UIDatePicker: al cambiar la fecha

Question

Acabo de empezar a usar UIDatePicker en mi aplicación para iPad, pero ¿hay alguna manera de verificar cuándo se ha cambiado la fecha?

Quiero hacer algo cuando se cambia la fecha. Espero que puedas ayudar, gracias.

Answer 1

Cuando configurado correctamente, un objeto UIDatePicker envía una acción mensaje cuando un usuario acaba de rotación una de las ruedas para cambiar la fecha o el tiempo; el evento de control asociado es UIControlEventValueChanged.

Así que hay que añadir su clase para manejar UIControlEventValueChanged evento en su selector:

[picker addTarget:self action:@selector(dateChanged:) 
       forControlEvents:UIControlEventValueChanged]; 
... 

- (void) dateChanged:(id)sender{ 
    // handle date changes 
} 

Answer 2

versión rápida

override func viewDidLoad() { 
    super.viewDidLoad() 
    let picker = UIDatePicker(frame: CGRectMake(0, 0, 200, 200)) 
    picker.addTarget(self, action: #selector(datePickerChanged(_:)), forControlEvents: .ValueChanged) 
    view.addSubview(picker) 
} 

func datePickerChanged(picker: UIDatePicker) { 
    print(picker.date) 
} 

Answer 3

Swift 3 Versión:

override func viewDidLoad() { 
    super.viewDidLoad() 

    if sYourSelectedDate == "" { 
     if let plist = Plist(name: "YourPlistName") { 
      sYourSelectedDate = plist.getSingleValueInPlistFile(sFieldName: "yourSelectedDate")! 

     } 
    } 
    if sYourSelectedDateTime == "" { 
     if let plist = Plist(name: "YourPlistName") { 
      sYourSelectedDateTime = plist.getSingleValueInPlistFile(sFieldName: "yourSelectedDateTime")! 

     } 
    } 

    // add dateTimePickerChanged event (e.g., if device is powered down, values get saved) 
    self.dateTimePicker.addTarget(self, action: #selector(dateTimeChanged), for: .valueChanged); 

    // set min and max dates of datetimePicker 
    // subtracting 1 minute from current time 
    let currentTempDate = NSDate() 
    let newDate = currentTempDate.addingTimeInterval(-1 * 60); 
    let currentDate = newDate; 

    let calendar: NSCalendar = NSCalendar(calendarIdentifier: NSCalendar.Identifier.gregorian)! 

    calendar.timeZone = NSTimeZone(name: "US/Eastern")! as TimeZone 

    let components: NSDateComponents = NSDateComponents() 
    components.calendar = calendar as Calendar 

    components.year = -1 
    let minDate: NSDate = calendar.date(byAdding: components as DateComponents, to: currentDate as Date, options: NSCalendar.Options(rawValue: 0))! as NSDate 

    let maxDate: NSDate = currentDate as NSDate 

    self.dateTimePicker.minimumDate = minDate as Date 
    self.dateTimePicker.maximumDate = maxDate as Date 

    //print("minDate: \(minDate)") 
    //print("maxDate: \(maxDate)") 

    if(sYourSelectedDateTime == "") 
    { 
     // subtracting 1 minute from current time 
     let currentTempDate = NSDate() 
     let newDate = currentTempDate.addingTimeInterval(-1 * 60); 
     let currentDate2 = newDate; 

     let dateFormatter = DateFormatter() 
     dateFormatter.dateFormat = "MM/dd/yyyy h:mm a" 

     calendar.timeZone = NSTimeZone(name: "US/Eastern")! as TimeZone 

     let userCalendar = Calendar.current 
     let requestedComponents: Set<Calendar.Component> = [ 
      .year, 
      .month, 
      .day, 
      .hour, 
      .minute 
     ] 

     let dateTimeComponents = userCalendar.dateComponents(requestedComponents, from: currentDate2 as Date) 

     let iPhoneDateComponents = NSDateComponents() 
     iPhoneDateComponents.year = dateTimeComponents.year!; 
     iPhoneDateComponents.month = dateTimeComponents.month!; 
     iPhoneDateComponents.day = dateTimeComponents.day!; 
     iPhoneDateComponents.hour = dateTimeComponents.hour!; 
     iPhoneDateComponents.minute = dateTimeComponents.minute!; 
     iPhoneDateComponents.timeZone = NSTimeZone(name: "US/Eastern") as TimeZone? 

     let iPhoneDate = calendar.date(from: iPhoneDateComponents as DateComponents)! 

     self.dateTimePicker.date = iPhoneDate; 
     sYourInitialDateTime = dateFormatter.string(from: self.dateTimePicker.date); 

     if let plist = Plist(name: "YourPlistFile") { 
      plist.editSingleValueInPlistFile(dictString: "YourPlistFile", sFieldName: "yourInitialDateTime", sValue: sYourInitialDateTime) 
     } 

    } else { 
     let dateFormatter: DateFormatter = DateFormatter() 
     dateFormatter.dateFormat = "MM/dd/yyyy h:mm a" 
     let dateObj = dateFormatter.date(from: sYourSelectedDateTime) 
     self.dateTimePicker.date = dateObj! 
    } 

} 

func dateTimeChanged(picker: UIDatePicker) { 
    let dateFormatter = DateFormatter() 
    dateFormatter.dateFormat = "MM/dd/yyyy" 
    sYourSelectedDate = dateFormatter.string(from: picker.date); 
    dateFormatter.dateFormat = "MM/dd/yyyy h:mm a" 

    sYourSelectedDateTime = dateFormatter.string(from: picker.date); 

    if (sYourSelectedDateTime == sYourInitialDateTime) 
    { 
     sYourSelectedDate = ""; 
     sYourSelectedDateTime = ""; 
    } 

    if let plist = Plist(name: "YourPlistFile") { 
     plist.editSingleValueInPlistFile(dictString: "YourPlistName", sFieldName: "yourSelectedDate", sValue: sYourSelectedDate) 
     plist.editSingleValueInPlistFile(dictString: "YourPlistName", sFieldName: "yourSelectedDateTime", sValue: sYourSelectedDateTime) 

    } else { 
     print("Unable to get Plist") 
    } 
    print(sYourSelectedDate); 
    print(sYourSelectedDateTime); 

} 

Answer 4

Swift 4 versión:

Configuración

UIDatePicker:

let datePicker = UIDatePicker() 
    datePicker.datePickerMode = .date 
    dateTextField.inputView = datePicker 
    datePicker.addTarget(self, action: #selector(datePickerChanged(picker:)), for: .valueChanged) 

---

Función:

@objc func datePickerChanged(picker: UIDatePicker) { 
    print(picker.date) 
} 

---

Si te fijas, Swift 4 requiere @objc en la función de si se va a utilizar #selector()