How to handle touch event anywhere (Out of Activity)

Hello all. I want to do something like run a service in background and handle touch events anywhere in the screen.
Some event will trigger the click and it will perform the same action as human finger click performs.

Target area is anything and everything in entire android phone say home screen/app screen/apps etc.

Say, i will have the x,y co-ordinates and dispatch touch event.
So according to the x,y coordinates touch event must be handled.Any button/edit field etc will perform the same action as it does on human finger touch.

please give me some direction. is following method is the starting of this?

Instrumentation instrumentation = getInstrumentation();

dispatchTouchEvent() api

It wrks within same activity. not out of the activity. i need everywhere.