Watch out the difference in the new design guidelines of Google!

Google announced a guideline for new version of programming language, “MaterialDesign” for Android.
Not only buttons and menu bars, but also about ways for composition of menu, where it should exist, pattern for text to display over image preview, and so on.
Making guideline minute, it makes consistency in design and gives users comfortable UX.
http://dev.classmethod.jp/smartphone/android/google-material-design/
http://www.yasuhisa.com/could/article/material-design/