UIDatePicker with 5 min interval get date on appear with interval

Question

I have spent about 3 hours trying to get a UIDatePicker to do what I want it to do. I have it setup as an action of a UITextField to segue to a new view controller with a UIDatePicker. This is all working. I have been able to select a date and send it back to the original view controller.

The problem is that I am using 5 minute time intervals. If I don't move the date picker "wheels" and select my done button to return to the parent controller the non-interval time is returned. So 11:37 returns 11:37 when I need 11:40. However, if I change the "wheels" it returns the rounded time. The datepicker is currently showing the 5 minute intervals on appear. Any clues to lead me to the right solution? I have tried setDate and minuteInterval on the UIDatePicker on viewDidAppear to no avail. Below is the code I have been using:

protocol DatePickerDelegate {
    func datePickerDidSelect(selectedDate: String)
}

class DatePickerVC: UIViewController  {

@IBOutlet weak var pickerView: UIDatePicker!

var selectedDate = ""
var delegate : DatePickerDelegate?


override func viewDidLoad() {
    super.viewDidLoad()
}

override func viewDidAppear(_ animated: Bool) {
    //setDate()
    //Have tried using setDate and minuteInterval here
}

func formatDate() -> DateFormatter {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "MMM d, yyyy h:mm a"
    return dateFormatter
}

func setDate() {
    let dateFormatter = formatDate()
    selectedDate = dateFormatter.string(from: pickerView.date)
    self.delegate?.datePickerDidSelect(selectedDate: selectedDate)
    print(selectedDate)
}

@IBAction func datePickerChanged(_ sender: Any) {
    setDate()
}

@IBAction func doneBtnPressed(_ sender: Any) {
    self.dismiss(animated: true, completion: nil)
}

@IBAction func cancelBtnPressed(_ sender: Any) {
    self.dismiss(animated: true, completion: nil)
}
}

Answer 1

you could check the date and round it to your needs like this:

override func viewDidLoad() {
    super.viewDidLoad()

    let calendar = Calendar.current
    var dateComponents = calendar.dateComponents([.month, .day, .year, .hour, .minute], from: datePicker.date)
    guard var hour = dateComponents.hour, var minute = dateComponents.minute else {
        print("something went wrong")
        return
    }

    let intervalRemainder = minute % datePicker.minuteInterval
    if intervalRemainder > 0 {
        // need to correct the date
        minute += datePicker.minuteInterval - intervalRemainder
        if minute >= 60 {
            hour += 1
            minute -= 60
        }

        // update datecomponents
        dateComponents.hour = hour
        dateComponents.minute = minute

        // get the corrected date
        guard let roundedDate = calendar.date(from: dateComponents) else {
            print("something went wrong")
            return
        }

        // update the datepicker
        datePicker.date = roundedDate
    }
}

feel free to ask if anything is unclear!

Answer 2

Another alternative is to create an extension that allows you to tweak intervals on the date value that's set when the UIDatePicker is initialized.

extension Date {
    var nearest30Min: Date {
        var dateComponents = Calendar.current.dateComponents([.year, .month, .day, .hour, .minute], from: self)
        guard let hours = dateComponents.hour else { return self }

        switch dateComponents.minute ?? 0 {
        case 0...14:
            dateComponents.minute = 0
        case 15...44:
            dateComponents.minute = 30
        case 44...59:
            dateComponents.minute = 0
            dateComponents.hour = hours + 1
        default:
            break
        }

        return dateComponents.date ?? self
    }
}

After your UIDatePicker is initialized, you could update the datePicker's value with the following code:

datePicker.setDate(datePicker.date.nearest30min, animated: false)