Question

I have a very creative requirement – I am not sure if this is feasible – but it would certainly spice up my app if it could .

Premise: On Android phones, if the screen is covered by hand(not touching, just close to the screen) or if the
phone is placed over the ear during a call the phone locks or
basically it blacks out. So there must be some tech to recognize that
my hand is near the screen.

Problem: I have an image in my app. If the
user points to the image without touching the screen, just as an
extension to the premise, I must be able to know that the user is
pointing to the image and change the image. Is this possible ?

UPDATE: An example use:

Say I want to build a fun app, on touch the image leads to some other
place. For example – I have two doors one to a car and one to a lion.
Now just when the user is about to touch door 1 – the door should show
a message saying are you sure, and then actually touching it takes you
to another place. Kinda rudimentary example, but I hope you get the
point

Answer 1

The feature you are talking about is the proximity sensor. See Sensor and SensorEvent.values for Sensor.TYPE_PROXIMITY.

You could get the distance of the hand from the screen, but you won’t really be sure where in the XY co-ordinate system the hand is. So you won’t be able to figure out whether the user is pointing to the “car door” or to the “lion door”.