问题
Hi Im trying to work out the time between two dates using UIpickers and I am lost. I cannot fathom where to go to on this to get the value to plug into the label. Im not sure if I should use components or before the comparison or just after to put it in the label. Thanks for any pointers.
let calendar = NSCalendar.currentCalendar()
let userCalendar = NSCalendar.currentCalendar()
// Set up date object
let DateMakerFormatter = NSDateFormatter()
let date = NSDate()
@IBOutlet weak var toDatePicker: UIDatePicker!
@IBOutlet weak var fromDatePicker: UIDatePicker!
@IBOutlet weak var dayYearLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
@IBAction func toDatePickerAction(sender: UIDatePicker) {
var DateFormatter = NSDateFormatter()
DateFormatter.dateFormat = "dd-MM-yyyy HH:mm"
var endTime = DateFormatter.stringFromDate(toDatePicker.date)
self.dayYearLabel.text = endTime
var targetDate = endTime
println("\(endTime)")
}
@IBAction func fromDatePickerAction(sender: UIDatePicker) {
var fromDateFormatter = NSDateFormatter()
fromDateFormatter.dateFormat = "dd-MM-yyyy HH:mm"
var startTime = fromDateFormatter.stringFromDate(fromDatePicker.date)
self.dayYearLabel.text = startTime
var targetDate2 = startTime
println("\(startTime)")
}
@IBAction func getTheDateButton(sender: AnyObject) {
let calendar = NSCalendar.currentCalendar()
let datecomponents = calendar.components(NSCalendarUnit.CalendarUnitSecond,
fromDate: startTime, toDate: endTime, options: nil)
let second = datecomponents.second
let minute = datecomponents.minute
let hour = datecomponents.hour
let day = datecomponents.day
let year = datecomponents.year
println("Seconds: \(second)")
println("minutes: \(minute)")
println("hours: \(hour)")
println("days: \(day)")
println("years: \(year)")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
回答1:
You should try using some extensions to help you organize your code. Assuming that you have copied those extensions from the link above, you can do as follow:
class ViewController: UIViewController {
@IBOutlet weak var timeLabel: UILabel!
@IBOutlet weak var fromLabel: UILabel!
@IBOutlet weak var toLabel: UILabel!
@IBOutlet weak var fromDatePicker: UIDatePicker!
@IBOutlet weak var toDatePicker: UIDatePicker!
override func viewDidLoad() {
super.viewDidLoad()
fromDatePicker.date = NSDate()
toDatePicker.date = NSDate().xWeeks(1)
dateHasChanged()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
@IBAction func dateHasChanged() {
let fromDate = fromDatePicker.date.earlierDate(toDatePicker.date).zeroSeconds.zeroNanoSeconds
let toDate = toDatePicker.date.laterDate(fromDatePicker.date).zeroSeconds.zeroNanoSeconds
fromLabel.text = fromDate.formatted
toLabel.text = toDate.formatted
timeLabel.text = toDate.offsetFrom(fromDate)
}
}
As I mentioned here are the extensions from the link above:
extension NSDate {
func yearsFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitYear, fromDate: date, toDate: self, options: nil).year
}
func monthsFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitMonth, fromDate: date, toDate: self, options: nil).month
}
func weeksFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitWeekOfYear, fromDate: date, toDate: self, options: nil).weekOfYear
}
func daysFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitDay, fromDate: date, toDate: self, options: nil).day
}
func hoursFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitHour, fromDate: date, toDate: self, options: nil).hour
}
func minutesFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitMinute, fromDate: date, toDate: self, options: nil).minute
}
func secondsFrom(date:NSDate) -> Int{
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.components(NSCalendarUnit.CalendarUnitSecond, fromDate: date, toDate: self, options: nil).second
}
func offsetFrom(date:NSDate) -> String {
let yearsFromDate = yearsFrom(date)
let monthsFromDate = monthsFrom(date)
let weeksFromDate = weeksFrom(date)
let daysFromDate = daysFrom(date)
let hoursFromDate = hoursFrom(date)
let minutesFromDate = minutesFrom(date)
let secondsFromDate = secondsFrom(date)
if yearsFromDate > 0 { return "\(yearsFromDate) year" + { return yearsFromDate > 1 ? "s" : "" }() }
if monthsFromDate > 0 { return "\(monthsFromDate) month" + { return monthsFromDate > 1 ? "s" : "" }() }
if weeksFromDate > 0 { return "\(weeksFromDate) week" + { return weeksFromDate > 1 ? "s" : "" }() }
if daysFromDate > 0 { return "\(daysFromDate) day" + { return daysFromDate > 1 ? "s" : "" }() }
if hoursFromDate > 0 { return "\(hoursFromDate) hour" + { return hoursFromDate > 1 ? "s" : "" }() }
if minutesFromDate > 0 { return "\(minutesFromDate) minute" + { return minutesFromDate > 1 ? "s" : "" }() }
if secondsFromDate > 0 { return "\(secondsFromDate) second" + { return secondsFromDate > 1 ? "s" : "" }() }
return ""
}
}
And you should create another 4 extensions, one for formatting your date as desired, another one to add a calendar unit to your NSDate and two more to zero the seconds and nanoseconds from the date returned by the date pickers:
extension NSDate {
var formatted: String {
let styler = NSDateFormatter()
styler.dateStyle = .FullStyle
return styler.stringFromDate(self)
}
func xWeeks(weeks:Int) -> NSDate {
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.dateByAddingUnit(.CalendarUnitWeekOfYear, value: weeks, toDate: self, options: nil)!
}
var zeroSeconds: NSDate {
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.dateBySettingUnit(.CalendarUnitSecond, value: 0, ofDate: self, options: nil)!
}
var zeroNanoSeconds: NSDate {
return NSCalendar(calendarIdentifier: NSGregorianCalendar)!.dateBySettingUnit(.CalendarUnitNanosecond, value: 0, ofDate: self, options: nil)!
}
}
回答2:
This could be done in a much simpler way:
let dateA = NSDate() // Current date & time
let dateB = NSDate(timeIntervalSinceNow: -86400) // 1 day ago
let seconds = dateA.timeIntervalSinceDate(dateB) // 86,399.9766479731
let minutes = seconds / 60 // 1,439.99961079955
let hours = minutes / 60 // 23.9999935133259
let days = hours / 24 // 0.99999972972191
let years = days / 365 // 0.00273972528690934
Then just round the values up. Your UIDatePicker already returns a NSDate object. No need to use a date formatter unless you want to print/use the dates in a certain format.
来源：https://stackoverflow.com/questions/29270036/finding-time-between-dates-in-swift