adding gesture recognizer to uiimage

Question

I have image slider .. i followed this tutorial to do it: Create a Horizontal Paging UIScrollView with UIPageControl Swift 4 XCode 9 and it's working perfectly..

now i want to add gesture recognizer on these images .. i tried to do it like this:

func createSlides() -> [banner] {

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(tapped))
    tapGesture.numberOfTapsRequired = 1
    tapGesture.numberOfTouchesRequired = 1

    let slide1:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
    slide1.img.image = UIImage(named: "bannerex")
    slide1.img.addGestureRecognizer(tapGesture)

    let slide2:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
    slide2.img.image = UIImage(named: "bannerex")
    slide2.img.addGestureRecognizer(tapGesture)

    let slide3:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
    slide3.img.image = UIImage(named: "bannerex")
    slide3.img.addGestureRecognizer(tapGesture)

    return [slide1, slide2, slide3]
}

@objc func tapped(_ sender: UITapGestureRecognizer){
    print("tapped")
    print(pageControl.currentPage)
}

but it's not working, nothing will happen.

How to solve this issue?

import UIKit

class banner: UIView {


@IBOutlet weak var img: UIImageView!

 }

Quick hint: as per Swift code convention, class names (in this case `banner`) should start with an uppercase letter :) — LinusGeffarth, Feb 21 '19 at 07:57
@LinusGeffarth thanks for that :) .. but this is has nothing to do with my problem right? — mrs.tat, Feb 21 '19 at 07:59
Nope, sure doesn't. Try setting `slide1.img.isUserInteractionEnabled = true` (and for the others also). — LinusGeffarth, Feb 21 '19 at 08:00
@LinusGeffarth i did .. and worked only for the last image view in the array .. how to apply it to all? — mrs.tat, Feb 21 '19 at 08:04
Can you show your implementation of `Banner`? I'm guessing, that'd be a better place to put it. — LinusGeffarth, Feb 21 '19 at 08:05
See my answer below. I figured, instead of giving a short-hand answer, I'd do a more elaborate one that helps you get up and running, plus, it suggests best-practices :) — LinusGeffarth, Feb 21 '19 at 08:12
@LinusGeffarth I really appreciate this! many thanks for the help. — mrs.tat, Feb 21 '19 at 08:17

score 3 · Accepted Answer · answered Feb 21 '19 at 08:10

There are two problems here:

isUserInteractionEnabled is false by default
you have to assign each image view a separate gesture recognizer

Solution

Instead of setting isUserInteractionEnabled to true for each image view individually, I suggest placing that code in the Banner class itself. Since it seems your initializing it from the storyboard, using the awakeFromNib function should work just fine:

class Banner: UIView {

    @IBOutlet weak var img: UIImageView!

    override func awakeFromNib() {
        super.awakeFromNib()
        img.isUserInteractionEnabled = true
    }
 }

In your createSlides() function, add a separate tap gesture to each view:

let slide1:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
slide1.img.image = UIImage(named: "bannerex")
slide1.img.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(tapped)))

or even better for scaling & no-code-redundancies:

function tap() -> UITapGestureRecognizer {
    return UITapGestureRecognizer(target: self, action: #selector(tapped))
}

let slide1:banner = Bundle.main.loadNibNamed("banner", owner: self, options: nil)?.first as! banner
slide1.img.image = UIImage(named: "bannerex")
slide1.img.addGestureRecognizer(tap())

score 2 · Answer 2 · answered Feb 21 '19 at 08:05

2

The UITapGestureRecognizer must be used with a single view only so you need to create different UITapGestureRecognizer for each image if you want to detect tap on each image. Read more HERE.

And you need to set isUserInteractionEnabled to true for every imageView.

answered Feb 21 '19 at 08:05

Dharmesh Kheni

71,228
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Happy to help.. :) – Dharmesh Kheni Feb 21 '19 at 08:08
Downvotes are welcomed but please mention a reason in comment. That way it will be helpful. – Dharmesh Kheni Feb 21 '19 at 08:17
no i won't downvote :) .. but can i accept @LinusGeffarth's answer since its the clearest answer? – mrs.tat Feb 21 '19 at 08:19

score 0 · Answer 3 · answered Feb 21 '19 at 08:00

0

Image views ignore user events by default. If you want an image view to handle user interactions as well, change the value of its isUserInteractionEnabled property to true.

answered Feb 21 '19 at 08:00

Rocky

2,903
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I just set that to true for all of the images in the array .. and worked only for the last image view in the list .. why? – mrs.tat Feb 21 '19 at 08:05

adding gesture recognizer to uiimage

3 Answers3

Solution