upgrade an existing Android application

I have an existing interface in which a picture is taken when installed and saved. Then a pin is set up for future purpose. After this, all the apps present in the phone are listed with an ON/OFF button beside each. My requirement is when i select ON for an application (example - facebook), and then open that application (facebook) it should open camera. For all the applications which have ON button selected, when user tries to open that particular app, camera should be opened. I am attaching the interface picture for your understanding. Remember, this is a very urgent requirement and needs to be done in just couple of days.