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Using UIPickerView as a DatePicker with minimum and maximum possible selections


Honestly, I have never really done this so I'm very much lost here. I have an app, presenting a UIPickerView with days: hours: minutes to the user.

I have to make sure that the minimum selected time is 10 minutes and maximum selected time is 7 days. If the user selects more than 7 days, the days and hours components should be reset back to 0. I also have to get the data and display it in a UILabel that's above the picker. Here's what I got in terms of code:

struct PollTime {
    let time: Int
    let description: String
}

struct PollModel {
    let days: [PollTime]
    let hours: [PollTime]
    let minutes: [PollTime]

    var currentTime: (day: PollTime, hour: PollTime, minute: PollTime)?

    init() {
        days = [Int](0...7).map { PollTime(time: $0, description: $0 == 0 || $0 > 1 ? "days" : "day") }
        hours = [Int](0...23).map { PollTime(time: $0, description: $0 == 0 || $0 > 1 ? "hours" : "hour") }
        minutes = [Int](0...59).map { PollTime(time: $0, description: $0 == 0 || $0 > 1 ? "min" : "min") }
    }

    func validateCurrenTime() -> Bool {
        guard let currentTime = currentTime else { return false }
        //if (//TODO: check to see if the currentTime falls within the specified time required.) {
           // return true
       // }
        return false
    }
}


var pollModel = PollModel()
extension PostPollVC : UIPickerViewDelegate,UIPickerViewDataSource {
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 3
    }
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        switch component {
        case 0:
            return pollModel.days.count
        case 1:
            return pollModel.hours.count
        case 2:
            return pollModel.minutes.count
        default:
            return 0
        }
    }

    func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
        return pickerView.frame.size.width / 3
    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

        let currentDate = Date()
        var dateComponents = DateComponents()

        let days = pickerView.selectedRow(inComponent: 0)
        let hours = pickerView.selectedRow(inComponent: 1)
        let minutes = pickerView.selectedRow(inComponent: 2)

        pollModel.currentTime = (PollTime(time: days, description: ""), PollTime(time: hours, description: ""), PollTime(time: minutes, description: ""))

        if days != 0 && hours != 0 && minutes != 0 && !pollModel.validateCurrenTime() {

            let alert = UIAlertController(title: "Invalid Time", message: "You must select a time greater than 10 minutes, up to 7 days.", preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default) { [weak self] action in
                //TODO: Reset the components of the picker to one less than or great than the invalid choices....
            })
            self.present(alert, animated: true, completion: nil)
        }

        dateComponents.day = days
        dateComponents.hour = hours
        dateComponents.minute = minutes

        let calendar = Calendar(identifier: .gregorian)
        let futureDate = calendar.date(byAdding: dateComponents, to: currentDate)

        print("The current date is: \(currentDate.description)")
        print("Your future date is: \(futureDate?.description ?? "")")

    }

    func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
        let label = UILabel()
        label.textColor = Colors.mainBlueColor
        label.textAlignment = .center
        label.font = UIFont(name: Fonts.OpenSans_Bold, size: 14)

        switch component {
        case 0:
            label.text = "\(pollModel.days[row].time) \(pollModel.days[row].description)"
            return label
        case 1:
            label.text = "\(pollModel.hours[row].time) \(pollModel.hours[row].description)"
            return label
        case 2:
            label.text = "\(pollModel.minutes[row].time) \(pollModel.minutes[row].description)"
            return label
        default:
            return label
        }
    }
}

Solution

  • Here is the working code. First important thing: Never forget to set the delegate and dataSource of your pickerView. I understood the absolute maximum was 7 days and not a minute more, but you can tweak the validation conditions as you'd like:

    class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    
        @IBOutlet weak var pickerView: UIPickerView!
        var pollModel = PollModel()
    
        func numberOfComponents(in pickerView: UIPickerView) -> Int {
            return 3
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            pickerView.delegate = self
            pickerView.dataSource = self
        }
    
        func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
            switch component {
            case 0:
                return pollModel.days.count
            case 1:
                return pollModel.hours.count
            case 2:
                return pollModel.minutes.count
            default:
                return 0
            }
        }
    
        func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    
            let currentDate = Date()
            var dateComponents = DateComponents()
    
            let days = pickerView.selectedRow(inComponent: 0)
            let hours = pickerView.selectedRow(inComponent: 1)
            let minutes = pickerView.selectedRow(inComponent: 2)
    
            pollModel.currentTime = (PollTime(time: days, description: ""), PollTime(time: hours, description: ""), PollTime(time: minutes, description: ""))
    
            if !pollModel.validateCurrenTime() {
    
                let alert = UIAlertController(title: "Invalid Time", message: "You must select a time greater than 10 minutes, up to 7 days.", preferredStyle: .alert)
                alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default) { [weak self] action in
                    [0,1,2].forEach { self?.pickerView.selectRow(0, inComponent: $0, animated: true) }
                    pickerView.reloadAllComponents()
                })
                self.present(alert, animated: true, completion: nil)
            }
    
            dateComponents.day = days
            dateComponents.hour = hours
            dateComponents.minute = minutes
    
            let calendar = Calendar(identifier: .gregorian)
            let futureDate = calendar.date(byAdding: dateComponents, to: currentDate)
    
            print("The current date is: \(currentDate.description)")
            print("Your future date is: \(futureDate?.description ?? "")")
    
        }
    
        func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
            let label = UILabel()
            label.textAlignment = .center
    
            switch component {
            case 0:
                label.text = "\(pollModel.days[row].time) \(pollModel.days[row].description)"
                return label
            case 1:
                label.text = "\(pollModel.hours[row].time) \(pollModel.hours[row].description)"
                return label
            case 2:
                label.text = "\(pollModel.minutes[row].time) \(pollModel.minutes[row].description)"
                return label
            default:
                return label
            }
        }
    
    
    }
    
    struct PollTime {
        let time: Int
        let description: String
    }
    
    struct PollModel {
        let days: [PollTime]
        let hours: [PollTime]
        let minutes: [PollTime]
    
        var currentTime: (day: PollTime, hour: PollTime, minute: PollTime)?
    
        init() {
            days = [Int](0...7).map { PollTime(time: $0, description: $0 == 0 || $0 > 1 ? "days" : "day") }
            hours = [Int](0...23).map { PollTime(time: $0, description: $0 == 0 || $0 > 1 ? "hours" : "hour") }
            minutes = [Int](0...59).map { PollTime(time: $0, description: $0 == 0 || $0 > 1 ? "min" : "min") }
        }
    
        private func timeBiggerThan10Minutes() -> Bool {
            guard let currentTime = currentTime else {
                return false
            }
            return currentTime.minute.time > 9 || currentTime.hour.time > 0 || currentTime.day.time > 0
        }
    
        private func timeLessThan7Days() -> Bool {
            guard let currentTime = currentTime else {
                return false
            }
            if currentTime.day.time == 7 {
                return currentTime.hour.time == 0 && currentTime.minute.time == 0
            }
            return currentTime.day.time < 8
        }
    
        func validateCurrenTime() -> Bool {
            return timeBiggerThan10Minutes() && timeLessThan7Days()
        }
    }