How can I determine if iPhone is set for 12 hour or 24 hour time display?

Question

I thought I saw something answering this on SO recently but now I can\'t find it. Here is the code I am using now to determine if settings are for 24 hour time display. It

Answer 1

I gave Dave's answer a shot, but when testing with German locale - a region where 24 hour time cycle is used - I realized it would be better to check for H or k in the format string instead of a, and that quoted substrings should be ignored.

For German locale I get back "HH a" when requesting the date format for template "j" in the iOS simulator, and "HH 'Uhr'" on the device. (Do not understand why there is a difference at all.)

Here is a category for NSLocale that I use to check for 24 hour time cycle:

@interface NSLocale (TwentyFourHourTimeCycleCheck)

- (BOOL)uses24HourTimeCycle;

@end

@implementation NSLocale (TwentyFourHourTimeCycleCheck)

- (BOOL)uses24HourTimeCycle
{
    BOOL uses24HourTimeCycle = NO;

    NSString *formatStringForHours = [NSDateFormatter dateFormatFromTemplate:@"j" options:0 locale:self];
    NSScanner *symbolScanner = [NSScanner scannerWithString:formatStringForHours];

    NSString *singleQuoteCharacterString = @"'";

    // look for single quote characters, ignore those and the enclosed strings
    while ( ![symbolScanner isAtEnd] ) {

        NSString *scannedString = @"";
        [symbolScanner scanUpToString:singleQuoteCharacterString intoString:&scannedString];

        // if 'H' or 'k' is found the locale uses 24 hour time cycle, and we can stop scanning
        if ( [scannedString rangeOfString:@"H"].location != NSNotFound ||
             [scannedString rangeOfString:@"k"].location != NSNotFound ) {

            uses24HourTimeCycle = YES;

            break;
        }

        // skip the single quote
        [symbolScanner scanString:singleQuoteCharacterString intoString:NULL];
        // skip everything up to and including the next single quote
        [symbolScanner scanUpToString:singleQuoteCharacterString intoString:NULL];
        [symbolScanner scanString:singleQuoteCharacterString intoString:NULL];
    }

    return uses24HourTimeCycle;
}

@end