Live app icons on smartphones?

Question

One thing on my iPhone that always makes me wonder is the Clock app icon. As far as I know, it is the only app icon that is actually "live" (constantly changing state to show the current time). There is also the Settings icon, with gears rotating, although only when updating. On Android, I don't know any app with this kind of behaviour, besides Calendar showing the current date.

I could not find any information regarding this feature in Apple Human-Interface Guidelines. I am not an iOS developer, so I am not sure whether this is even accessible to third-part developers or it is just reserved for system apps.

Basically I am curious about the UX implications of this feature. Is there any study regarding "live" app icons? Why don't Apple/Google or designers use it for more app icons?

(Also, do feature has a specific name? I used "live" based on Microsoft's live tiles.)

Answer 1

The fact that it doesn't appear to be in the guidelines, and also I've never seen a third-party app with a "live" app icon would lead me to believe that they (thankfully) do not make that available to third-party developers.

With iOS 14, however, they did implement something (which Android has had for a while now) to accomplish a similar "live" effect: widgets. These are significantly larger than an app icon's size, so there is sufficient room to convey a useful amount of up-to-date, relevant data. I haven't looked into the restrictions placed on developers for capabilities and limitations of widgets, but from what I've seen so far, they appear to be mostly static text and/or images—not so much in the way of animations, like your iOS-native examples.