How to Hide Black Bar/Soft Keys in Android 8.0?

[Crickpop]

My Xperia X Compact recently updated to Android 8.0 (Oreo).  With Nougat, the soft keys/black bar navigation would auto hide until I swiped down from the top of the screen.  This allowed for me to see all of my already small screen.  It was a great feature!   But with this latest update, the soft keys/black bar at the bottom of the screen are now always there.  

Now I have lost 1cm of valuable screen real estate with this latest update.  Why was this change implemented?  Is it a bug?  I can't imagine why some developer would actually want to make someone's screen smaller on purpose.

Unless I choose to root my phone, I haven't been able to locate an option to simply turn on some sort of Immersive Mode.  I've installed the paid version of Nova Launcher, and that doesn't work to remove the black bar at the bottom.  I contacted Nova about this, and they told me that feature is only available in Nova to S8/S8+/Note8/S9/S9+ users. They also said that  it's actually a work around for a bug that Samsung introduced.

I also installed the GMD Full Screen app, but I am finding that it's clunky with the keyboard issues.  So that's not an option for me.

I can't revert back to Nougat, but I sure would if I could.  Can someone please tell the developers to (at the very least) give us an OPTION whether or not we'd like to have the black bar/soft keys persistent at the bottom of the screen?  

[reikar]

I'm not sure it was enabled by default for home screen in nougat, as far as I remember.
But if you want to use immersive mode for certain apps, or even on system UI, you can try this app:
https://play.google.com/store/apps/details?id=jp.sakeapps.immersivesettings
There are also ADB command if you don't want the app, but app does basically some thing in the background.

"# Caution
Before using this application, you need to grant "WRITE_SECURE_SETTINGS" permission via ADB.
>> adb shell pm grant jp.sakeapps.immersivesettings android.permission.WRITE_SECURE_SETTINGS

Immersive mode will continue even after uninstalling this application."

[Compact4ever]

Hi!

I'm new here. I apologize in advance for my weak English.

I've the same problem as @Crickpop - "Black Bar/Soft Keys" no hiding. I think it must be a bug! Auto-Immersive doesn't work even when I'm watching some videos on full screen (so consequently it's not full screen!). I've always seen "Black Bar/Soft Keys" since I updated system to 34.4.A.2.19 or 34.4.A.2.50 (I'm not sure, I don't remember). For me it's fatal mistake! I absolutely won't want to have a root and I'm signing the Crickpop's postulate!

Sony Mobile, @Christofer, @Jonas, @Emir, @CameronT, @Emil, @ClarkLong, @Rickard or anyone from Sony Xperia Support, please do sth with it!

[DanielM_85]

Definitely this is the best solution available know to hide the navigation bar (black Bar/Soft Keys) after updating the OS to Oreo 8.0 on my xperia xa1, I was about to decide on the root, but this option is superior. Thank you very much for the advice.

Definitivamente la mejor solución disponible a la fecha para ocultar la barra de navegación luego de actualizar el OS a Oreo 8.0 en mi xperia xa1, estuve a punto de decidirme por el root, pero esta opción es superior. Muchas gracias por el consejo.