Ios – Find sender’s tag with gesture recognizer and swift

iosswifttagsuigesturerecognizer

tl;dr : how should I set my tags so that they can be retrieved with the gesture recognizer ?

I'm setting a view in which the user can spawn multiple UIImageViews when he presses a button.
The image creation process is :

var siegeView: UIView!
var round1: UIImageView!
var setTag : Int!
var tagCounter = 0

 @IBAction func showContent(sender: AnyObject) {


    round1 = UIImageView(frame: CGRectMake(0, 0, 100, 100))

    round1.image = UIImage(named: nomDuRond.text)

    setTag = tagCounter
    tagCounter++
    self.rond1.tag = setTag

    var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
    label.center = CGPointMake(round1.frame.origin.x+50, round1.frame.origin.y+100)
    label.textAlignment = NSTextAlignment.Center
    label.text = nomDuRond.text

    siegeView = UIView(frame: CGRectMake(round1.frame.origin.x, round1.frame.origin.y, round1.frame.size.width, round1.frame.size.height))

    round1.userInteractionEnabled = true
    siegeView.addSubview(rond1)
    siegeView.addSubview(label)

    view.addSubview(siegeView)

    let recognizer = UIPanGestureRecognizer(target: self, action:Selector("handlePan:"))
    recognizer.delegate = ClassSiege()
    siegeView.addGestureRecognizer(recognizer)

Then the user can move the created images using the Gesture Recognizer's fonction "handlePan" below :

 func handlePan(recognizer:UIPanGestureRecognizer) {
    let translation = recognizer.translationInView(self.view)
    self.view.bringSubviewToFront(recognizer.view!)
    recognizer.view!.center = CGPoint(x:recognizer.view!.center.x + translation.x,
        y:recognizer.view!.center.y + translation.y)
    recognizer.setTranslation(CGPointZero, inView: self.view)

    var centerBoardX = BlackBoard.center.x
    var centerBoardY = BlackBoard.center.y
    var centerRondX = round1.superview?.center.x
    var centerRondY = round1.superview?.center.y
    var switchRang = premierRang

    DistanceCenterY.text = " \(centerRondY! - centerBoardY)"


    if centerRondY! - centerBoardY < 100 {
        switchRang.setOn(true, animated: true)

        println("dans switch if")
    } else {

        switchRang.setOn(false, animated: true)
        println("dans switch else")
    }

}

My goal, for now, is to be able to get the DistanceCenterY information, and the if operation to be active for each view the user is moving. But it's only working for the last view created.
My guess is that it can work if I specify the image's tag.
But I can't figure out how to retrieve the tag of the image that is currently being moved by the user.

I tried this solution here, but it's not the image's tag as it always returns 0 even if the tag is different.

So, my question is : how should I set my tags so that they can be retrieved with the gesture recognizer ?

I'm deeply stuck here, so any help would be greatly appreciated !
Thanks

Update 1 :
Thanks to Rdelmar, I've been able to move forward… but not too far !

I updated the way I create the image, and modified the Gesture Recognizer fonction to use the tag info to get the info of which image is selected.

The code is :

var siegeView: UIView!
var rond1: UIImageView!
var rond2: UIImageView!
var setTag : Int!
var tagCounter = 1
var tagInfo = 0

  func handlePan(recognizer:UIPanGestureRecognizer) {
    let translation = recognizer.translationInView(self.view)
    recognizer.view!.center = CGPoint(x:recognizer.view!.center.x + translation.x,
        y:recognizer.view!.center.y + translation.y)
    recognizer.setTranslation(CGPointZero, inView: self.view)


    var switchRang = premierRang
    //Here I'm getting the tag from the recognizer. 
    var tag = recognizer.view?.tag
    tagInfo = tag!


    var centerBoardX = BlackBoard.center.x
    var centerBoardY = BlackBoard.center.y
    //to get the coordinates of the image, i'm getting the info using the tag I got earlier. 
    var centerRondX = rond1.viewWithTag(tagInfo)!.center.x
    var centerRondY = rond1.viewWithTag(tagInfo)!.center.y

    DistanceCenterY.text = " \(centerRondY - centerBoardY)"


    if centerRondY - centerBoardY < 100 {
        switchRang.setOn(true, animated: true)

        println("dans switch if")
    } else {

        switchRang.setOn(false, animated: true)
        println("dans switch else")
    }

}

and the showcontent fonction updated :

@IBAction func showContent(sender: AnyObject) {


    rond1 = UIImageView(frame: CGRectMake(0, 0, 100, 100))

    rond1.image = UIImage(named: nomDuRond.text)

    setTag = tagCounter
    tagCounter++
    rond1.tag = setTag

    var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
    label.center = CGPointMake(rond1.frame.origin.x+50, rond1.frame.origin.y+100)
    label.textAlignment = NSTextAlignment.Center
    label.text = nomDuRond.text

    rond1.userInteractionEnabled = true
    view.addSubview(rond1)
    //the label subview was getting me some bugs, so for now I removed it. 
    //view.addSubview(label)

    let recognizer = UIPanGestureRecognizer(target: self, action:Selector("handlePan:"))
    recognizer.delegate = ClassSiege()
    rond1.addGestureRecognizer(recognizer)

The tag returned is correct when I move the image, but when I adding a second image and I'm moving the first one, I get a fatal error because a nil was returned for the line var centerRondY = rond1.viewWithTag(tagInfo)!.center.y

I'm still stuck because I can't find what's wrong. It's not clear to me how the recognizer is working. If you have some clues, it's still very very much appreciated. Thanks !

Best Answer

I think this code does what you want. I commented some stuff out, since I didn't know what it was, and I hard coded the image and text in the label. As I said in my comment, you don't need to use tags, since each recognizer knows its own view. I commented out the button stuff, but I do see the "if" and "else" log statements fire as I move the views up and down the screen,

class ViewController: UIViewController {

    @IBAction func showContent(sender: AnyObject) {

        var rond1 = UIImageView(frame: CGRectMake(0, 0, 100, 100))
        rond1.image = UIImage(named:"Lofoten.jpg")

        var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
        label.center = CGPointMake(rond1.frame.origin.x+50, rond1.frame.origin.y+100)
        label.textAlignment = NSTextAlignment.Center
        label.text = "Picture"
        label.textColor = UIColor.whiteColor()
        label.frame = CGRectMake(0, rond1.frame.size.height - 25, 100, 25)

        rond1.addSubview(label)
        rond1.userInteractionEnabled = true

        view.addSubview(rond1)
        let recognizer = UIPanGestureRecognizer(target: self, action:Selector("handlePan:"))
        rond1.addGestureRecognizer(recognizer)

    }

    func handlePan(recognizer:UIPanGestureRecognizer) {
        let iv = recognizer.view
        let translation = recognizer.translationInView(self.view)
        iv.center.x += translation.x
        iv.center.y += translation.y
        recognizer.setTranslation(CGPointZero, inView: self.view)
       // var switchRang = premierRang

        var centerBoardY = self.view.center.y
        var centerRondY = iv.center.y

        //DistanceCenterY.text = " \(centerRondY - centerBoardY)"

        if centerRondY - centerBoardY < 100 {
            //switchRang.setOn(true, animated: true)

            println("dans switch if")
        } else {

            //switchRang.setOn(false, animated: true)
            println("dans switch else")
        }

    }
}

TL;DR

The difference between the commands is that one provides you with a tag message while the other doesn't. An annotated tag has a message that can be displayed with git-show(1), while a tag without annotations is just a named pointer to a commit.

More About Lightweight Tags

According to the documentation: "To create a lightweight tag, don’t supply any of the -a, -s, or -m options, just provide a tag name". There are also some different options to write a message on annotated tags:

When you use git tag <tagname>, Git will create a tag at the current revision but will not prompt you for an annotation. It will be tagged without a message (this is a lightweight tag).
When you use git tag -a <tagname>, Git will prompt you for an annotation unless you have also used the -m flag to provide a message.
When you use git tag -a -m <msg> <tagname>, Git will tag the commit and annotate it with the provided message.
When you use git tag -m <msg> <tagname>, Git will behave as if you passed the -a flag for annotation and use the provided message.

Basically, it just amounts to whether you want the tag to have an annotation and some other information associated with it or not.

Best Answer

Related Solutions

Iphone – Gesture recognizer and button actions

Git – the difference between an annotated and unannotated tag

TL;DR

More About Lightweight Tags

Related Topic