问题
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
回答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".
回答2:
You could make this work on a phone with a front camera with a wide angle so it can see the whole screen. You'd have to write the software for recognizing hand movements, and translate these to screen actions.
Why not just use touch, if I may ask?
来源：https://stackoverflow.com/questions/11027282/change-an-image-on-hover-without-touching-the-screen-in-android