Bump this question. I also need this functionality. When I try add my custom activity I get this error:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.epicgames.TheTaleOfThreeMobile/com.epicgames.ue4.GameActivity}: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.epicgames.TheTaleOfThreeMobile/com.epicgames.ue4.TestActivity}; have you declared this activity in your AndroidManifest.xml?
But I declared this activity in AndroidManifest.xml:
activity android:name="com.epicgames.ue4.TestActivity"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
android:launchMode="singleTask"
android:screenOrientation="landscape"
android:debuggable="true"
android:configChanges="orientation|keyboardHidden">
<meta-data android:name="android.app.lib_name" android:value="UE4"/>
</activity>