Using isKindOfClass with Swift

Question

I m trying to pick up a bit of Swift lang and I m wondering how to convert the following Objective-C into Swift   -  void touchesBegan  NSSet   touches withEvent  UIEvent   event        super touchesBegan touches withEvent event        UITouch  touch    touches anyObject        if   touch view isKindOfClass  UIPickerView class             your touch was in a uipickerview     do whatever you have to do           More specifically I need to know how to use isKindOfClass in the new syntax   override func touchesBegan touches  NSSet  withEvent event  UIEvent                  if                  your touch was in a uipickerview

User · Answer

You can combine the check and cast into one statement   let touch   object anyObject   as UITouch if let picker   touch view as  UIPickerView               Then you can use picker within the if block

User · Answer

override func touchesBegan touches  NSSet  withEvent event  UIEvent         super touchesBegan touches  withEvent  event      let touch   UITouch   touches anyObject   as UITouch      if touch view isKindOfClass UIPickerView                   Edit  As pointed out in  Kevin s answer  the correct way would be to use optional type cast operator as   You can read more about it on the section Optional Chaining sub section Downcasting   Edit 2  As pointed on the other answer by user  KPM  using the is operator is the right way to do it

User · Answer

The proper Swift operator is is    if touch view is UIPickerView          touch view is of type UIPickerView     Of course  if you also need to assign the view to a new constant  then the if let     as      syntax is your boy  as Kevin mentioned  But if you don t need the value and only need to check the type  then you should use the is operator

User · Answer

Another approach using the new Swift 2 syntax is to use guard and nest it all in one conditional   guard let touch   object AnyObject   as  UITouch  let picker   touch view as  UIPickerView else       return   Do Nothing     Do something with picker

User · Answer

I would use   override func touchesBegan touches  NSSet  withEvent event  UIEvent         super touchesBegan touches  withEvent  event      let touch   UITouch   touches anyObject   as UITouch      if let touchView   touch view as  UIPickerView

[ios] Using isKindOfClass with Swift

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