Does Current Time Match a Range of times? - ios

Question

I am trying to create a catch on an iOS app to keep people from accessing things outside of a small window.
Basically, I need the action to only fire if it is between 12-1:30PM on Sundays in London (BST Time Zone). How would I check the current time, convert it to that time zone, and then see if it matches up?
I have tried the following, but it always shows it is between that range:
- (NSDate *)dateByNeutralizingDateComponentsOfDate:(NSDate *)originalDate {
NSCalendar *gregorian = [[[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
// Get the components for this date
NSDateComponents *components = [gregorian components: (NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate: originalDate];
// Set the year, month and day to some values (the values are arbitrary)
[components setYear:2000];
[components setMonth:1];
[components setDay:1];
return [gregorian dateFromComponents:components];
}
- (BOOL)isTimeOfDate:(NSDate *)targetDate betweenStartDate:(NSDate *)startDate andEndDate:(NSDate *)endDate {
if (!targetDate || !startDate || !endDate) {
return NO;
}
// Make sure all the dates have the same date component.
NSDate *newStartDate = [self dateByNeutralizingDateComponentsOfDate:startDate];
NSDate *newEndDate = [self dateByNeutralizingDateComponentsOfDate:endDate];
NSDate *newTargetDate = [self dateByNeutralizingDateComponentsOfDate:targetDate];
// Compare the target with the start and end dates
NSComparisonResult compareTargetToStart = [newTargetDate compare:newStartDate];
NSComparisonResult compareTargetToEnd = [newTargetDate compare:newEndDate];
return (compareTargetToStart == NSOrderedDescending && compareTargetToEnd == NSOrderedAscending);
}
-(void)checkDate {
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:#"EEEE HH:mm"];
NSTimeZone *timeZone = [NSTimeZone timeZoneWithAbbreviation:#"BST"];
[dateFormatter setTimeZone:timeZone];
NSDate *openingDate = [dateFormatter dateFromString:#"Sunday 12:00"];
NSDate *closingDate = [dateFormatter dateFromString:#"Sunday 1:30"];
NSDate *targetDate = [NSDate date];
if ([self isTimeOfDate:targetDate betweenStartDate:openingDate andEndDate:closingDate]) {
NSLog(#"TARGET IS INSIDE!");
}else {
NSLog(#"TARGET IS NOT INSIDE!");
}
}

Answer 1

I assume you want to use the current time as observed in England, rather than BST specifically, as BST is British Summer Time. My understanding is that, during the winter, they use UTC (formerly known as GMT). Thus we should specify the time zone in a way that will select the proper offset from UTC based on the time of year.
static BOOL dateIsAcceptable(NSDate *date) {
NSCalendar *calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
calendar.timeZone = [NSTimeZone timeZoneWithName:#"Europe/London"];
NSDateComponents *components = [calendar
components:NSCalendarUnitWeekday | NSCalendarUnitHour | NSCalendarUnitMinute
fromDate:date];
if (components.weekday != 1) {
return NO;
}
double hour = components.hour + components.minute / 60.0;
return hour >= 12 && hour < 13.5;
}