CODEWITHSUNDEEP
iosswiftuidatepicker
matcartmill
matcartmill

Reputation: 1593

Compare Current Date to DatePicker Value in Swift

In my app a user can select whether or not they are under 18 or over 18 years of age. The user enters their Date of Birth using a Date Picker. I need to make a function that will compare the current date in MM/DD/YYYY format to the DatePicker date to see if the user's entered age is over 18.

My current function for setting the DatePicker text to the associated textfield is:

func updatePicker() {
    var dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "MM/dd/yyyy"
    dob.text = dateFormatter.stringFromDate(datePickerView.date)
}

When the user tries to go the next page, the form is validated which is when I need to compare the dates and display the alert if they're under 18.

Just not sure where to start with date string evaluation.

Upvotes: 0

Views: 3550

Answers (4)

Otabek Tuychiev
Otabek Tuychiev

Reputation: 1

Firstly, you have to get parts of date as Int type using Calendar component methods:

// Current date
let currentDate = Date()
let calendar = Calendar.current
                
let currentYear = calendar.component(.year, from: currentDate) //year: Int
let currentMonth = calendar.component(.month, from: currentDate) //month: Int
let currentDay = calendar.component(.day, from: currentDate) //day: Int


// DatePicker's date
let yearFromDatePicker = calendar.component(.year, from: datePicker.date) //year: Int
let monthFromDatePicker = calendar.component(.month, from: datePicker.date) //month: Int
let dayFromDatePicker = calendar.component(.day, from: datePicker.date) //day: Int

and then you can compare parts of the date with each other based on your conditions.

Upvotes: 0

Daij-Djan
Daij-Djan

Reputation: 50089

don't convert the date to text and later convert the text to the date again. just keep the date from the datePicker around till you need it for the validation.

have a member variable var selectedDate : NSDate?

then later to check if older than 18 just do

if let userDate=self.selectedDate {
    if(NSDate().timeIntervalSinceDate(userDate) >= (568024668 /*18 years in seconds*/) {
        .... /*is 18*/
    }
}

Upvotes: 0

Leo Dabus
Leo Dabus

Reputation: 236305

You can use NSCalendar components method and extract NSCalendarUnit.CalendarUnitYear difference from two dates:

extension NSDate {
    var is18yearsOld:Bool {
        return NSDate().yearsFrom(self) > 18
    }
    func yearsFrom(date:NSDate)   -> Int { return NSCalendar.currentCalendar().components(NSCalendarUnit.CalendarUnitYear, fromDate: date, toDate: self, options: nil).year }
}

let dob1 = NSCalendar.currentCalendar().dateWithEra(1, year: 1970, month: 3, day: 27, hour: 7, minute: 19, second: 26, nanosecond: 0)!
let dob2 = NSCalendar.currentCalendar().dateWithEra(1, year: 2000, month: 3, day: 27, hour: 7, minute: 19, second: 26, nanosecond: 0)!
let is18years1 = dob1.is18yearsOld    // true
let is18years2 = dob2.is18yearsOld    // false

Upvotes: 0

Teja Nandamuri
Teja Nandamuri

Reputation: 11201

Use this function to compare date

func compareDate(date1: NSDate!, toDate date2: NSDate!, toUnitGranularity unit: NSCalendarUnit) -> NSComparisonResult

see this question

Upvotes: 0

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