I downloaded Compass program for Android and tried to bring strong magnet close to it. The pointed remained stable, as if there was no magnet nearby.
Here is the video proof on YouTube.
I have checked other devices, including iPad Air 2 and they showed similar behavior. This is drastically differs from conventional compass behavior. Also, neither device show correct cardinal directions, except conventional compass.
Why doesn't Android compass react to magnet?
Note, that magnetic field value definitely increasing when magnet is approaching.
So, the actual question is how do they try to distinguish between Earth magnetic field and magnet's magnetic field?
Also, note, that direction shown by compass is INCORRECT relatively to conventional compass.