Unity
    @Override protected void onResume()
    {
        super.onResume();
        mUnityPlayer.resume();
    }

    // Low Memory Unity
    @Override public void onLowMemory()
    {
        super.onLowMemory();
        mUnityPlayer.lowMemory();
    }

    // Trim Memory Unity
    @Override public void onTrimMemory(int level)
    {
        super.onTrimMemory(level);
        if (level == TRIM_MEMORY_RUNNING_CRITICAL)
        {
            mUnityPlayer.lowMemory();
        }
    }

    // This ensures the layout will be correct.
    @Override public void onConfigurationChanged(Configuration newConfig)
    {
        super.onConfigurationChanged(newConfig);
        mUnityPlayer.configurationChanged(newConfig);
    }

    // Notify Unity of the focus change.
    @Override public void onWindowFocusChanged(boolean hasFocus)
    {
        super.onWindowFocusChanged(hasFocus);
        mUnityPlayer.windowFocusChanged(hasFocus);
    }

    // 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);
    }

    // Pass any events not handled by (unfocused) views straight to UnityPlayer
    @Override public boolean onKeyUp(int keyCode, KeyEvent event)     { return mUnityPlayer.injectEvent(event); }
    @Override public boolean onKeyDown(int keyCode, KeyEvent event)   { return mUnityPlayer.injectEvent(event); }
    @Override public boolean onTouchEvent(MotionEvent event)          { return mUnityPlayer.injectEvent(event); }
    /*API12*/ public boolean onGenericMotionEvent(MotionEvent event)  { return mUnityPlayer.injectEvent(event); }
}

activity_second.xml

运行结果：

Postscript

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• 还有Unity与Android的交互问题，网上教程很多，这里就不赘述了：
  Unity调用Android，通过 AndroidJavaClass、AndroidJavaObject；
  Android调用Unity，通过 UnityPlayer.UnitySendMessage()。