Time difference between button presses swift - swift

Question

Right now I'm working on a time clock app that allows the user to punch in/out of work time. But I'm having trouble figuring out how to make that function possible.
In my model I have:
struct TimeLog {
var punchInTime: CFAbsoluteTime
var punchOutTime: CFAbsoluteTime
var timeWorked: Double
init (pInTime: CFAbsoluteTime, pOutTime: CFAbsoluteTime) {
self.punchInTime = pInTime
self.punchOutTime = pOutTime
self.timeWorked = pOutTime - pInTime
}
}
And in my view controller:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func punchInButtonPressed(sender: AnyObject) {
// not sure what actions are needed here to start the "aTimeLog" variable
}
#IBAction func punchOutButtonPressed(sender: AnyObject) {
// not sure what actions are needed here to complete the "aTimeLog" variable
}
I'm trying to complete this variable:
var aTimeLog = TimeLog(pInTime: //get the punch in time here, pOutTime: //get the punch out time here)
And once the variable "aTimeLog" is complete (the punchOutButton is pressed) I want to display a log of all of my "timeWorked" variables.
Forgive me in advance. You might be able to tell I'm just learning programming and Swift.

Answer 1

Personally, I'd keep a variable in NSUserDefaults - storing the punch in time. Then, when the punch out button is tapped, it fetches the dateTime variable from NSUserDefaults, does the needed calculation and returns the result. This caters for if a user closes the app (punch in time is remembered).
This creates an NSUserDefaults object
var punchInTime : NSUserDefaults = NSUserDefaults.standardUserDefaults()
#IBAction func punchInButtonPressed(sender: AnyObject) {
Saves the current time
punchInTime.setObject(NSDate(), forKey: "punchInTime")
punchInTime.synchronize()
}
#IBAction func punchOutButtonPressed(sender: AnyObject) {
fetches the saved time
punchInTime.objectForKey("punchInTime") as NSDate
creates a variable holding the current time so you can compare the two
var currentTime : NSDate = NSDate()
currentTime.timeIntervalSinceDate(punchInTime) // returns seconds
Now you can save the start time, end time and total working time inside, say, a dictionary with the key as the date maybe...
}
Then when you want to display all the days worked, simply loop through the dictionary :)
...hope I understood correctly

Answer 2

As one of the possible solutions, you could alter your init method as follows:
initWithStartTime (pInTime: CFAbsoluteTime)
{
self.punchInTime = pInTime
}
Then add a method like:
func workedTimeWithEndTime(pOutTime: CFAbsoluteTime) -> CFAbsoluteTime
{
return pOutTime - self.punchInTime
}
Finally you'll probably want to add "var timeLog: TimeLog!" into your view controller and initialise it in punchInButtonPressed with start time.

Answer 3

You should give your ViewController class a ref to a TimeLog class (why did you choose a struct? works too but just curious).
var timeLog: TimeLog?
Second of all you want to initialise it with a fresh one every time you punch in
#IBAction func punchInButtonPressed(sender: AnyObject) {
let now = CFAbsoluteTimeGetCurrent()
self.timeLog = TimeLog(pInTime: now)
}
So you initialise only with the pInTime, and the rest of the times are set to 0 / null. Next when you punch out you add the pOutTime and you can calculate the timeWorked.
#IBAction func punchOutButtonPressed(sender: AnyObject) {
if (self.timeLog == nil) {
return
}
self.timeLog!.punchOut(CFAbsoluteTimeGetCurrent());
println(self.timeLog!.timeWorked)
}
Since we don't use the constructor like you've created it and it needs a new function we need to change your class (use class unless you know why you want a struct).
class TimeLog {
var punchInTime: CFAbsoluteTime
var punchOutTime: CFAbsoluteTime
var timeWorked: Double
init (pInTime: CFAbsoluteTime) {
self.punchInTime = pInTime
self.punchOutTime = 0
self.timeWorked = 0
}
func punchOut(pOutTime: CFAbsoluteTime) {
self.punchOutTime = pOutTime
self.timeWorked = self.punchOutTime - self.punchInTime
}
}

Answer 4

Try this:
// run this on first action/tap
let start = Date()
// then, run this on the second time/interaction, to get the negative elapsed time
// for example: for 0.8 seconds this will return -0.8694559335708618
print("Elapsed time: \(start.timeIntervalSinceNow) seconds")