Mr. Cooooooooooooode

I have found an article that described the problem I have met before.

Screen have two mode - (1) portrait mode (2) landscape mode

Android uses g-sensor's value to calculate current user's view, but system design default mode is portrait mode.

It does not tell system which side is long and short.

System can not recognize right x-axis, y-axis, and z-axis of gsensor.

In the link, it will tell you more about the problem, and it also show its solution.

Just take a look: http://android-developers.blogspot.com/2010/09/one-screen-turn-deserves-another.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+blogspot/hsDu+(Android+Developers+Blog)