Send bluetooth data when back button(mobile's button) pressed


i am getting data using web api every 1 minute ,and then sends them via bluetooth to my microcontroller.
But when i press back button(or home button), the application stops working , i mean it stop sending data and get data from WEB.

i have use clock with always fire enable it to get data from web,How can i run my app even i press back or home button.

Note: it’s necessary to run app after button press
Thanks !!