Multiple picker views: unexpectedly found nil while unwrapping an Optional value - ios

Question

I'm trying to create a view controller with multiple pickerviews using the following code:
import UIKit
import Firebase
import FirebaseAuth
class DormViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
#IBOutlet weak var dormName: UIPickerView!
#IBOutlet weak var entryway: UIPickerView!
#IBOutlet weak var roomNumber: UIPickerView!
#IBOutlet weak var nextButton: UIButton!
var ref: DatabaseReference!
let dorms = ["Adams", "Apley", "Cabot", "Canaday", "Currier", "DeWolfe 10", "Dewolfe 20", "Dunster", "Eliot", "Fairfax", "Grays", "Greenough", "Hollis", "Holworthy", "Hurlbut", "Inn at Harvard", "Kirkland", "Leverett Towers", "Leverett McKinlock Hall", "Lionel", "Lowell", "Massachusetts Hall", "Mather Lowrise", "Mather Tower", "Matthews", "Mower", "New Quincy", "Pennypacker", "Pforzheimer", "Pforzheimer Jordan North", "Pforzheimer Jordan South", "Stone Hall", "Stoughton", "Straus", "Thayer", "Weld", "Wigglesworth", "Winthrop" ]
let entrances = ["N/A", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]
let rooms = ["N/A", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "70", "71", "72", "73", "74", "75", "76", "77", "78", "79", "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "90", "91", "92", "93", "94", "95", "96", "97", "98", "99"]
override func viewDidLoad() {
super.viewDidLoad()
ref = Database.database().reference()
dormName = UIPickerView()
entryway = UIPickerView()
roomNumber = UIPickerView()
dormName.delegate = self
dormName.dataSource = self
entryway.delegate = self
entryway.dataSource = self
roomNumber.delegate = self
roomNumber.dataSource = self
dormName.tag = 0
entryway.tag = 1
roomNumber.tag = 2
// Do any additional setup after loading the view.
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if pickerView.tag == 1 {
return dorms[row]
}
else if pickerView.tag == 2 {
return entrances[row]
}
else {
return rooms[row]
}
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if pickerView.tag == 1 {
return dorms.count
}
else if pickerView.tag == 2 {
return entrances.count
}
else {
return rooms.count
}
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let user = Auth.auth().currentUser
if let user = user {
let uid = user.uid
var entry = entrances[row]
var num = rooms[row]
if entrances[row] == "N/A" {
entry = ""
}
if rooms[row] == "N/A" {
num = ""
}
self.ref.child("Dorms").child(uid).setValue(["Location": dorms[row] + " " + entry + "-" + num ])
}
else {
print("error")
}
}
#IBAction func nextButton(_ sender: Any) {
performSegue(withIdentifier: "tohomepage", sender: self)
}
}
However, I'm getting an error:
fatal error: unexpectedly found nil while unwrapping an Optional value
In my viewDidLoad() function, when I make the call:
dormName.delegate = self
I've tried deleting the delegate and dataSource calls, and the same error still happens. I also tried deleting the tags and referencing the picker views by their names, as in:
pickerview == "dormName"
But then I get an index out of range error.
What am I doing wrong?

Answer 1

when you drag UIPickerView from xib or storyboad you don't need call some init :
dormName = UIPickerView()
entryway = UIPickerView()
roomNumber = UIPickerView()
delete it , and try again

Answer 2

In your didSelectRow you do not check for the picker instance anymore and just access the data of all arrays by the same row index. This will cause an index out of range error as soon as you pick an item with an index that goes beyond the smallest array length (in this case, entrances).
Also, looks like you have your tags/indices wrong. E.g. you set the tag of dormName to 0, but in your code you access the dorm data when the tag equals 1 (which in fact refers to the entryway picker).