Passing Information from ViewController to ViewController using Swift

Question

I'm new to coding and Swift. For my first attempt at an app, I'm attempting to make a mobile music reminder application, in which I can type in the Artist, Album and Release Date and it'll notify me on the release date that the album came out today.

I'm working on the edit button, where if I misspelled the Artist or Album or even got the Release Date wrong, I could go in and edit the already saved information and have that new data saved over the original.

Currently, I'm trying to pass information from one ViewController to another ViewController but I'm having some difficulties.

I need the Artist, Album and Release Date information from the AddfreshreleaseViewController to go the EditfreshreleaseViewController

So far I've only attempted to get the Artist information to pass but I haven't had any luck. I've watched videos and read numerous articles and books but I can't seem to get it to work.

Below is the AddfreshreleaseViewController code:

 import UIKit
 import CoreData
 import UserNotifications

 class AddfreshreleaseViewController: UIViewController {

@IBOutlet weak var Artist: UITextField!


/* @IBOutlet weak var textfield = UITextField? (artisttextfield!)



let EditfreshreleaseViewController =  segue.destination as! EditfreshreleaseViewController

EditfreshreleaseViewController.receivedString = artisttextfield.text!

}

override func prepare (for segue: UIStoryboardSegue, sender: Any?) {*/


@IBOutlet var artisttextfield: UITextField!
@IBOutlet var albumtextfield: UITextField!
@IBOutlet var releasedatePicker: UIDatePicker!

override func viewDidLoad() {
    super.viewDidLoad()

    releasedatePicker.minimumDate = Date()

    func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?){
        var destinationAddfreshreleaseViewController : EditfreshreleaseViewController = segue.destinationAddfreshreleaseViewController as EditfreshreleaseViewController

        destinationAddfreshreleaseViewController.ArtistText = Artist.text!

    }

    // Do any additional setup after loading the view, typically from a nib.
}
@IBAction func saveTapped( _ sender: UIBarButtonItem) {

    let artist = artisttextfield.text ?? ""
    let album = albumtextfield.text ?? ""
    let releasedate = releasedatePicker.date

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let newRelease = Release_Date(context: context)
    newRelease.artist = artist
    newRelease.album = album
    newRelease.release_date = releasedate as NSDate?
    newRelease.release_dateId = UUID().uuidString

    if let uniqueId = newRelease.release_dateId {
        print("The freshreleaseId is \(uniqueId)")
    }

    do {
        try context.save()
        let message = "\(artist)'s new album \(album) releases Today!"
        let content = UNMutableNotificationContent()
        content.body = message
        content.sound = UNNotificationSound.default()
        var dateComponents = Calendar.current.dateComponents([.month, .day],
            from: releasedate)
        dateComponents.hour = 09
        dateComponents.minute = 00
        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents,
            repeats: true)
        if let identifier = newRelease.release_dateId {

            let request = UNNotificationRequest(identifier: identifier,
                content: content, trigger: trigger)
            let center = UNUserNotificationCenter.current()
            center.add(request, withCompletionHandler: nil)
        }
    } catch let error {
        print("Could not save because of \(error).")
    }

    dismiss(animated: true, completion: nil)

    print("Added a Release Date!")
    print("Artist: \(newRelease.artist)")
    print("Album: \(newRelease.album)")
    print("Release Date: \(newRelease.release_date)")
}

@IBAction func cancelTapped(_ sender: UIBarButtonItem) {
    dismiss(animated: true, completion: nil)
}



}

Below is the EditfreshreleaseViewController code:

 import UIKit
 import CoreData
 import UserNotifications

 class EditfreshreleaseViewController: UIViewController {

@IBOutlet var Artist: UITextField!

var ArtistText = String()

@IBOutlet var artisttextfield: UITextField!
@IBOutlet var albumtextfield: UITextField!
@IBOutlet var releasedatePicker: UIDatePicker!
/*@IBOutlet weak var artist: UILabel! (ArtistTextField!)
    var receivedString = ""*/


override func viewDidLoad() {

    Artist.text = ArtistText

    super.viewDidLoad()

    /*artist.text = receivedString*/

    releasedatePicker.minimumDate = Date()

    // Do any additional setup after loading the view, typically from a nib.
}
@IBAction func saveTapped( _ sender: UIBarButtonItem) {

    let artist = artisttextfield.text ?? ""
    let album = albumtextfield.text ?? ""
    let releasedate = releasedatePicker.date

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let newRelease = Release_Date(context: context)
    newRelease.artist = artist
    newRelease.album = album
    newRelease.release_date = releasedate as NSDate?
    newRelease.release_dateId = UUID().uuidString

    if let uniqueId = newRelease.release_dateId {
        print("The freshreleaseId is \(uniqueId)")
    }

    do {
        try context.save()
        let message = "\(artist)'s new album \(album) releases Today!"
        let content = UNMutableNotificationContent()
        content.body = message
        content.sound = UNNotificationSound.default()
        var dateComponents = Calendar.current.dateComponents([.month, .day],
                                                             from: releasedate)
        dateComponents.hour = 09
        dateComponents.minute = 00
        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents,
                                                    repeats: true)
        if let identifier = newRelease.release_dateId {

            let request = UNNotificationRequest(identifier: identifier,
                                                content: content, trigger: trigger)
            let center = UNUserNotificationCenter.current()
            center.add(request, withCompletionHandler: nil)
        }
    } catch let error {
        print("Could not save because of \(error).")
    }

    dismiss(animated: true, completion: nil)

    print("Added a Release Date!")
    print("Artist: \(newRelease.artist)")
    print("Album: \(newRelease.album)")
    print("Release Date: \(newRelease.release_date)")
}

@IBAction func cancelTapped(_ sender: UIBarButtonItem) {
    dismiss(animated: true, completion: nil)
}



 }

Any help would be greatly appreciated.

Answer 1

The prepareForSegue function is a UIViewController method that must be overriden by subclasses, in order to pass data between other ViewControllers through a segue.

Try editing your code in AddfreshreleaseViewController to the following. (I've basically removed some code from your viewDidLoad function and added a new one just below it)

override func viewDidLoad() {
    super.viewDidLoad()

    releasedatePicker.minimumDate = Date()
}

override func prepareForSegue(for segue: UIStoryboardSegue, sender: Any?) {
    if let destination = segue.destination as? EditfreshreleaseViewController{
        destination.ArtistText = Artist.text!
    }
}