CODEWITHSUNDEEP
iosiphoneswiftuiimageviewdraggable
SagittariusA
SagittariusA

Reputation: 5427

Swift: which methods are needed to implement a draggable UIImageView?

As said in title, I would like the user to be able to drag a UIImageView which serves as pin on a picture and I have followed this tutorial. Here's the class I have written:

import UIKit

class PinImageView: UIImageView {

var lastLocation:CGPoint?
var panRecognizer:UIPanGestureRecognizer?

init(imageIcon: UIImage?, location:CGPoint) {
    super.init(image: imageIcon)
    self.lastLocation = location
    self.panRecognizer = UIPanGestureRecognizer(target:self, action:"detectPan:")
    self.center = location
    self.gestureRecognizers = [panRecognizer!]
    self.frame = CGRect(x: location.x, y: location.y, width: 20.0, height: 30.0)
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

func detectPan(recognizer:UIPanGestureRecognizer) {
    let translation  = recognizer.translationInView(self.superview!)
    self.center = CGPointMake(lastLocation!.x + translation.x, lastLocation!.y + translation.y)
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    // Promote the touched view
    self.superview?.bringSubviewToFront(self)

    // Remember original location
    lastLocation = self.center
}

}

Those pin UIImageViews should move upon a larger UIImageView which is contained UIViewController where:

class PhotoViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

@IBOutlet weak var imageView: UIImageView!
var imagePicker: UIImagePickerController!
var redLocationA:PinImageView = PinImageView(imageIcon: UIImage(named: "pin1.png"), location: CGPointMake(80, 330))
var redLocationB:PinImageView = PinImageView(imageIcon: UIImage(named: "pin1.png"), location: CGPointMake(80, 360))

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.addSubview(redLocationA)
    self.view.addSubview(redLocationB)
}

...
}

When I launch the app everything is correctly showed but the pins do not move if I try to drag them. I am afraid I am missing something...do you know what? Maybe the method touchedìsMoved() but it's not mentioned in the tutorial...

Upvotes: 4

Views: 1826

Answers (1)

SagittariusA
SagittariusA

Reputation: 5427

UPDATE: answer

Stupid me, I missed 

self.userInteractionEnabled = true

inside the init() method, I thought they were enabled by default.

Upvotes: 3

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