When it comes to building Android apps, it's just as important for developers to consider the aspect of the app's design as it is for them to lock down and lay out a marketing and app monetization plan. Now with the release of Android 5.0 Lollipop, Google has changed the design guidelines from the previous version of Android, and along with the new guidelines came a new look, called Material Design. In a recent post on the Android developers website, Google describes a brief overview of using the new Material Theme for the design inside of your app.
They detail what using the Material Theme provides for developers, which includes a few different key pieces like system widgets with changeable color palettes, touch feedback for those system widgets, and of course the most visual part of the whole thing, the transition animations for activities, like for example tapping on the floating action button or switching back and forth between pages inside your app. The material Theme is also broken up into two different types, which consists of a light material theme and a dark material theme. As a developer, it'll be up to you to decide which theme will mesh better with your chosen app color theme to provide the most visually appealing experience for users.
For developers to make their app more material, customization of the color palette is an important part as this is one of the defining design points of Android Lollipop and Material Design. Google states that developers can customize the color palette by customizing the theme's base colors to fit the brand of the app. As an example, think of the way Google has used the red color theme to represent Gmail in the latest version. Google also mentions that to do this, developers will need to define their custom colors using theme attributes when they inherit the material theme. For a reference of the code see the image below. Another big piece and perhaps the most important since this is where most of the color for your theme and brand will be present is to customize the colors of the status bar. Google stresses that it's important for developers to choose a color that best fits their brand but will also give enough contrast for the white status icons in lollipop. The status bar colors are broken up into two distinct types, the primary color, and the primary color dark, which is what we see in the actual status bar where the icons are sitting. Google notes that you can customize the navigation bar down at the bottom as well, but only if you're planning on making both the status bar and the navigation bar transparent, otherwise leaving the navigation bar black and customizing only the status bar is the way to go.