Zoom not working in scroll view

Question

I have a scrollview in swift 3. The zoom is not working. I have set up the scrollview and put an imageview inside. I have set self as the delegate and implemented viewForZoomingInScrollView. please take a look. thanks.

edit: another thing I didn't mention before was that this is view in a navigation controller. would that affect it?

class FlowDiagramViewController: UIViewController, UIScrollViewDelegate {

    var scrollView: UIScrollView!
    var imageView:UIImageView! = UIImageView()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        let image = UIImage(named: "flowNewRotated1242x2208.png")
        imageView = UIImageView(image: image)

        setupPictureWithZoom()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func setupPictureWithZoom() {
        // http://stackoverflow.com/questions/30014241/uiimageview-pinch-zoom-swift

        imageView.frame = CGRect(x: 0, y: 0, width: 1242, height: 2208)
        // imageView.transform = imageView.transform.rotated(by: CGFloat(M_PI_2))
        imageView!.layer.cornerRadius = 11.0
        imageView!.clipsToBounds = false

        scrollView = UIScrollView(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height))


        scrollView.minimumZoomScale = 0.25
        scrollView.maximumZoomScale = 5.0

        scrollView.delegate = self

        scrollView.backgroundColor = UIColor(red: 90, green: 90, blue: 90, alpha: 0.90)
        scrollView.alwaysBounceVertical = false
        scrollView.alwaysBounceHorizontal = false
        scrollView.showsVerticalScrollIndicator = true
        scrollView.flashScrollIndicators()
        scrollView.contentSize = CGSize(width: 1242, height: 2208)


        scrollView.addSubview(imageView!)
        view.addSubview(scrollView!)


        scrollView.setZoomScale(0.25, animated: true)
    }

    func viewForZoomingInScrollView(scrollView: UIScrollView!) -> UIView! {
        return imageView
    }
}

I have tried both defining the scrollview in the storyboard and in code.

score 7 · Accepted Answer · edited Apr 03 '18 at 14:57

7

It was a swift 3 issue.

New function prototype is as below :

Swift 3 version

func viewForZooming(in scrollView: UIScrollView) -> UIView? {
    return imageView
}

Swift 2 version

//    func viewForZoomingInScrollView(scrollView: UIScrollView!) -> UIView! {
//        return imageView
//    }

edited Apr 03 '18 at 14:57

Hasya

9,792
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answered Mar 03 '17 at 05:34

mjpablo23

681
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7
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Common issue when moving code and hard to find. Upvote this! – Jon Thomason Jul 18 '17 at 21:35

score 2 · Answer 2 · answered Mar 03 '17 at 01:35

2

These 2 lines must be in the viewDidLoad:

scrollView.minimumZoomScale = 0.25 
scrollView.maximumZoomScale = 5.0

answered Mar 03 '17 at 01:35

Shiva Devarajan

53
5

score 0 · Answer 3 · answered Mar 03 '17 at 04:05

0

Try changing the content sizer like below it works like a charm

scrollView.contentSize = imageView.frame.size

answered Mar 03 '17 at 04:05

Vinodh

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Zoom not working in scroll view

3 Answers3