Editor's Review
Handing your unlocked phone to somebody - a child who wants a game, a colleague who wants to see a photo - is where Android's single screen lock stops helping. Trusted Tools' App Lock adds a second gate in front of whichever apps you choose. Messaging, gallery, banking, social accounts and settings can each be put behind a PIN, a pattern or a fingerprint, so the phone stays usable while the private parts of it stay shut.
The extras go further than most competitors. A photo and video vault moves selected media out of the gallery entirely. Intruder capture takes a front-camera shot after failed unlock attempts. A fake cover option can make a locked app appear to have crashed, which deflects a nosy person more effectively than a password box does. Themes and a choice of lock styles round it out.
Two structural caveats apply to every app in this category and to this one in particular. First, it needs powerful permissions - usage access, overlay drawing, and on some devices accessibility - to detect which app is opening and to paint the lock screen over it. That is inherent to how app locking works on Android, but it is a lot of trust to hand a utility. Second, the app is free and monetised with advertising, and the volume of ads is the most common complaint in its reviews despite the 4.67 average. Vault contents also live inside the app's own storage, so uninstalling before exporting your files loses them.
Features
PIN, pattern or fingerprint lock applied to any installed app
Photo and video vault that removes media from the main gallery
Intruder selfie captured after failed unlock attempts
Fake crash screen that disguises a locked app as a broken one
Themed lock screens and multiple unlock styles
Locks system areas such as settings, installs and uninstalls
Recovery question or email so a forgotten passcode is not fatal
Pros
Per-app locking is far more practical than locking the whole handset
Vault and intruder capture are useful additions rather than filler
The fake crash screen deters casual snooping better than a visible prompt
Setup is quick and works on a wide range of Android versions
Cons
Requires usage access, overlay and sometimes accessibility permissions
Advertising is frequent and is the dominant complaint in user reviews
Files hidden in the vault can be lost if you uninstall without exporting first
Questions people ask
Why does it ask for usage access and permission to draw over other apps?
Both are required for the core function. Usage access lets it detect which app has just been opened, and the overlay permission lets it paint the lock screen on top before you can interact with that app.
What happens if I forget my PIN or pattern?
Set a recovery email or security question during setup. Without one, there is no way to reset the lock from inside the app, and reinstalling to clear it will take the vault contents with it.
Are photos in the vault encrypted?
The vault moves files out of the gallery and into the app's protected storage so other apps and the gallery no longer list them. Treat it as protection against casual snooping, not as a substitute for full-device encryption or a backup.
Is the app free?
The download and the locking features are free. The app is funded by advertising, with a paid option to remove ads, and the advertising load is what most negative reviews focus on.
