Iterating over NSObject set as a certain type - swift

I have a function that that receives a Set<NSObject> and I need to iterate over the set as a Set<UITouch>. How exactly do I test for this and unwrap the set?
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch in touches {
// ...
}
}


Generally you would use a conditional cast to check each element
for its type. But here, the touches parameter is
documented
as
A set of UITouch instances that represent the touches that are moving
during the event represented by event.
therefore you can force-cast the entire set:
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
for touch in touches as! Set<UITouch> {
// ...
}
}
Note that in Swift 2 the function declaration changed to
func touchesMoved(_ touches: Set<UITouch>, withEvent event: UIEvent?)
(due to the "light-weight generics" in Objective-C) so that a cast is not needed anymore.


Use the as operator to perform type casting:
for touch in touches {
if let aTouch = touch as? UITouch {
// do something with aTouch
} else {
// touch is not an UITouch
}
}

Related

Touchesmoved - updating multiple elements on single drag

I'm trying to update multiple images upon clicking and dragging over the elements. I've implemented touchesbegan, touchesmoved, and touchesended, but I don't know how to make touchesmoved effect multiple images.
I've been scouring the web, but I haven't been able to find any guides on this. If you could point me in the right direction, or provide me with some basic advice, that would be greatly appreciated.
The following is an example image:
Edit: The following is an example image of what should be possible:
What it should look like.
I'd like to be able to effect the other letters in the same way through the same press, changing their pictures. These pictures are temporary images.
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
print("touches began:\(touches)")
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.image = UIImage(named: "slot")!
print("touches moved:\(touches)")
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
self.image = UIImage(named: "tile")!
print("touches ended")
}

If I understood you correctly, that should be something like this:
class ChangableView: UIView {
private var touchedImageView: UIImageView? {
didSet {
if oldValue == touchedImageView { return }
if let oldValue = oldValue {
oldValue.image = UIImage(named: "tile")!
}
if let newValue = touchedImageView {
newValue.image = UIImage(named: "slot")!
}
}
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
guard let touch = touches.first else { return }
updateTouchedImageViewWithTouch(touch, event: event)
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
guard let touch = touches.first else { return }
updateTouchedImageViewWithTouch(touch, event: event)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
touchedImageView = nil
}
}
private extension ChangableView {
func updateTouchedImageViewWithTouch(touch: UITouch, event: UIEvent?) {
let touchPoint = touch.locationInView(self)
let touchedView = self.hitTest(touchPoint, withEvent: event)
touchedImageView = touchedView as? UIImageView
}
}
In addition your UIViewController should have as view a subclass of ChangableView and do not forget to set userInteractionEnabled property to all the UIImageViews to YES.

Override function with sprite kit game

I am migrating my game from swift 1 and I can't figure out how to fix this function. I am trying to detect if no touches are taking place, which should keep the ball still. this is the code i have and keep getting error Invalid redeclaration of touchesBegan. Im not sure how to work around this, I've been stuck for a while and can't get the ball to stop moving when no touches present. Please help, thanks
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
// do nothing if ad is showing
if Ad.share().showing {
return
}
let touch = touches.first! as UITouch
let touchedLocation = touch.locationInNode(self)
// change the speedXFirst of the ball if it starts
if start {
// start move
let moveRight = touchedLocation.x > CGRectGetMidX(self.frame)
let speedX = moveRight ? ballSpeedX : -ballSpeedX
ball.speedXFirst = speedX
}
// start game if it stops
else {
startGame()
}
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) { //error RIGHT HERE
if start {
// stop move
ball.speedXFirst = 0
}

If you ball must be stopped when the user detaches the finger from the screen, probably you want to use:
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
or this if you need to know when the touches were interrupted:
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
}

Track fingers in UIViewController

I want to track down the position of my fingers in a UIViewController. I implemented this with the following function and this is working great!
override func viewDidLoad() {
view.userInteractionEnabled = true
view.multipleTouchEnabled = true
super.viewDidLoad()
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
//Create subview and place it under your finger.
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
//Here methods which tracks the moves of the finger and updates the subviews position.
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
//Remove subview from superview overhere.
}
I have two issues:
When I press more than 5 fingers on the screen, touchesBegin/touchesMoved/touchesEnded will not be called anymore. Even when I place 6 fingers and remove 1.
Sometimes touchesBegan is called from random positions on my screen. TouchesEnded is called for the same point after that.
Should I implement this on another way? I also tried it using UIGestureRecognizer but without success.
I added this function
override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {
}
And this is called when I tap the 6th finger on the screen.

Method does not override any method from it's superclass

I'm trying to create a new override func when i got this error: Method does not override any method from it's superclass
I have already tried to delete the override part but that only gives me another error.
override func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
let touch : UITouch! = touches.anyObject() as! UITouch
location = touch.locationInView(self.view)
person.center = location
}
override func touchesMoved(touches: NSSet!, withEvent event: UIEvent!) {
let touch : UITouch! = touches.anyObject() as! UITouch
location = touch.locationInView(self.view)
person.center = location
}

The correct method signatures are:
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
}

It says method does not overide any method from its super class, what do i do? [duplicate]

Xcode 6.3. Within a class implementing UITextFieldDelegate protocol, I would like to override touchesBegan() method to possibly hide the keyboard. If I avoid a compiler error in the function spec, then there is a complier error trying to read the "touch" from the Set or NSSet, or else the super.touchesBegan(touches , withEvent:event) throws an error. One of these combinations compiled in Xcode 6.2! (So where is documentation to Swift "Set" and how to get an element from one?)
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
// Hiding the Keyboard when the User Taps the Background
if let touch = touches.anyObject() as? UITouch {
if nameTF.isFirstResponder() && touch.view != nameTF {
nameTF.resignFirstResponder();
}
}
super.touchesBegan(touches , withEvent:event)
}
Try:
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) or
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent)
Compiler error:
Overriding method with selector 'touchesBegan:withEvent:' has incompatible type '(NSSet, UIEvent) -> ()'
and
super.touchesBegan(touches , withEvent:event)
also complains
'NSSet' is not implicitly convertible to 'Set'; did you mean to use 'as' to explicitly convert?
Try:
override func touchesBegan(touches: Set<AnyObject>, withEvent event: UIEvent)
Compiler error:
Type 'AnyObject' does not conform to protocol 'Hashable'
Try:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent)
Compiler error at
if let touch = touches.anyObject() as? UITouch
'Set' does not have a member named 'anyObject' BUT the function spec and call to super() are OK!
Try:
override func touchesBegan(touches: NSSet<AnyObject>, withEvent event: UIEvent) -> () or
override func touchesBegan(touches: NSSet<NSObject>, withEvent event: UIEvent)
Compiler error:
Cannot specialize non-generic type 'NSSet'

Swift 1.2 (Xcode 6.3) introduced a native Set type that bridges
with NSSet. This is mentioned in the Swift blog and in the
Xcode 6.3 release notes, but apparently not yet added to the official documentation (update: As Ahmad Ghadiri noted, it is documented now).
The UIResponder method is now declared as
func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent)
and you can override it like this:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
if let touch = touches.first as? UITouch {
// ...
}
super.touchesBegan(touches , withEvent:event)
}
Update for Swift 2 (Xcode 7): (Compare Override func error in Swift 2)
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
if let touch = touches.first {
// ...
}
super.touchesBegan(touches, withEvent:event)
}
Update for Swift 3:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
// ...
}
super.touchesBegan(touches, with: event)
}

With xCode 7 and swift 2.0, use following code:
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
if let touch = touches.first{
print("\(touch)")
}
super.touchesBegan(touches, withEvent: event)
}
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
if let touch = touches.first{
print("\(touch)")
}
super.touchesEnded(touches, withEvent: event)
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
if let touch = touches.first{
print("\(touch)")
}
super.touchesMoved(touches, withEvent: event)
}

Using Swift 3 and Xcode 8
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
}
override func touchesCancelled(_ touches: Set<UITouch>?, with event: UIEvent?) {
// Don't forget to add "?" after Set<UITouch>
}

It is now in the Apple API reference here and for overriding in xCode version 6.3 and swift 1.2 you can use this code:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
if let touch = touches.first as? UITouch {
// ...
}
// ...
}

The current one right now for the newest update as of xCode 7.2 Swift 2.1 on Dec 19, 2015.
Next time you get an error like this again, remove the function and start typing it again "touchesBe..." and xCode should automatically complete it to the newest one for you instead of trying to fix the old one.
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch: AnyObject! in touches {
let touchLocation = touch.locationInNode(self)
//Use touchLocation for example: button.containsPoint(touchLocation) meaning the user has pressed the button.
}
}

What worked for me was:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
if let touch = touches.first as? UITouch {
// ...
}
super.touchesBegan(touches , withEvent:event!)
}

Small addition. For swift to compile w/o error, you need to add
import UIKit.UIGestureRecognizerSubclass

Using Swift 4 and Xcode 9
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first as? UITouch {
if touch.view == self.view{
self.dismiss(animated: true, completion: nil)
}
}
}