A free app for Android, by The Simple Apps.

App Locker is a security application that allows you to lock your apps with a PIN, pattern, or password, preventing anyone from using them except you. 

This security application prevents any access to your apps, even if the person who owns the phone has the correct password. With this app, you can protect your privacy and your personal information. 

If you use the Pattern Lock, you need to make sure that the pattern you set is not a word or a phrase that is commonly used.

If you have a lot of apps that you want to protect, you can set them all to have the same password and pattern.

If you use the PIN Lock, you need to make sure that the password you set is not a word or a phrase that is commonly used.