Swift 4- App crashes on button press that starts segue - ios

Question

I am programming an application and it is supposed to go to another view controller on a button press but instead it crashes when I run it. The editor shows this: and with editor breakpointing on it shows this: but there is no error in the console. Here is the code for the viewcontroller that does the segue:
//
// DoTodayViewController.swift
// Paley Foundation: Starfish Support
//
// Created by Sa'ar Lipshitz on 10/28/17.
//
import UIKit
class DoTodayViewController: UIViewController {
#IBOutlet weak var navItem: UINavigationItem!
#IBOutlet weak var getBtn: UIButton!
#IBOutlet weak var suggestBtn: UIButton!
var name = "Sa'ar"
override func viewDidLoad() {
super.viewDidLoad()
getBtn.layer.cornerRadius = 8
getBtn.clipsToBounds = true
suggestBtn.layer.cornerRadius = 8
suggestBtn.clipsToBounds = true
navItem.prompt = "What would you like to do today, "+name+"?"
}
#IBAction func suggest(_ sender: Any) {
let vc = storyboard?.instantiateViewController(withIdentifier: "SuggestViewController") as! SuggestViewController
navigationController?.pushViewController(vc, animated: true)
}
//This crashes my app:
#IBAction func get(_ sender: Any) {
let vc = storyboard?.instantiateViewController(withIdentifier: "AccessViewController") as! AccessViewController
navigationController?.pushViewController(vc, animated: true)
}
}
and here is my code for the viewcontroller that gets opened:
//
// AccessViewController.swift
// Paley Foundation: Starfish Support
//
// Created by Sa'ar Lipshitz on 10/29/17.
//
import UIKit
import Firebase
import Material
class AccessViewController: UIViewController {
var adviceRef: DatabaseReference!
var advice: [[String: Any]] = []
var i = 0
var card: Card!
var loadingLbl: UILabel!
var panGesture = UIPanGestureRecognizer()
var cardOrigPos: CGPoint!
override func viewDidLoad() {
super.viewDidLoad()
adviceRef = Database.database().reference().child("Advice")
var advDict: NSDictionary?
adviceRef.observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
advDict = value
print(advDict as Any)
for (_, adv) in advDict! {
self.advice.append(adv as! [String : Any])
}
print(self.advice)
self.showNextCard()
}) { (error) in
print(error.localizedDescription)
}
let swipeRec = UIPanGestureRecognizer(target: self, action: #selector(swipe(sender:)))
card.isUserInteractionEnabled = true
card.addGestureRecognizer(swipeRec)
}
#objc func swipe(sender: UIPanGestureRecognizer) {
let translation = sender.translation(in: view)
let velocity = sender.velocity(in: view)
let direction = velocity
print("Translation: \(translation)")
if sender.state == .began {
cardOrigPos = card.center
} else if sender.state == .changed {
card.center = CGPoint(x: cardOrigPos.x+translation.x, y: cardOrigPos.y+translation.y)
} else if sender.state == .ended {
if velocity.y == 0 && velocity.x == 0 {
UIView.animate(withDuration: 0.3, animations: {
self.card.center = self.view.center
})
} else {
UIView.animate(withDuration: 0.3, animations: {
self.card.center = CGPoint(x: self.cardOrigPos.x+direction.x*5, y: self.cardOrigPos.y+direction.y)
})
self.showNextCard()
}
}
}
func showNextCard() {
if advice.count >= 0 {
let adv = advice[i]
setCard(adv["username"] as? String, adv["title"] as! String, adv["desc"] as! String, image: adv["image"] as? UIImage)
i += 1
if i >= advice.count {
i = 0
}
}
}
func setCard(_ username: String?, _ title: String, _ desc: String, image: UIImage?) {
let toolbar = setToolbar(username ?? "", title)
card = Card()
card.toolbar = toolbar
card.toolbarEdgeInsetsPreset = .square3
card.toolbarEdgeInsets.bottom = 0
card.toolbarEdgeInsets.right = 8
card.contentView = setContentView(content: desc)
card.contentViewEdgeInsetsPreset = .wideRectangle3
card.layer.borderWidth = 1.0
card.layer.borderColor = UIColor.black.cgColor
card.layer.cornerRadius = 2
view.layout(card).horizontally(left: 20, right: 20).center()
}
func setToolbar(_ username: String, _ title: String) -> Toolbar {
let toolbar = Toolbar(rightViews: [setMoreBtn()])
toolbar.title = title
toolbar.detail = username
toolbar.detailLabel.textColor = Color.grey.base
return toolbar
}
func setMoreBtn() -> IconButton {
let moreBtn = IconButton(image: Icon.cm.moreVertical, tintColor: Color.grey.base)
return moreBtn
}
func setContentView(content: String) -> UILabel {
let contentView = UILabel()
contentView.numberOfLines = 0
contentView.text = content
contentView.font = RobotoFont.regular(with: 14)
return contentView
}
}
When I tried using print statements to debug, the one in the DoTodayViewController.get(_ sender: Any) method ran but not the one in AccessViewController.viewDidLoad()

Answer 1

Make sure you changed the class of the view controller object in the storyboard to AccessViewController and that the Storyboard ID is correctly spelled. You may be encountering a nil when trying to force unwrap storyboard?.instantiateViewController(withIdentifier: "AccessViewController") as! AccessViewController. Try using if let wherever an optional needs to be unwrapped to handle the scenario of it being nil.