CODEWITHSUNDEEP
objective-ciosnsdateformatternstimezone
Moshe
Moshe

Reputation: 58107

What NSTimeZone value does an NSDateFormatter use if you don't pass it in?

What NSTimeZone value does an NSDateFormatter use if you don't pass it in? I'd like to either use the default timeZone value, or pass in a given one. I'd like to do something like this:

- (NSString *) announcementTime{
    NSTimeZone *defaultTimeZone;  // What does this become?
    [self announcementTimeInTimeZone:defaultTimeZone];
}

- (NSString *) announcementTimeInTimeZone:(NSTimeZone *)timeZone{

  NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

  [formatter setDateStyle:NSDateFormatterNoStyle];
  [formatter setTimeStyle:NSDateFormatterShortStyle];
  [formatter setTimeZone:timeZone];

  return time;
}

What time zone do I want to pass in to my announcementTimeInTimeZone: method? Perhaps [NSTimeZone defaultTimeZone] or [NSTimeZone localTimeZone]. I'm just not sure what the default is and don't see it documented anywhere.

Upvotes: 0

Views: 655

Answers (2)

Kasaname
Kasaname

Reputation: 1501

It will take a localTimeZone by default.

Upvotes: 0

Ben Trengrove
Ben Trengrove

Reputation: 8769

I could not find any documentation either but I had a play in the debugger and it looks like NSDateFormatter uses defaultTimeZone.

(lldb) p (NSTimeZone*)[f timeZone] (NSTimeZone *) $1 = 0x0a926fa0 @"Australia/Sydney"

(lldb) p (NSTimeZone*)[NSTimeZone defaultTimeZone] (NSTimeZone *) $2 = 0x0a926fa0 @"Australia/Sydney"

(lldb) po [NSTimeZone localTimeZone] (id) $2 = 0x0ab3bb10 Local Time Zone (Australia/Sydney (GMT+10:00) offset 36000)

"f" is an NSDateFormatter created just with alloc - init. As you can see the two time zones are exactly the same, stored at the same address.

Upvotes: 1

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