The Material Design team has an interesting blog post into what it calls the “24-hour Clock Design Challenge” that chronicles Google’s work creating a time picker for those that use a 24 ...

In any case, for the longest time, 24-hour clock users on Android have had to deal with a somewhat inconvenient interface in setting times for calendar events, appointments, and such.

While there are exactly 86,400 atomic-clock based seconds in a 24-hour day, the actual time for the earth to complete one rotation is slightly longer than 86,400 seconds.

Scroll down until you’ve come across Short time and Long time. In each, if you want to change things to the 24-hour clock, be sure the option with the 0 at the beginning.