A free app for Android, by BANANA Studio.

The Applock app is a lightweight tool that lets you lock your favourite programs with a simple click. The tool is capable of locking Facebook, WhatsApp, Gallery, Messenger, Snapchat, Instagram, Contacts, SMS, Gmail, Settings, incoming calls, and any app you choose. It also lets you hide all your notifications in the lock screen.

Applock supports multiple locking methods such as passwords and patterns, and it also has a fingerprint sensor. You can set the time for which the tool should be active.

You will never have to worry about your personal information being revealed when you are using the tool!