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!
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.
}
}
}