Create a custom activity

To extend the default Unity activity, you create your own custom activity and set it as the application’s entry point. The process to do this is as follows:

1. Create a new activity that extends the UnityPlayerActivity class.
2. Create a plug-inA 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 deliver the new activity to the final Unity Android application.
3. Override the Android App Manifest to set your new activity as the application’s entry point.

After you do this, you can implement custom behavior in your activity to control interactions between Unity and Android.

Create a new activity

To create a new activity:

1. In the Assets folder, create a new Java (.java) or Kotlin (.kt) file.
2. In the new file, create a class that extends UnityPlayerActivity.
3. In the new class, override the various base Activity methods to implement the custom behavior you want your activity to have. For more information, refer to Android’s Activity documentation.

Example activity

The following code sample shows an example activity that overrides multiple functions.

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) {
    // Calls UnityPlayerActivity.onCreate()
    super.onCreate(savedInstanceState);
    // Prints debug message to Logcat
    Log.d("OverrideActivity", "onCreate called!");
  }
  public void onBackPressed()
  {
    // Instead of calling UnityPlayerActivity.onBackPressed(), this example ignores the back button event
    // super.onBackPressed();
  }
}

Create a plug-in for the activity

To use a custom activity for a Unity Android application, you must create a plug-in to contain the activity. Activities are written in either Java or Kotlin, which means you must use one of the following types of plug-ins:

• Android Library Project/Android Archive plug-in
• JAR plug-in
• Java and Kotlin source plug-ins

If you want to create a custom activity for a single project, use Java and Kotlin source plug-ins. To create the source plug-ins, place the source files directly in the Assets folder of your project.

If you want to reuse the activity in multiple projects or distribute it to other people, use Android Archive (AAR) or JAR plug-ins. Managing one AAR or JAR plug-in file is easier to deliver functionalities in multiple projects.

Use an Android Library Project while you develop the plug-in and then compile it into an Android Archive plug-in when you complete the implementation, want to use it in multiple projects, or distribute it to other people.

After you create the plug-in, add the activity file to it.

Set the new activity as the application entry point

After you create an activity and add it to a plug-in, you can set it as the application entry point. To do this, modify the Android Manifest and set the name attribute of the activity element to the class name of your custom activity.

The following Android Manifest example shows how to do this:

<?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:theme="@style/UnityThemeSelector"
             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>