How to customize the keyboard skin of Google's Input Method on Android?

I need to change the android's default Google input method's skin, including the buttons' style and image, background color, and maybe delete one or two button or make them to perform a different action when clicked.

Default Input Method:

I want to change it to the style:

Is it possible to customize system's input method? Any article to read? What classes to edit?

And actually what I want to modify is the Google's default Chinese Pinyin Input Method, which looks almost the same to the English input keyboard. If you know there was a difference to modify this form the English k开发者_Go百科eyboard, please tell me too.

Thank you !

A1. Yes, it's possible.
A2. refer to developer.android.com
A3. It depends's the Pinyin implementation and your request. As I know the 'res' folder you have to modify(Ex. colors.xml you have to modify it first.). So, you have to get pinyin IME source code first.