How To Activate OnePlus Face Unlock On OnePlus 3, OnePlus 3T, OnePlus 5 And OnePlus 5T Using Xposed Module
We all know that one of the core and popular features of the OnePlus 5T is the Face Unlock implementation. The feature was so popular that users’ demands for it pushed OnePlus to bring it to the OnePlus 5 and later the OnePlus 3/3T.
The main difference between using your face to unlock recent OnePlus phones and the Trusted Face feature that Android has had for years is that OnePlus uses a proprietary software algorithm to make it quicker and more convenient while being able (to a limited degree) to differentiate between a real face and a photo.
While it’s great to be able to quickly unlock your OnePlus phone with just your face, a quick Google search reveals that many want to extend this functionality to the OxygenOS App Lock feature. App Lock, for those of you who don’t know, is a simple way to lock certain apps behind a pin/fingerprint scanner. It’s not an innovative feature as variations of it have existed for years, but it’s certainly nice to have it built in as that means you don’t have to use a third-party app built with a performance intensive Accessibility Service or UsageStats API.
And thanks to a new open source Xposed Module, you can extend OnePlus’ Face Unlock feature to work with App Lock. All that is required is a rooted OnePlus 3, OnePlus 3T, OnePlus 5, or OnePlus 5T that is on an OxygenOS version containing the Face Unlock feature, and you also have the Xposed Framework installed on your device. Hence, If you meet up those requirements then you can follow these steps to get this module up and running.
Activate OnePlus Face Unlock With The App Lock Feature
★ First of all, download and install Xposed Module from the Xposed repository.
★ Reboot your phone so as to activate.
★ Enable face unlock in the module.
★ Activate Face Unlock in OxygenOS settings if you haven’t already.
★ Activate the App Lock feature and choose which apps you wish to lock.
All done and thus, you've successfully activated face unlock on your OnePlus device and you can now lock a specific app using face unlock
(Source)