How Nav Button uses the Accessibility service

Screen recording · vn.fighttech.navbutton · 9 October 2026

Nav Button puts navigation keys (Back, Home, Recents and more) on the screen for people whose own navigation or power button is broken or hard to reach. Android only lets an app press those keys through the Accessibility service, so the app asks for it. This page shows, on a real phone, exactly what a user sees and what the service does.

Recorded on a Google Pixel with Android 17. White circles are the finger taps (Android “Show taps”). Duration about 2 min 25 s.

What the video shows

0:00 The service starts off. The home screen says the service is off. No keys are on the screen.
0:06 Prominent disclosure. “Turn on” opens a full-screen explanation before any system setting. It lists what the service does, what it never does, the anonymous usage counts, and how to turn it off.
0:16 “No thanks”. The app returns home and the service stays off. Accessibility settings are not opened.
0:20 “Agree”. Only now Accessibility settings open. The service is switched on by the user and confirmed in Android’s own dialog.
0:42 The keys appear. The bar shows over other apps.
1:00 Keys in use. In the stock Clock app, each key is tapped once and does exactly one action: Recents, Screenshot, Power menu, Home. Nothing happens unless a finger taps a key.
1:32 Floating ball style. The same service shown as one floating ball; a tap sends Back.
2:04 Turn off. The user switches the service off in Android Accessibility settings. The keys disappear and the app shows “The service is off”.

The Notifications, Quick settings and Lock screen keys use the same mechanism (one tap, one action). They are not shown in the recording so the phone’s notifications stay private.

The disclosure the user must accept

Before you turn it on. Nav Button needs the Android Accessibility service permission to work. This is the only system API that lets an app press Back, Home and Recents for you, so it can replace a broken or awkward navigation button.

What the service does

Performs the one navigation action you tap on its keys: Back, Home, Recents, notifications, quick settings, power menu, lock screen or screenshot.
Draws the key bar or floating ball on top of other apps.

What it never does

It does not read, record or collect what is on your screen.
It does not see or store what you type, including passwords.
It never taps, swipes or acts in other apps on its own.
It does not collect personal data or send screen content anywhere.
It does not change any other setting on your phone.

The app sends anonymous usage counts (for example, how many times each key was pressed) to improve reliability. It never includes screen content or anything you type.

You can turn the service off at any time in Settings → Accessibility → Nav Button.

Buttons: Agree (opens Accessibility settings) · No thanks (closes, nothing changes).

Technical summary

The service calls only performGlobalAction, and only right after the user taps a key.
canRetrieveWindowContent is false: the service cannot read the screen.
It declares no event types and handles no accessibility events, and it performs no gestures.
The keys are drawn as an accessibility overlay window. The app does not use the “draw over other apps” permission.
It is not marked as an accessibility tool (isAccessibilityTool=false).

Turn it off

Android Settings → Accessibility → Nav Button → switch off. Or open the app and use its link to Accessibility settings. Uninstalling the app also removes the service.