Get NSDate to display a date from another timezone based on it's secondsFromGMT

Question

I am storing a record and this record has a date pumpTimeNSDate attached to it.

If the device that has created this record is placed on a different timezone from the device that is loading the record the device that is loading the record shows a different date from the date that is shown by the device that has created the record. I want them both to show the same date.

I understand that happens because the NSDateFormatter() adjusts the NSDate (which is just a reference in time) to the users current timezone taking in consideration it's distance from GMT.

How do I get a device that is loading the record in a different timezone to show the same that is getting show on the device that has created the record?

Note: originTimeOffsetObject stores how far from GMT was the device that has created the record.

    if let pumpTimeNSDate = objects[indexPath.row].objectForKey("pumpTimeNSDate") as? NSDate {

                let formatter = NSDateFormatter()
                formatter.dateFormat = "E dd, H:mm"

                if let originTimeOffsetObject = objects[indexPath.row].objectForKey("originTimeOffset") as? NSTimeInterval 
                {

                // not sure how to use originTimeOffsetObject

                }
                else
                {
                   // if timeoffset do not exist on DB
                   createdAt = formatter.stringFromDate(pumpTimeNSDate)
                }
    }

Answer 1

You create and set an NSTimeZone onto a NSDateFormatter. Since you know the offset, you can:

let dateFormatter = NSDateFormatter()
dateFormatter.dateStyle = .MediumStyle   
dateFormatter.timeStyle = .MediumStyle
dateFormatter.timeZone = NSTimeZone(forSecondsFromGMT: 0) // Update to your value
dateFormatter.stringFromDate(NSDate()) // Display your date