CODEWITHSUNDEEP
iosswiftuipangesturerecognizer
Samson Chris Hong
Samson Chris Hong

Reputation: 13

Pan gesture not working properly

So I am creating an app with a grid that will create a node when I tap. Now, I am currently using PanGesture to drag and drop the node to a different location in the grid. Right now, I want the node I am dragging to be bigger (so it's easier for the user to see) and then go back to its size when it is dropped. So I used the "panGesture.state == begin" to implement a animation that will enlarge the node. However, this animation only begins when the node starts moving not when as soon as I touch it. According to the Apple API,

A pan gesture recognizer enters the began state as soon as the 
**required amount of initial movement is achieved**

meaning my node won't be bigger until I start dragging my node.

Is there any way I can fix this?

Upvotes: 1

Views: 3433

Answers (2)

mehdi
mehdi

Reputation: 2983

In pan gesture the .began means begin to move not begin to touch. You have to override func touchesBegan(_ touches: Set, with event: UIEvent?) function to get actual touch.

Upvotes: 1

Dmytro Trofymenko
Dmytro Trofymenko

Reputation: 310

You can use long press and pan gesture recognizers simultaneously. See code sample.

class ViewController: UIViewController, UIGestureRecognizerDelegate {
   var dragView: UIView!

   override func viewDidLoad() {
      super.viewDidLoad()

      self.dragView = UIView(frame: CGRect(x: 100.0, y: 100, width: 50.0, height: 50.0))
      self.dragView.backgroundColor = UIColor.red

      let panRecognizer = UIPanGestureRecognizer(target: self, action: #selector(pan))
      panRecognizer.delegate = self
      self.dragView.addGestureRecognizer(panRecognizer)

      let pressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(press))
      pressRecognizer.minimumPressDuration = 0.0 // IMPORTANT
      pressRecognizer.delegate = self
      self.dragView.addGestureRecognizer(pressRecognizer)

      self.view.addSubview(self.dragView)
   }

   @objc
   func press(gestureRecognizer: UILongPressGestureRecognizer) {
      switch gestureRecognizer.state {
         case .began:
            UIView.animate(withDuration: 0.1, animations: {
               self.dragView.transform = CGAffineTransform(scaleX: 1.1, y: 1.1)
            })
         case .cancelled, .ended, .failed:
            UIView.animate(withDuration: 0.1, animations: {
               self.dragView.transform = CGAffineTransform.identity
            })
         default: break
      }
   }

   @objc
   func pan(gestureRecognizer: UIPanGestureRecognizer) {
      switch gestureRecognizer.state {
         case .changed:
            var center = self.dragView.center
            let translation = gestureRecognizer.translation(in: self.dragView)
            center.x += translation.x
            center.y += translation.y
            self.dragView.center = center
            gestureRecognizer.setTranslation(CGPoint.zero, in: self.dragView)
         default: break
      }
   }

   // MARK: UIGestureRecognizerDelegate
   @objc
   func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
                          shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
      return true // IMPORTANT
   }
}

Upvotes: 1

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