For android system, of course you can custom your own style and theme, but you can‘t break compatibility with AOSP.
We should follow AOSP design, and do not play trick in code. Such as, AlertDialog style, Button style, ListView style, ActionBar style.
To realize the look like what the SPEC design, png resources design is very important. Many margin effect should be made by pngs, and also the visual erea.
About custom Theme and Style,布布扣,bubuko.com
原文：http://www.cnblogs.com/haobo/p/3853998.html