问题
I have managed to read the web service to get current time of any given city. I could get 2 important values from web service, current time (String) and the offset.
Question is How to set time of any given city correctly?
Option 1:
- Read machine/local time
- Calculate UTC/GMT time out of machine time
- City time = UTC time +/- offset value
- But then what happens when machine time is wrong? You will also got wrong time right?
Option 2:
- Read current city time in String (2012-11-24 19:30)
- Parse this time value and set it into Calendar
- We got correct City time
- But how about the next minute? Of course requesting the web service every minute to get current time is not a good solution right? Is it possible to maintain this Calendar instance keep running automatically every minute once we set it?
NB : I'm developing Android clock widget here.
Thanks
回答1:
Option 1 is far better, in my eyes. Most cell phones have amazingly accurate time as time synchronization is an integral part of GSM and CDMA. Beyond that, I would far prefer a clock to work offline than to require internet connectivity.
If you are worried about ensuring accuracy in the face of incorrect system time, consider placing a call to a web service to get the current time for verification.
This verification could be done in the background, but keep in mind that web services are not the best time sync providers. I would let anything with under 5 minute difference go as it could be due to your server being out of sync or the call taking too long.
来源：https://stackoverflow.com/questions/13547720/how-to-get-current-time-on-another-city-correctly