Pixbar: Modify your device’s navigation bar
Pixbar is a personalization application that allows you to modify your device’s navigation bar to have solid buttons. This app is meant for phones with stock Lollipop and above, and it works without any root permissions. Pixbar is an add-on to those that already have navigation bars and does not add a navigation bar if your phone uses physical buttons.
The app is designed to resemble a certain device that has an exclusive on these kinds of buttons. However, support for Xperia, LG, and other devices with slightly different navigation buttons will be available in a future release. With Pixbar, you can easily modify and personalize your device’s navigation bar to your liking.