There are lots of good ideas here. There is no way to get groups of zones from joda-time though.
One thing to look at is joda-time-I18N, which uses the CLDR data to provide some nice methods for managing time zone information including the most important zone per territory. Probably not enough for you, but it may help. Stephen On 30 November 2010 10:32, Tauren Mills <[email protected]> wrote: > I'd like to implement a UX that makes selecting an appropriate timezone very > simple. This is for a web application, but could be for any application. > When a user creates a profile, they need to select or verify their current > timezone. Instead of presenting the user with a massive list of 500+ zones > from DateTimeZone.getAvailableIDs(), I want to present them with a few very > likely options, with the most likely timezone already selected. Of course > there will still be a way for them to select "Other" to select from all > available timezones. > Here's how I see it working: > 1. Application server is accurately set to UTC and runs ntpdate regularly > 2. Web client detects user's current local time and passes it to the server > 3. Server attempts to determine timezone in several different ways: > A. Given the current server time in UTC and the user's current time in > some unknown timezone, generate a list of potential timezones > B. Server performs a timezone lookup based on IP address of > user (http://stackoverflow.com/questions/2763263/how-to-get-clients-timezone-offset-from-his-ip-address) > C. If user allows it, server performs an HTML5 geo-location and > determines timezone from lat/long > (http://stackoverflow.com/questions/41504/timezone-lookup-from-latitude-longitude) > 4. Server combines the results of options A, B, and C to generate a short > list of potential timezones the user is within, ordered from most likely to > least likely with most likely selected. > 5. User is presented with this short list of timezones, with most probable > selected and an "Other" option to pick from the entire list > In fact, I could see the UI looking something like the following site, but > simplified. The list would be comprised of many of the same timezone > aliases, such as "America/Los_Angeles", "America/Vancouver", > "America/Tijuana", etc. Your current time would be shown along with the > current time in each timezone. Each timezone alias would be selectable, with > the top most selected by default: > http://everytimezone.com/ > Obviously, the user's time is likely to be inaccurate -- certainly not the > same as the server's time. And there is the delay between when the time is > taken on the client and sent to the server for processing. So the logic > would assume that the time sent from the client could be off by minutes. The > closer their time is to accurate, the more precise the suggested timezones > would be. I'm not worried about those users who's clock is completely wrong. > > Just thought I'd ask for suggestions or comments before beginning > implementation. Sorry if this is slightly off-topic, but it does pertain to > some specific Joda questions: > 1. Are there any features of JodaTime that would significantly simplify or > help with step 3A above? > 2. Is there a way to get a list of timezone "groups" from Joda (such as > "Africa", "America", "US", "Etc", and so forth)? This would allow timezones > from "America" to be preferred over "US", as the US zones would not be given > as options. > 3. Any suggestions on how to best integrate timezone "preference" > information? For instance, as of today, it is better for a user to pick > "America/Los_Angeles" than it is to pick "US/Pacific", "PST8PDT", > "UTC-08:00", or "GMT+08:00". I'd like to only show the "preferred" > timezones. > 4. Any suggestions on how to best integrate timezone "usage" or "population" > information? For instance, if it is 12:00 noon local time and the server > says it is 20:00, then options for UTC--8:00 should be shown. But I'd like > to show "America/Los_Angeles" before "Pacific/Pitcairn". > 5. Are there any serious flaws I haven't considered in this approach? > Thanks, > Tauren > > ------------------------------------------------------------------------------ > Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! > Tap into the largest installed PC base & get more eyes on your game by > optimizing for Intel(R) Graphics Technology. Get started today with the > Intel(R) Software Partner Program. 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