Get current iPhone device timezone date and time from UTC-5 timezone date and time iPhone app?

Question

In my iPhone application i am very struggling to convert the webservice response time to current device time. The webservice time in UTC-5 timezone. The app is

Answer 1

NSDate* currentDate = [NSDate date];

NSTimeZone* CurrentTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
NSTimeZone* SystemTimeZone = [NSTimeZone systemTimeZone];

NSInteger currentGMTOffset = [CurrentTimeZone secondsFromGMTForDate:currentDate];
NSInteger SystemGMTOffset = [SystemTimeZone secondsFromGMTForDate:currentDate];
NSTimeInterval interval = SystemGMTOffset - currentGMTOffset;

NSDate* TodayDate = [[NSDate alloc] initWithTimeInterval:interval sinceDate:currentDate];
NSLog(@"Current time zone Today Date : %@", TodayDate);

Swift 4

var currentDate = Date()
var CurrentTimeZone = NSTimeZone(abbreviation: "GMT")
var SystemTimeZone = NSTimeZone.system as NSTimeZone
var currentGMTOffset: Int? = CurrentTimeZone?.secondsFromGMT(for: currentDate)
var SystemGMTOffset: Int = SystemTimeZone.secondsFromGMT(for: currentDate)
var interval = TimeInterval((SystemGMTOffset - currentGMTOffset!))
var TodayDate = Date(timeInterval: interval, since: currentDate)
print("Current time zone Today Date : \(TodayDate)")

Hope it helps to another developers ! Happy Coding !

Answer 2

I have tested your scenario and added some code for your reference. Please test the below and please let me know it is useful for you.

NSString *dateStr = @"2012-07-16 07:33:01";
NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init]; 
[dateFormatter1 setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; 
NSDate *date = [dateFormatter1 dateFromString:dateStr];
NSLog(@"date : %@",date);

NSTimeZone *currentTimeZone = [NSTimeZone localTimeZone];
NSTimeZone *utcTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"];

NSInteger currentGMTOffset = [currentTimeZone secondsFromGMTForDate:date];
NSInteger gmtOffset = [utcTimeZone secondsFromGMTForDate:date];
NSTimeInterval gmtInterval = currentGMTOffset - gmtOffset;

NSDate *destinationDate = [[[NSDate alloc] initWithTimeInterval:gmtInterval sinceDate:date] autorelease];

NSDateFormatter *dateFormatters = [[NSDateFormatter alloc] init];
[dateFormatters setDateFormat:@"dd-MMM-yyyy hh:mm"];
[dateFormatters setDateStyle:NSDateFormatterShortStyle];
[dateFormatters setTimeStyle:NSDateFormatterShortStyle];
[dateFormatters setDoesRelativeDateFormatting:YES];
[dateFormatters setTimeZone:[NSTimeZone systemTimeZone]];  
dateStr = [dateFormatters stringFromDate: destinationDate];
NSLog(@"DateString : %@", dateStr);

Thanks.

Answer 3

May this extension would be easier.

Swift 4: UTC/GMT ⟺ Local (Current/System)

extension Date {

    // Convert local time to UTC (or GMT)
    func toGlobalTime() -> Date {
        let timezone = TimeZone.current
        let seconds = -TimeInterval(timezone.secondsFromGMT(for: self))
        return Date(timeInterval: seconds, since: self)
    }

    // Convert UTC (or GMT) to local time
    func toLocalTime() -> Date {
        let timezone = TimeZone.current
        let seconds = TimeInterval(timezone.secondsFromGMT(for: self))
        return Date(timeInterval: seconds, since: self)
    }

}


// Try it
let utcDate = Date().toGlobalTime()
let localDate = utcDate.toLocalTime()

print("utcDate - (utcDate)")
print("localDate - (localDate)")