My Question is about changing a UIImage when a button is pressed - ios

Question

So I am quite new to coding, learning Swift 3 on Udemy. I'm trying to test my skills by building a music app that contains 3 sound files, at the moment I am struggling to get the image of the current song that should be playing once my UIButton is pressed. I have created an array containing the image files but for some reason it only shows 2 out of the 3 images and will not go further nor will it let me loop the images, any and all suggestions are welcome.
I have tried a for-in loop which is not what I want at the moment. I am trying to get the function to update songImage to accept my array and link to the sender.tag property to cycle through the images
class ViewController: UIViewController {
// Instance Variables
var playTheSong : AVAudioPlayer!
var imageArray = ["songImage1", "songImage2", "songImage3"]
var allSongNamesAndDescriptions = MusicClassBank()
var nextImage = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
albumArtwork.image = UIImage(named: "songImage3")
}
#IBAction func buttonPressed(_ sender: UIButton) {
updateSongImage(selectedImageFile: imageArray[sender.tag - 1])
nextImage = nextImage + 1
}
#IBOutlet weak var albumArtwork: UIImageView!
#IBOutlet weak var nameOfSong: UILabel!
#IBOutlet weak var songDescription: UILabel!
// Cycle through images upon button being pressed.
func updateSongImage(selectedImageFile : String) {
if nextImage <= 3 {
albumArtwork.image = UIImage(named: selectedImageFile)
}
else {
nextImage = 0
}
}
Right now the code is showing just the image displayed upon view load and the next image in the array. I cannot get it to go through the entire array and keep going when the button is pressed.

Answer 1

You are using the "next" UIButton sender.tag as a parameter to change the image, but that tag never changes. So:
In your viewDidLoad() method, you show the third image
When you press the "next" button, you update the image to 1 (probably the sender.tag is 1)
Pressing the button again don't update the image
You can try something like this:
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
//Set the first image
updateSongImage(selectedImageFile : imageArray[0])
}
#IBAction func buttonPressed(_ sender: UIButton) {
//If nextImage is less than imageArray.count - 1 (because arrays start with 0), add one to nextImage. Else, nextImage return to zero
nextImage = nextImage < imageArray.count - 1 ? nextImage + 1 : 0
updateSongImage(selectedImageFile: imageArray[nextImage])
}
func updateSongImage(selectedImageFile : String) {
//Here we only need to update the image, because the if is outside
albumArtwork.image = UIImage(named: selectedImageFile)
}