PurpleLock

Password-protect your apps with PurpleLock - it's free, open source, and ad-free

PurpleLock lets you prevent unwanted access to your apps by requiring users to enter a password before using each app; you choose which apps to block.

PurpleLock is free, open source, and ad-free. It doesn't share any of your data, and it only stores the bare minimum needed for it to function.

PurpleLock is a good quick-and-dirty solution for increasing your phone's security. For example, you may want to let your friends borrow your phone but prevent them from accessing your texting app. PurpleLock is not a perfect solution; for example, the user can deactivate it using the Settings app.

PurpleLock's source code is available at https://github.com/samalws/PurpleLock. It is licensed under the GNU General Public License.