To give Android a proper facelift, Google challenged themselves to "create a visual language for our users that synthesizes the classic principles of good design with the innovation and possibility of technology and science." It wanted to achieve a "single underlying system that allows for a unified experience across platforms and device sizes", regardless of their form-factor and input method. Touch, voice, mouse, keyboard - Material Design takes it.
Android's new visual language is inspired by nature, physics, and the bold, graphic look of print-based design. Or in other words, a design based on the qualities of paper. When experiencing Material Design, look for material metaphors - "use of familiar tactile attributes" and "realistic lighting" to provide a "rationalized space" and a "system of motion".
Did we say something about physics? Oh, boy! Google has went borderline scholar on Material Design's animation system. "A critical aspect of motion for material design is to retain the feeling of physicality without sacrificing elegance, simplicity, beauty, and the magic of a seamless user experience." This translates to abandoning mechanical, linear movement in favor of swift, elegantly dancing elements. Objects entering the screen space move at peak velocity, as natural movement commands. "A person entering the frame of vision does not begin walking at the edge of the frame but well before it. Similarly, when an object exits the frame, have it maintain its velocity, rather than slowing down as it exits the frame." It's safe to say Google and app developers will no longer distract you with unnecessary changes in velocity.
Another big push towards making Android in tune with nature is Responsive Interaction. This means the interface elements will react to user input in a logical, predictable manner guided by principles Google has broken down to Surface Reaction (instantaneous visual confirmation at the point of contact), Material Response (transforming materials upon touch or click), and Radial Action (actions will visually connect to their input epicenter - voice enters through the mic icon, keyboard through keyboard keys, etc).
Another way in which Material Design delights users is Meaningful Transitions. "Transitioning between two visual states should be smooth, appear effortless, and above all, provide clarity to the user, not confusion." - proclaims Google, adding that "as transitioning elements move around the screen, they should behave in a coordinated manner. The paths elements travel along should all make sense and be orderly."
To make apps look beautiful and appealing and make you want to touch them more and more, Google urges designers and developers to use animations beyond obvious ways. "A menu icon that becomes an arrow or playback controls that seamlessly change from one to the other serve dual functions: to inform the user and to imbue your app with a moment of wonder and a sense of superb craftsmanship." That's some Apple talk right here!
Don't like muted colors and flat design? Too bad - this is the future. According to Google, Material Design's color representation is all about "bold color statements juxtaposed with muted environments, taking cues from contemporary architecture, road signs, pavement marking tape, and sports courts." Bold shadows and highlights, unexpected and vibrant colors are in tow. App menus will, generally, adhere to a palette of three colors - primary, secondary, and accent. Grey text, icons, and dividers will use alpha values instead of solid colors for better representation.
In terms of typography, Android's signature Roboto font is still the king. But it has been given a new set of clothes as well - it's now wider and rounder, clearer and "more optimistic".
Can you see them? These are Android's new icons - "simple, modern, friendly, and sometimes quirky", as described by Google. Designers will be playing with symmetry and consistency of shapes to give icons an unique quality. Round curves will trump over sharp, dangerous corners. Bear in mind, though - "consistency is important". Thus, developers are urged to use Android's system icons whenever possible across different apps.
Google is taking the paper mantra very, very seriously. App designers must switch to thinking of each pixel (with the exception of system/status bars) as if its residing on a sheet of paper. Layouts will be arranged like paper sheets, which are joined by seams, moving and overlapping together. You really have to see it in action to understand what the philosophy is about. What's most important, however, is that Google has laid down strict principles on how different windows and menus should be behaving. Hopefully, this will lead to seamless, uniform apps.
Google has went off the deep end in making Android a smart, elegant, user-centric operating system. The underlying principles and philosophies are incredibly complex and deep. We are seeing Google take forceful, decisive action to give Android a distinct, finished look - one that leaves absolutely zero doubt which operating system you're using.