Fullscreen & Immersive Sticky mode. Android Studio and LibGDX - android-studio

Question

I am developing a game and I want it to be in Immersive sticky and Fullscreen mode, I used the code provided by the web page Android developers: https://developer.android.com/training/system-ui/immersive?hl=es_419#EnableFullscreen
Now, I implemented the code as follows(AndroidLauncher class):
#Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if (hasFocus) {
hideSystemUI();
}
}
private void hideSystemUI() {
View decorView = getWindow().getDecorView();
decorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
// Set the content to appear under the system bars so that the
// content doesn't resize when the system bars hide and show.
| View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
// Hide the navbar and status bar
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN);
}
I used Android 9(API level 28) and technically it works, the phone's UI is hidden but there is a black space on top.
I want the app to fill the entire screen, but only the bottom part is filled while the top part is empty, I don't want the screen to scale when displaying phone UI.
I am using LibGDX and I don't know if it has something to do.
This is the AndroidManifest.xml:
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:isGame="true"
android:appCategory="game"
android:label="#string/app_name"
android:theme="#style/GdxTheme" >
<activity
android:name="arrive.further.game.AndroidLauncher"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:configChanges="keyboard|keyboardHidden|navigation|orientation|screenSize|screenLayout">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

Answer 1

For those who haven't stumbled upon it yet, there's a simple way to achieve this in one line of code using the AndroidApplicationConfiguration object:
In your AndroidLauncher class:
public class AndroidLauncher extends AndroidApplication {
#Override
protected void onCreate (Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AndroidApplicationConfiguration config = new AndroidApplicationConfiguration();
config.useImmersiveMode = true;
initialize(new YourGame(), config);
}
}