Holo vs Material Design
ホロ / マテリアルデザイン
Both sit in Google UI, so the question is not what they belong to but how they behave. Both are read here as style. They are reached for with some of the same intent, which is where they get confused.
Holo
Google's design language for Android, introduced with 3.0 and pushed so hard that carrying it unmodified became a compatibility requirement for every 4.0 device. It rules a black ground with hairlines and lets a single cyan blue carry selection, focus and progress. It arrived as a guarantee as much as a look, since an app that asked for the theme by name would be drawn the same way even on a phone wearing a manufacturer's skin.
Material Design
A design system that reduces the physical metaphor of paper and ink to rules of shadow and overlap. Elements are given elevation, shadow states the hierarchy, and motion carries physical cause and effect. It became the model for UI design being distributed as a system.
| Holo | Material Design | |
|---|---|---|
| Era | 2011–2014 | 2014– |
| Family | Google UI | Google UI |
| Kind | Style | Style |
| Cues | White text on black, with sections divided by one pixel hairlines instead of filled panels / A single cyan blue at #33B5E5 lighting only selection, the underline of a text field, and progress / A full width action bar pinned to the top, and a strip of Back, Home and Recents keys at the bottom / Tab labels and list section headers set in bold, all uppercase | Hierarchy and shadow expressed by elevation / Surfaces overlapping like sheets of paper / Motion that shows cause and effect / A standardized unit of spacing |
| Best used for | Recreating an Android app screen from roughly 2011 to 2013 with the period's actual widgets and theme names · Building hierarchy in a dark admin screen from hairlines and one accent color, without adding panels or shadows | Distributing consistent behavior across several platforms · Communicating the depth of a hierarchy visually |
| Type | One geometric leaning sans across the whole interface, in two weights only. Tabs and section headers go uppercase with the tracking opened slightly. | Build the hierarchy from one type family and separate levels by weight and size. |
| Composition | A full width action bar is fixed at the top and a single column list fills the space under it. Sections are separated by hairlines rather than white space, and a strip is reserved at the bottom for the navigation keys. | Place elements on a grid of multiples of 8 and standardize the spacing. |
| Material | Ground is black or a pale #F3F3F3, text is white or dark gray, and rules are one pixel of white at reduced opacity. Restrict the accent to #33B5E5 alone and let it glow only on press, selection and progress. | Give surfaces elevation and show front and back by the density of the shadow. |
| Caution | Redrawing the widgets so they no longer inherit from the theme throws away the one thing this style buys you, which is looking identical across devices, and leaves your app the odd one out on a skinned phone. | Do not add shadow as decoration. The moment the elevation rules break, the hierarchy is telling a lie. |