Editor's Review
Handing someone your unlocked phone should not mean handing over your messages. That is the whole argument for an app locker, and AppLock Pro covers it competently: choose which apps require a second unlock, pick a PIN, pattern or fingerprint, and everything else on the phone stays freely accessible.
The extras are where these apps differentiate themselves. AppLock Pro adds a private vault that moves photos and videos out of the gallery, intruder capture that photographs whoever fails an unlock, and disguise options that make a locked app appear to have crashed rather than announcing that it is protected. Themes let you change the lock screen's appearance, which sounds trivial but makes a shared phone feel less accusatory.
Two things are worth understanding. First, an app lock is a barrier against casual snooping by people who already have your phone in their hands, not a defence against someone with the technical ability to pull data off the device. Second, tools in this category need permissions that look alarming, particularly accessibility and usage access, because that is how they detect which app is opening. App Lock LLC has 100M+ installs behind it and a 4.43 rating, which is reassuring, but grant those permissions knowingly. The free version is ad-supported and the ads are noticeable.
Features
Per-app locking with PIN, pattern or fingerprint
Private vault that hides photos and videos from the gallery
Intruder selfie captured after a failed unlock attempt
Fake crash and disguised cover screens for locked apps
Customisable lock screen themes
Optional locking of system settings and installers
Pros
Straightforward setup that takes a couple of minutes
Fingerprint unlock keeps the friction low for apps you open often
Vault removes sensitive images from the shared gallery view
Disguise modes avoid advertising that something is hidden
Widely installed and actively maintained
Cons
Requires accessibility and usage-access permissions to function
Ads in the free version appear after unlock actions
Protects against casual snooping only, not determined data extraction
