CODEWITHSUNDEEP
iosswiftgestures
Benny
Benny

Reputation: 755

iOS Swift, cannot get pinch gesture to work

i have a test project that takes text from a file, adds it to a textview and displays it. i want to add some gestures but cannot seem to make it work... here is the relevant code:

class ViewController2: UIViewController, UIGestureRecognizerDelegate {

@IBOutlet var textview1: UITextView!

var pinchGesture = UIPinchGestureRecognizer()

override func viewDidLoad() {
    super.viewDidLoad()

    self.textview1.userInteractionEnabled = true
    self.textview1.multipleTouchEnabled = true

    self.pinchGesture.delegate = self
    self.pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(ViewController2.pinchRecognized(_:)))
    self.view.addGestureRecognizer(self.pinchGesture)
}


@IBAction func pinchRecognized(pinch: UIPinchGestureRecognizer) {
    self.textview1.addGestureRecognizer(pinchGesture)
    self.textview1.transform = CGAffineTransformScale(self.textview1.transform, pinch.scale, pinch.scale)
    pinch.scale = 1.0
}

any ideas? followed several tutorials but none seem to help. code is tested on actual iPhone...

thanks a lot

Edit for Solution:

@IBAction func pinchRecognized(pinch: UIPinchGestureRecognizer) {
    var pinchScale = pinchGesture.scale
    pinchScale = round(pinchScale * 1000) / 1000.0
    if (pinchScale < 1) {
        self.textview1.font = UIFont(name: self.textview1.font!.fontName, size: self.textview1.font!.pointSize - pinchScale)
        pinchScale = pinchGesture.scale
    } else {
        self.textview1.font = UIFont(name: self.textview1.font!.fontName, size: self.textview1.font!.pointSize + pinchScale)
        pinchScale = pinchGesture.scale
    }
}

thanks to nishith Singh

Upvotes: 5

Views: 12103

Answers (5)

nishith Singh
nishith Singh

Reputation: 2988

Try adding the gesture recogniser to your textview in viewDidLoad instead of adding it in pinchRecognized. Currently you are adding the pinchGesture to your view which is behind your text view and hence will not receive the touch

var pinchGesture = UIPinchGestureRecognizer()

Use this code:

override func viewDidLoad() {
    super.viewDidLoad()
    
    self.textview1.userInteractionEnabled = true
    self.textview1.multipleTouchEnabled = true
    
    self.pinchGesture = UIPinchGestureRecognizer(target: self, action:#selector(pinchRecognized(_:)))
    self.textview1.addGestureRecognizer(self.pinchGesture)

    // Do any additional setup after loading the view.
}

@IBAction func pinchRecognized(_ pinch: UIPinchGestureRecognizer) {
    let fontSize = self.textview1.font!.pointSize*(pinch.scale)/2
    if fontSize > 12 && fontSize < 32{
        textview1.font = UIFont(name: self.textview1.font!.fontName, size:fontSize)
    }
}

You might have to hit and trial with the minimum and maximum font sizes as you want, right now the minimum font size is 12 and the maximum font size is 32.

Upvotes: 8

pkc456
pkc456

Reputation: 8506

You set the delegate of self.pinchGesture before initialising.

  • Initialise the self.pinchGesture first.
  • Set the delegate.

  • Add self.pinchGesture to self.view

    self.pinchGesture.delegate = self
self.pinchGesture = UIPinchGestureRecognizer(target: self, action:#selector(ViewController2.pinchRecognized(_:)))
self.view.addGestureRecognizer(self.pinchGesture)

Upvotes: 0

Sai kumar Reddy
Sai kumar Reddy

Reputation: 1829

let pinchGesture = UIPinchGestureRecognizer(target: self, action:#selector(self.pinchGesture))
func pinchGesture(sender: UIPinchGestureRecognizer){
sender.view?.transform = (sender.view?.transform)!.scaledBy(x:   sender.scale, y: sender.scale)
    sender.scale = 1
    print("pinch gesture")
}

Upvotes: 2

Prajeet Shrestha
Prajeet Shrestha

Reputation: 8108

Your code is actually working. But not the way you want probably.

Initially you assigned the gesture recogniser to the view of view controller.

But then inside the method you added same gesture recogniser to the UITextView.

So it should be working on UITextView. And the gesture recogniser is removed from the view controller's view. Gesture recogniser can only have one target. Pick view controller's view or textview.

Upvotes: 0

Jayesh Miruliya
Jayesh Miruliya

Reputation: 3317

class ViewController2: UIViewController, UIGestureRecognizerDelegate {

@IBOutlet var textview1: UITextView!

var pinchGesture = UIPinchGestureRecognizer()

override func viewDidLoad() {
    super.viewDidLoad()

    self.textview1.userInteractionEnabled = true
    self.textview1.multipleTouchEnabled = true

    self.pinchGesture.delegate = self
    self.pinchGesture = UIPinchGestureRecognizer(target: self, action: "pinchRecognized:")
    self.view.addGestureRecognizer(self.pinchGesture)
}


func pinchRecognized(pinch: UIPinchGestureRecognizer) {
    self.textview1.addGestureRecognizer(pinchGesture)
    self.textview1.transform = CGAffineTransformScale(self.textview1.transform, pinch.scale, pinch.scale)
    pinch.scale = 1.0
}

Upvotes: 0

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