Call iOS pan and pinch recognizer from another class - ios

I am developing a SpriteKit application in iOS using Swift, and I have implemented pan and pinch gestures for my map. The code looks like this:
//Zoom recognizer
let pinch: UIPinchGestureRecognizer = UIPinchGestureRecognizer(target: self, action: Selector("pinch:"))
view.addGestureRecognizer(pinch)
// Move recognizer
let pan: UIPanGestureRecognizer = UIPanGestureRecognizer(target: self, action: Selector("pan:"))
view.addGestureRecognizer(pan)
func pinch(sender: UIPinchGestureRecognizer){
var anchorPoint: CGPoint = sender.locationInView(sender.view)
anchorPoint = convertPointFromView(anchorPoint)
if (sender.state == UIGestureRecognizerState.Changed) {
let anchorPointInMySKNode: CGPoint = world!.convertPoint(anchorPoint, fromNode: self)
world!.setScale(world!.xScale * sender.scale)
let mySKNodeAnchorPointInScene: CGPoint = self.convertPoint(anchorPointInMySKNode, fromNode: world!)
let translationOfAnchorInScene = CGPointSubtract(anchorPoint, point2: mySKNodeAnchorPointInScene)
world!.position = CGPointAdd(world!.position, point2: translationOfAnchorInScene)
sender.scale = 1.0
}
}
func pan(sender: UIPanGestureRecognizer){
if(sender.state == UIGestureRecognizerState.Began){
sender.setTranslation(CGPointZero, inView: sender.view)
}
else if (sender.state == UIGestureRecognizerState.Changed){
var translation: CGPoint = sender.translationInView(sender.view!)
translation = CGPointMake(-translation.x, translation.y)
world!.position = CGPointSubtract(world!.position, point2: translation)
sender.setTranslation(CGPointZero, inView: sender.view)
}
}
The code works fine but currently it is written in GameScene.swift class, however it would be better if could create a separate class called Gestures.swift and just call which ever gesture I want. I have tried several approaches but none of them work. The two main issues are how to address the selector in the GestureRecognizer function and how to pass the parent node which is in my case world initialized inside GameScene.swift

You need to use delegation. I have used something of this nature in my games (but in obj-c). Delegation is the way to go.
Here are a few resources I would recommend.
https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Protocols.html
http://code.tutsplus.com/tutorials/swift-from-scratch-delegation-and-properties--cms-23445
https://www.youtube.com/watch?v=AHx4nE7EMic
http://swift.exomachina.com/swift-tutorial-8-from-one-scene-to-another-using-delegate-protocol/

Related

Swift: Detect swiping across SCNNode

Is there any way to detect when the user swipe across SCNNode?
I ve already tried UISwipeGestureReconizer but it didn't work for me. Any ideas?
Try adding a pan gesture recognizer
let panRecognizer = UIPanGestureRecognizer(target: self, action: #selector(panGesture))
panRecognizer?.delegate = self
view.addGestureRecognizer(panRecognizer!)
Depending if you want to know which direction you'll have to check out the translation of the view.
#objc func panGesture(sender: UIPanGestureRecognizer){
let translation = sender.translation(in: sender.view)
print(translation.x, translation.y)
}
}
Make sure you have you add the delegate - UIGestureRecognizerDelegate
Hope that gives you a good start

dragging an UIImageView on an UIView always stacks the image under the UIView

I am rather new to iOS and swift 3 programming. At the moment I am working on a little learning project. I have the following problem.
On my screen I have 4 UIViews and 4 UIImageViews. The app allows to “drag and drop” an image onto one of the UIViews. This works pretty well so far. I use Pan Gesture Recognisers for the dragging of UIImages. But for some reason one of the UIViews seems to be in front of the image, meaning that I can drop the image to this area, but I cannot see it - it is layered under the UIView. The other three behave properly, the UIImageView is layered on top of the UIView. In the viewDidLoad() function of the view controller I set the background color of the UIViews to grey. If I don’t do that, the image will be displayed even on the fourth UIView.
I have checked for differences between the four UIView objects but cannot find any. I also tried to recreate the UIView by copying it from one of the the other three.
So my question is: Is there any property which defines that the UIView is layered on top or can be sent to back so that other objects are layered on top of it? Or is there anything else I am missing? Any hints would be very appreciated.
I was not quite sure which parts of the code are relevant, so I posted some of it (but still guess that this is rather a property of the UIView…)
This is where I set the background of the UIViews
override func viewDidLoad() {
super.viewDidLoad()
lbViewTitle.text = "\(viewTitle) \(level) - \(levelPage)"
if (level==0) {
print("invalid level => EXIT")
} else {
loadData(level: level)
originalPositionLetter1 = letter1.center
originalPositionLetter2 = letter2.center
originalPositionLetter3 = letter3.center
originalPositionLetter4 = letter4.center
dropArea1.layer.backgroundColor = UIColor.lightGray.cgColor
dropArea2.layer.backgroundColor = UIColor.lightGray.cgColor
dropArea3.layer.backgroundColor = UIColor.lightGray.cgColor
dropArea4.layer.backgroundColor = UIColor.lightGray.cgColor
}
}
This is the code that moves the image:
#IBAction func hadlePan1(_ sender: UIPanGestureRecognizer) {
moveLetter(sender: sender, dropArea: dropArea4, movedImage: letter1, originalPosition: originalPositionLetter1)
}
func moveLetter(sender: UIPanGestureRecognizer, dropArea : UIView, movedImage : UIImageView, originalPosition : CGPoint) {
let translation = sender.translation(in: self.view)
if let view = sender.view {
view.center = CGPoint(x:view.center.x + translation.x,
y:view.center.y + translation.y)
if sender.state == UIGestureRecognizerState.ended {
let here = sender.location(in: self.view)
if (dropArea.frame.contains(here)) {
movedImage.center = dropArea.center
} else {
movedImage.center = originalPosition
}
}
}
sender.setTranslation(CGPoint.zero, in: self.view)
}
There are two methods that may be useful to you: UIView.sendSubview(toBack:) and UIView.bringSubview(toFront:).
What I think you should do is to call bringSubview(toFront:) when you start dragging the image:
func moveLetter(sender: UIPanGestureRecognizer, dropArea : UIView, movedImage : UIImageView, originalPosition : CGPoint) {
self.view.bringSubview(toFront: movedImage) // <--- add this line!
let translation = sender.translation(in: self.view)
if let view = sender.view {
view.center = CGPoint(x:view.center.x + translation.x,
y:view.center.y + translation.y)
if sender.state == UIGestureRecognizerState.ended {
let here = sender.location(in: self.view)
if (dropArea.frame.contains(here)) {
movedImage.center = dropArea.center
} else {
movedImage.center = originalPosition
}
}
}
sender.setTranslation(CGPoint.zero, in: self.view)
}

Select part of GLKViewController

I'm try to implement this in my project. But I have some troubles with it. I plan to use UiPanGestureRecognizer for change size of rectangle. As I understand, I should be use UIVIew and custom drawRect method?
Add an action for your UIPanGestureRecognizer and use translation:
func wasDragged(gesture: UIPanGestureRecognizer) {
let translation = gesture.translationInView(self.view)
// Do your resizing here, e.g. from a
customView.frame.size.width = currentFrame.width + translation.x
customView.frame.size.height = currentFrame.height + translation.y
if gesture.state == .Ended {
currentFrame = customView.frame
}
}
Using this method, add a CGRect variable to store the currentFrame.

bringSubviewToFront(_:) function breaks a UIPanGestureRecognizer

I have a BoardView class which subclasses UIView. It has several subviews, which all have their own UIPanGestureRecognizer. I use this recognizer to drag around a subview inside my BoardView instance, as such:
func pieceDragged(recognizer: UIPanGestureRecognizer) {
let pieceView = recognizer.view!
if recognizer.state == .Began || recognizer.state == .Changed {
// move the pieceView by the appropriate amount
let translation = recognizer.translationInView(self)
pieceView.center = CGPoint(x: pieceView.center.x + translation.x, y: pieceView.center.y + translation.y)
recognizer.setTranslation(CGPoint.zero, inView: self)
} else if recognizer.state == .Ended {
// do something else
}
}
This works fine.
The problem is that I want the subview that is being dragged around to be on top of all of its siblings, so I made my BoardView instance the delegate of each gesture recognizer and overrode this function:
override func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
let pieceView = gestureRecognizer.view!
bringSubviewToFront(pieceView)
return true
}
This seems to break the entire gesture recognizer: if I attempt to drag aroudn a subview, the pieceDragged(_:) function is called exactly once (where the state of the recognizer is .Began), but no more than that.
If I comment out bringSubviewToFront(pieceView), my code works as before - I can drag around any subview, but it's below some of its siblings.
I'm clueless. What could be going on here?
The problem was that I replaced all my subviews in the layoutSubviews() method (which is automatically called after bringToFront(_:) is called).
Seems like you are going round the houses as well and implementing a method that doesn't really make sense. The delegate method gestureRecognizerShouldBegin(_:) is all about should this recogniser actually start detecting not a place to perform an action.
You already have a suitable place to perform the action you want you could simply update your code to be
func pieceDragged(recognizer: UIPanGestureRecognizer) {
guard let pieceView = recognizer.view else {
return
}
switch recognizer.state {
case .Began:
pieceView.superview?.bringSubviewToFront(pieceView)
case .Changed:
let translation = recognizer.translationInView(self)
recognizer.setTranslation(CGPoint.zero, inView: self)
pieceView.center = CGPoint(x: pieceView.center.x + translation.x, y: pieceView.center.y + translation.y)
default: ()
}
}

Swift UIGestureRecogniser follow finger

I'm making an iOS8 app using Swift. I'd like the user to be able to use gestures to reveal certain parts of the interface. So for example, the user slides their finger up and the view they slid their finger up moves out of the way, following their finger to reveal another view underneath.
What I'd like is a gesture to give a result similar to the notification box that you can pull down from the top of the screen. I've been looking at the documentation and I can't seem to find a suitable gesture.
I saw one called UISwipeGestureRecogniser, but the only problem is, it doesn't follow your finger, it simply runs a function when I slide my finger up / down.
Here's the documentation page:
https://developer.apple.com/documentation/uikit/uigesturerecognizer
You're looking for the UIPanGestureRecognizer. You'll find the Apple Documentation here.
Here's a sample handler that will move a view with your finger. In Interface Builder, add a UIPanGestureRecognizer to a view that you want to be able to drag. Set the delegate to your ViewController. Set the action to this action:
Swift 2.X:
#IBAction func handlePan(gestureRecognizer: UIPanGestureRecognizer) {
if gestureRecognizer.state == .Began || gestureRecognizer.state == .Changed {
let translation = gestureRecognizer.translationInView(self.view)
// note: 'view' is optional and need to be unwrapped
gestureRecognizer.view!.center = CGPointMake(gestureRecognizer.view!.center.x + translation.x, gestureRecognizer.view!.center.y + translation.y)
gestureRecognizer.setTranslation(CGPointMake(0,0), inView: self.view)
}
}
Swift 3:
#IBAction func handlePan(_ gestureRecognizer: UIPanGestureRecognizer) {
if gestureRecognizer.state == .began || gestureRecognizer.state == .changed {
let translation = gestureRecognizer.translation(in: self.view)
// note: 'view' is optional and need to be unwrapped
gestureRecognizer.view!.center = CGPoint(x: gestureRecognizer.view!.center.x + translation.x, y: gestureRecognizer.view!.center.y + translation.y)
gestureRecognizer.setTranslation(CGPoint.zero, in: self.view)
}
}
Of course, you can add the UIPanGestureRecognizer programmatically:
In viewDidLoad for your ViewController, create the recognizer and add it to the view you want to be able to drag:
let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan))
self.someDraggableView.addGestureRecognizer(gestureRecognizer)

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