Calculate time between Current Time and Old Time Swift - swift

Question

I am working on Date and Time where I keep a log of logged in and logged out. For e.g. Logged in time is 12:45 and Logged Out time is 1:45 so need to check the total hour's user was online. I have both time and below is the code where I am trying to check max hour's by adding but I am not getting the output I need.
//Current time
let formatter = DateFormatter()
formatter.timeStyle = .medium
formatter.dateStyle = .none
outTimeString = formatter.string(from: currentDateTime) as NSString
//LoggedIn Time
inTimeString = "12:49:50"
let inFormatter = DateFormatter()
inFormatter.dateFormat = "HH:mm:ss"
let outFormatter = DateFormatter()
outFormatter.dateFormat = "hh:mm"
let inTime = inTimeString
let date = inFormatter.date(from: inTime)!
let inStr = outFormatter.string(from: date)
print(inStr)->12:49:50
let outTime = outTimeString
let outDate = inFormatter.date(from: outTime as String)!
let outStr = outFormatter.string(from: outDate)
print(outStr)->16:10:15
//Adding 4 hour to logged in timw
let calendar = NSCalendar.current
let finaldate = date.addingTimeInterval(-4 * 60.0 * 60.0)
print(finaldate)->2000-01-01 03:19:50 +0000
Problem is I am getting the output wrong when 4 hours are added to the logged in time.
I need the total time logged in or add 4 hours to the original logged in time. Any one will do.
Help is much appreciated.

Answer 1

Calculating total time logged in.
var totalTimeLoggedIn: TimeInterval = 3600 // 1 hour
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd-MM-yyyy HH:mm:ss"
guard
let loginTimeDate = dateFormatter.date(from: "26-04-2018 12:00:00"),
let logoutTimeDate = dateFormatter.date(from: "26-04-2018 13:00:00")
else {
return
}
let timeLoggedIn = logoutTimeDate.timeIntervalSince(loginTimeDate)
totalTimeLoggedIn += timeLoggedIn
print("totalTimeLoggedIn: \(totalTimeLoggedIn.stringValue())") // totalTimeLoggedIn: 02:00:00
Extension used for printing total login time in hours:minutes:seconds.
extension TimeInterval {
/// Returns the time interval into a string value in hours:minutes:seconds (e.g. 09:15:34)
func stringValue(removeHoursIfEmpty:Bool = true) -> String {
if(self.isNaN){
return "00:00"
}
var value = self
if value < 0 {
value = 0
}
let hours:Int = Int(value / 3600)
let minutes:Int = Int((value.truncatingRemainder(dividingBy: 3600)) / 60)
let seconds:Int = Int(value.truncatingRemainder(dividingBy: 60))
if (hours > 0 || removeHoursIfEmpty == false){
return String(format: "%02d:%02d:%02d", hours, minutes, seconds)
} else {
return String(format: "%02d:%02d", minutes, seconds)
}
}
}

Answer 2

Try the below code, hopefully it will help you.
func findIntervalBtwToDate(startingDate: String, endingDate : String) -> TimeInterval {
var interval = 0.0
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm:ss"
dateFormatter.timeZone = NSTimeZone(name: "UTC")! as TimeZone
guard let endDate = dateFormatter.date(from: endingDate), let startDate = dateFormatter.date(from: startingDate) else { return interval }
interval = endDate.timeIntervalSince(startDate)
return interval
}