Where is the iPhone's Date & Time getting its time zone list

Question

I can get a list of time zones with [NSTimeZone knownTimeZoneNames], but that only gives the time zone IDs which include one or two cities in each time zone.

The Date & Time settings has a great list of cities and I have seen a few other apps that have the same if not similar lookup lists.

Where do these lists come from?

I do need to relate a picked city to its time zone like Date & Time does.

Answer 1

Only 2? On 3.1 the [NSTimeZone knownTimeZoneNames] returns an array of 401 elements, and there are much less than 200 timezones on the Earth.

I'm pretty sure "other apps" use +knownTimeZoneNames as well, since this is the only public method returning such list. Please make sure your code is correct, though.

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Settings.app uses the private CPCity API from the private AppSupport.framework. It does have San Francisco, but it's private.

You need to create your own database (the data can be copied from /System/Library/PrivateFrameworks/AppSupport.framework/all_cities_adj.plist).