Materials Color

As far as I'm concerned, it's always about color combinations, never about single colors. Colors only exist by virtue of other colors. White wouldn't exist without black. Green wouldn't exist without red. 

It appears that Google has the same belief.

For the UI of the Android platform, they developed a very cool online tool to test if your color combinations work or not. It's mostly about contrast, never about single colors. Should a button stand out? Can everyone read your text? You can check it here.