Extending the UnityPlayerActivity Java Code

Sections on this page:

• Extending the UnityPlayerActivity file
• Specifying Unity startup arguments from a custom UnityPlayerActivity file
• UnityPlayerActivity example file with sample manifest

Extending the UnityPlayerActivity file

When you develop a Unity Android application, you can use plug-insA set of code created outside of Unity that creates functionality in Unity. There are two kinds of plug-ins you can use in Unity: Managed plug-ins (managed .NET assemblies created with tools like Visual Studio) and Native plug-ins (platform-specific native code libraries). More info
See in Glossary to extend the standard UnityPlayerActivity class (the primary Java class for the Unity Player on Android, similar to AppController.mm on Unity iOS). An application can override any and all basic interactions between the Android OS and the Unity Android application.

To override the default activity:

• Create a new Activity which derives from UnityPlayerActivity (see Android documentation on Activity);
• Modify the Android Manifest to have the new Activity as the application’s entry point.

The easiest way to achieve this is to export your Project from Unity, then make the necessary modifications to the UnityPlayerActivity class in Android Studio.

To create a plug-in with your new Activity and add it to your Project, you must perform the following steps:

1. Extend the UnityPlayerActivity file. By default, the UnityPlayerActivity.java file is located at:
   
   

   Mac:

   /Applications/Unity/Unity.app/Contents/PlaybackEngines/AndroidPlayer/src/com/unity3d/player
   
   

   Windows:

   C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer\src\com\unity3d\player
   
   

   To extend the UnityPlayerActivity file, locate the classes.jar file included with Unity. You can find it in the installation folder (C:\Program Files\Unity\Editor\Data on Windows, or /Applications/Unity on Mac), in one of these subfolders:

   • PlaybackEngines/AndroidPlayer/Variations/mono

   • il2cppA Unity-developed scripting back-end which you can use as an alternative to Mono when building projects for some platforms. More info
     See in Glossary
     /Development

   • Release/Classes/

   Locate the file, and add classes.jar to the classpath Unity uses to compile the new Activity. Compile your Activity source file and package it into a JAR or AAR package, then copy it into your Project folder.

2. Create a new Android Manifest to set the new Activity as the entry point of your application, then place the AndroidManifest.xml file in the Assets/Plugins/Android folder of your Project.

Specifying Unity startup arguments from a custom UnityPlayerActivity file

When you extend UnityPlayerActivity, you can override String UnityPlayerActivity.updateUnityCommandLineArguments(String cmdLine) to pass startup arguments to Unity.

UnityPlayerActivity calls this method during startup. It accepts the current command line arguments, which can be null or empty, and returns a new string of command line arguments to pass to Unity.

For a general overview of Unity command line interface, see Command line arguments.

The following example demonstrates how to use this to select the Graphics API based on the current device:

package com.company.product;
import com.unity3d.player.UnityPlayerActivity;
import android.os.Bundle;
import android.os.Build;

public class OverrideExample extends UnityPlayerActivity {
    private boolean preferVulkan() {
        // Use Vulkan on Google Pixel devices
        if (Build.MANUFACTURER.equals("Google") && Build.MODEL.startsWith("Pixel"))
            return true;
        else
            return false;
    }

    private boolean preferES2() {
        // Use OpenGL ES 2.0 on devices that run Android 5.1 or older
        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP_MR1)
            return true;
        else
            return false;
    }

    private String appendCommandLineArgument(String cmdLine, String arg) {
        if (arg == null || arg.isEmpty())
            return cmdLine;
        else if (cmdLine == null || cmdLine.isEmpty())
            return arg;
        else
            return cmdLine + " " + arg; 
    } 

    @Override protected String updateUnityCommandLineArguments(String cmdLine)
    {
        if (preferVulkan())
            return appendCommandLineArgument(cmdLine, "-force-vulkan");
        else if (preferES2())
            return appendCommandLineArgument(cmdLine, "-force-gles20");
        else
            return cmdLine; // let Unity pick the Graphics API based on PlayerSettings
    }

    @Override protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
    }
}

UnityPlayerActivity example file

The following is an example UnityPlayerActivity file:

OverrideExample.java:
package com.company.product;
import com.unity3d.player.UnityPlayerActivity;
import android.os.Bundle;
import android.util.Log;

public class OverrideExample extends UnityPlayerActivity {
  protected void onCreate(Bundle savedInstanceState) {
    // call UnityPlayerActivity.onCreate()
    super.onCreate(savedInstanceState);
    // print debug message to logcat
    Log.d("OverrideActivity", "onCreate called!");
  }
  public void onBackPressed()
  {
    // instead of calling UnityPlayerActivity.onBackPressed() we just ignore the back button event
    // super.onBackPressed();
  }
}

The corresponding AndroidManifest.xml might look like the following:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.company.product">
  <application android:icon="@drawable/app_icon" android:label="@string/app_name">
    <activity android:name="com.YourPackage.name.OverrideExample"
             android:label="@string/app_name"
             android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
  </application>
</manifest>

• Added new code sample in 2019.2.
• Updated AndroidManifest example for 2019.3 Unity and up