Overriding method with selector 'touchesBegan:withEvent:' has incompatible type '(NSSet, UIEvent) -> ()'

IosSwiftOverriding

Ios Problem Overview


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'

Ios Solutions


Solution 1 - Ios

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 https://stackoverflow.com/questions/30892254/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)
}

Solution 2 - Ios

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)
}

Solution 3 - Ios

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>
}

Solution 4 - Ios

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 {
         // ...
    }
    // ...
}

Solution 5 - Ios

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.
    }
}

Solution 6 - Ios

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!)
    }

Solution 7 - Ios

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

import UIKit.UIGestureRecognizerSubclass

Solution 8 - Ios

Using Swift 4 and Xcode 9

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {

}

Solution 9 - Ios

  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)
            }
        }
    }

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionSoCorView Question on Stackoverflow
Solution 1 - IosMartin RView Answer on Stackoverflow
Solution 2 - IosHimanshu MahajanView Answer on Stackoverflow
Solution 3 - IosChetan PrajapatiView Answer on Stackoverflow
Solution 4 - IosAhmad GhadiriView Answer on Stackoverflow
Solution 5 - IosHedyloveView Answer on Stackoverflow
Solution 6 - IosjfredsilvaView Answer on Stackoverflow
Solution 7 - IosbeshioView Answer on Stackoverflow
Solution 8 - Iosammar shahidView Answer on Stackoverflow
Solution 9 - IosTalha RasoolView Answer on Stackoverflow