How to fix pass date between 2 ViewControllers - ios

Question

I try to pass imageName string data from ViewController to ImageViewController
which also func sliderImageTapped is sending data to CPImageSlider class
// ViewController.swift
import UIKit
let _AUTO_SCROLL_ENABLED : Bool = false
class ViewController: UIViewController, CPSliderDelegate {
var imagesArray = [String]()
var passDataDelegate: PassImageName?
#IBOutlet weak var slider : CPImageSlider!
#IBOutlet weak var autoSwitch : UISwitch!
#IBOutlet weak var arrowSwitch : UISwitch!
#IBOutlet weak var indicatorSwitch : UISwitch!
#IBOutlet weak var sliderSwitch : UISwitch!
#IBOutlet weak var circularSwitch : UISwitch!
override func viewDidLoad() {
super.viewDidLoad()
imagesArray = ["wallpaper1.jpg","wallpaper2.jpg","wallpaper3.jpg","wallpaper4.jpg"]
slider.images = imagesArray
slider.delegate = self
let zoom : CGFloat = 0.8
autoSwitch.transform = CGAffineTransform(scaleX: zoom, y: zoom)
arrowSwitch.transform = CGAffineTransform(scaleX: zoom, y: zoom)
indicatorSwitch.transform = CGAffineTransform(scaleX: zoom, y: zoom)
sliderSwitch.transform = CGAffineTransform(scaleX: zoom, y: zoom)
circularSwitch.transform = CGAffineTransform(scaleX: zoom, y: zoom)
autoSwitch.isOn = slider.autoSrcollEnabled
arrowSwitch.isOn = slider.enableArrowIndicator
indicatorSwitch.isOn = slider.enablePageIndicator
sliderSwitch.isOn = slider.enableSwipe
circularSwitch.isOn = slider.allowCircular
}
func sliderImageTapped(slider: CPImageSlider, imageName: String, index: Int) {
passDataDelegate?.passData(clickedImageName: imageName)
guard let destinationVC = storyboard?.instantiateViewController(withIdentifier: "ImageViewController") as? ImageViewController else {
return
}
present(destinationVC, animated: true, completion: nil )
print("\(index)")
}
}
// ImageViewController.swift
import UIKit
protocol PassImageName {
func passData(clickedImageName:String)
}
class ImageViewController: UIViewController, PassImageName {
#IBOutlet weak var image: UIImageView!
var imageName:String?
func passData(clickedImageName: String) {
imageName = clickedImageName
}
override func viewDidLoad() {
super.viewDidLoad()
image.image = UIImage(named: imageName ?? "wallpaper1.jpg")
}
#IBAction func dismiss(_ sender: UIButton) {
dismiss(animated: true, completion: nil)
}
}

Answer 1

You must initialize passDataDelegate before call the delegate method.
func sliderImageTapped(slider: CPImageSlider, imageName: String, index: Int) {
guard let destinationVC = storyboard?.instantiateViewController(withIdentifier: "ImageViewController") as? ImageViewController else {
return
}
passDataDelegate = destinationVC
passDataDelegate?.passData(clickedImageName: imageName)
present(destinationVC, animated: true, completion: nil )
print("\(index)")
}

Answer 2

I don't understand the point of your delegate, is there something preventing you to just set the imageName after instantiating the ImageViewController ?
func sliderImageTapped(slider: CPImageSlider, imageName: String, index: Int) {
guard let destinationVC = storyboard?.instantiateViewController(withIdentifier: "ImageViewController") as? ImageViewController else {
return
}
destinationVC.imageName = imageName
present(destinationVC, animated: true, completion: nil )
print("\(index)")
}
And then just set your image inside it :
var imageName:String? {
didSet {
image.image = UIImage(named: imageName ?? "wallpaper1.jpg")
}
}