Resistive touchscreens operate by sensing direct pressure applied by the user. It can be activated by pressing it not only with a finger but also with a stylus (unlike the competing capacitive technology).
A resistive touch screen consists of a touch layer placed on top of a standard display. The touch layer normally includes two transparent electrical layers separated by a small gap.
Pressing the display's surface causes the two separate layers to come into contact, which creates an electrical connection that can be sensed and located.