Partial lock - Prevents the CPU from sleeping (not forever on most devices).
KeepAlive lock - Prevents the screen and CPU from turning off unless the user clicks on the power button.
Thank you for your reply; I had to use KeepAlive. I started with the Sinclair Z80 in the 80s and after windows, linux, on pc, raspberry, arduino, microcontrollers ... with basic, prawns3, python, Csharp, lua..., I start with B4A under android.
With my backgrounds, B4A saves me a lot of time and I congratulate you for this important work.