在ios区域是“英国”时如何获取系统时间格式？

这使用一个特殊的日期模板字符串“j”.根据ICU Spec,“j”…

Requests the preferred hour format for the locale (h,H,K,or k),as determined by whether h,or k is used in the standard short time format for the locale. In the implementation of such an API,‘j’ must be replaced by h,or k before beginning a match against availableFormats data. Note that use of ‘j’ in a skeleton passed to an API is the only way to have a skeleton request a locale’s preferred time cycle type (12-hour or 24-hour).
That last sentence is important. It “is the only way to have a skeleton request a locale’s preferred time cycle type”. Since NSDateFormatter and NSCalendar are built on the ICU library,the same holds true here.

所以我改变了我的代码中的templet值

#pragma mark
#pragma mark - get system time
-(BOOL)getSystemTimeFormat
{
    NSString *strDateFormate = @"j";
    NSString *dateFormat = [NSDateFormatter dateFormatFromTemplate:strDateFormate options:0 locale:[NSLocale currentLocale]];
    if ([dateFormat rangeOfString:@"a"].location != NSNotFound)
    {
        [kNSUserDefaults setBool:YES forKey:@"TimeFormat"];
        [kNSUserDefaults synchronize];
        return YES;
    }
    else
    {
        [kNSUserDefaults setBool:NO forKey:@"TimeFormat"];
        [kNSUserDefaults synchronize];
        return NO;
    }

}

我从以下链接How can I determine if iPhone is set for 12 hour or 24 hour time display?找到了这个解决方案.