Class 'ProductDetailViewController' has no initializers - ios

Question

I am trying to create scrollable imageview. Currently using swift 4.0. While running I am getting "has no initializers" error. I am not sure what code brought this error. I am new to swift and I am unable to track what is going on.
Class 'ProductDetailViewController' has no initializers I am getting this error.
Can any one please tell me how to fix this error.
Entire view controller code is given below. Thanks in advance
import UIKit
import SwiftyJSON
class ProductDetailViewController: UIViewController,UIScrollViewDelegate {
//Outlers
#IBOutlet weak var scrollView: UIScrollView!
//Global variables
var productDict : JSON = []
var arrayOfProductImageUrls : Array<Any> = []
var zoomScroll : UIScrollView
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.initialSetup()
self.scrollViewSetup()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
//Mark: - Scrollview Setup
func initialSetup() {
self.scrollView.delegate = self
}
func scrollViewSetup() {
let productsArray : Array = self.arrayOfProductImageUrls;
self.scrollView.backgroundColor = UIColor.white
var frame : CGRect = CGRectMake(0, 0, self.scrollView.frame.size.width, 360)
for (index, value) in productsArray.enumerated() {
//Imageview Setup
let productImageView : UIImageView
let width : NSInteger = Int(frame.width)
productImageView.frame.origin.x = CGFloat(Int (width * index))
productImageView.frame.origin.y = 0
//Scrollview Setup
zoomScroll.frame = frame;
zoomScroll.backgroundColor = UIColor.clear
zoomScroll.showsVerticalScrollIndicator = false
zoomScroll.showsHorizontalScrollIndicator = false
zoomScroll.delegate = self
zoomScroll.minimumZoomScale = 1.0
zoomScroll.maximumZoomScale = 6.0
zoomScroll.tag = index
zoomScroll.isScrollEnabled = true
self.scrollView.addSubview(zoomScroll)
//Setting image
let imageUrl : URL = (productsArray[index] as AnyObject).url
productImageView.sd_setImage(with: imageUrl)
if index < productsArray.count {
productImageView.frame = zoomScroll.bounds
productImageView.contentMode = UIViewContentMode.redraw
productImageView.clipsToBounds = true
productImageView.backgroundColor = UIColor.clear
zoomScroll.addSubview(productImageView)
}
self.scrollView.contentSize = CGSizeMake(CGFloat(frame.origin.x) + CGFloat(width), productImageView.frame.size.height)
}
}
//Mark : Custom methods
func CGRectMake(_ x: CGFloat, _ y: CGFloat, _ width: CGFloat, _ height: CGFloat) -> CGRect {
return CGRect(x: x, y: y, width: width, height: height)
}
func CGSizeMake(_ width: CGFloat, _ height: CGFloat) -> CGSize {
return CGSize(width: width, height: height)
}
}

Answer 1

#Saurabh Prajapati. Nice and quick catch.
For more, The Swift Programming Language states
Classes and structures must set all of their stored properties to an
appropriate initial value by the time an instance of that class or
structure is created. Stored properties cannot be left in an
indeterminate state.
You can set an initial value for a stored property within an
initializer, or by assigning a default property value as part of the
property’s definition.
Let me explain more, the problem was with scrollView property that does not have a default value. As above mentioned, all variables in Swift must always have a value or nil (make it optional). When you make it optional, you allow it to be nil by default, removing the need to explicitly give it a value or initialize it.
Here we are using ! optional so the default value will be nil
class ViewController : UIViewController {
#IBOutlet weak var scrollView: UIScrollView!
}
Setting nil as the default value
class ViewController : UIViewController {
#IBOutlet weak var scrollView: UIScrollView! = nil
}
Setting the default value, creating an object now it is not nil.
class ViewController : UIViewController {
#IBOutlet weak var scrollView: UIScrollView = UIScrollView()
}
But we can't-do like that, we are not setting the default value here.
class ViewController : UIViewController {
#IBOutlet weak var scrollView: UIScrollView
}
I hope it will help.

Answer 2

I had the same echo
it was so easy to solve it by using ! after any variable like this
var ref: DatabaseReference!