Swipe back and forth through array of images Swift

arrays, ios, swift, uiswipegesturerecognizer

Solution

First of all your image index should be set to zero since array elements starts from zero but thats not a source of your problem

var imageIndex: NSInteger = 0

then your swiped function should be like following

func swiped(gesture: UIGestureRecognizer) {

if let swipeGesture = gesture as? UISwipeGestureRecognizer {

    switch swipeGesture.direction {

    case UISwipeGestureRecognizerDirection.Right :
        println("User swiped right")

        // decrease index first

        imageIndex--

        // check if index is in range

        if imageIndex < 0 {

            imageIndex = maxImages

        }

       image.image = UIImage(named: imageList[imageIndex])

    case UISwipeGestureRecognizerDirection.Left:
        println("User swiped Left")

        // increase index first

        imageIndex++

        // check if index is in range

        if imageIndex > maxImages {

            imageIndex = 0

        }

       image.image = UIImage(named: imageList[imageIndex])




    default:
        break //stops the code/codes nothing.


    }

}


}

Problem

I have an array of images that I want to be able to swipe forward (left) to the next image, or back (right) to the previous image. When the imageList hits -1/out of range, the app crashes. I'm having trouble of figuring out the logic of how to keep it within range. Here is my code: ``` var imageList:[String] = ["image1.jpg", "image2.jpg", "image3.jpg"] let maxImages = 2 var imageIndex: NSInteger = 1 ``` The swipe gestures are in my viewDidLoad() method, not sure if this is the right place... : ``` override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view, typically from a nib. var swipeRight = UISwipeGestureRecognizer(target: self, action: "swiped:") // put : at the end of method name swipeRight.direction = UISwipeGestureRecognizerDirection.Right self.view.addGestureRecognizer(swipeRight) var swipeLeft = UISwipeGestureRecognizer(target: self, action: "swiped:") // put : at the end of method name swipeLeft.direction = UISwipeGestureRecognizerDirection.Left self.view.addGestureRecognizer(swipeLeft) image.image = UIImage(named:"image1.jpg") } func swiped(gesture: UIGestureRecognizer) { if let swipeGesture = gesture as? UISwipeGestureRecognizer { switch swipeGesture.direction { case UISwipeGestureRecognizerDirection.Right : println("User swiped right") /*No clue how to make it go back to the previous image and when it hits the last image in the array, it goes back to the first image.. */ case UISwipeGestureRecognizerDirection.Left: println("User swiped Left") if imageIndex > maxImages { imageIndex = 0 } image.image = UIImage(named: imageList[imageIndex]) imageIndex++ default: break //stops the code/codes nothing. } } } ``` Thanks a lot in advance!

Original source