iOS: How to Get A Device's Current Time To Perform An Action? [duplicate]

Question

This question already has answers here:

How to get the time in iOS Programming (5 answers)

Closed 9 years ago.

What's the best way to get the a user's current time (12:00pm etc) in order to perform an action? I have a game where I'd like to display night-time images if the current time for a user is between 8pm - 5am.

Answer 1

NSDate *currentTime = [NSDate date];

NSDateFormatter *timeFormatter = [[NSDateFormatter alloc] init];
[timeFormatter setDateFormat:@"HH"];

NSString *hourCountString = [timeFormatter stringFromDate:currentTime];

int hourCountInt = [hourCountString intValue];

//time between 8PM - 5AM.
if(hourCountInt > 20 || hourCountInt < 5)
{
    NSLog(@"display night-time images");
}

Answer 2

NSDate *currentTime = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"hh-mm"];
NSString *resultString = [dateFormatter stringFromDate: currentTime];

Answer 3

Straight way would be:

NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSCalendarUnit unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit;
NSDate *date = [NSDate date];
NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

NSInteger hour = [dateComponents hour];
NSInteger minute = [dateComponents minute];

I do like helperfunctions, so you could something like this, if you need this function more frequent and want to keep your code bit clean:

- (void) getHour:(NSInteger *)hour andMinute:(NSInteger *)minute fromDate:(NSDate *)date
{
    NSCalendar *calendar= [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSCalendarUnit unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit;
    NSDateComponents *dateComponents = [calendar components:unitFlags fromDate:date];

    *hour = [dateComponents hour];
    *minute = [dateComponents minute];
}

Then call the function like this, where hour and minute could be common class variables:

NSInteger hour, minute;
NSDate *date = [NSDate date];
[self getHour:&hour andMinute:&minute fromDate:date];