override func invalidateIntrinsicContentSize() gives does not override error. Removing override gives conflicting with superclass error

Question

I am using Apple Tutorial "Start Developing iOS Apps (Swift) - implement a custom control, with Xcode 8 and Swift 3. I am doing "Declare a Constant for the Button Size" section but getting an error. Apple suggests that we use the following code.

override func intrinsicContentSize() -> CGSize {  
  let buttonSize = Int(frame.size.height)  
  let width = (buttonSize * starCount) + (spacing * (starCount - 1))  

  return CGSize(width: width, height: buttonSize)  
}  

But, the first error (which is sort of irrelevant to this question) is that in Swift 3, intrinsicContentSize() has been changed to invalidateIntrinsicContentSize(). After using override func invalidateIntrinsicContentSize() I get the following error.

swift:53:19: Method does not override any method from its superclass  

When I remove override, I get the following error.

53:10: Method 'invalidateIntrinsicContentSize()' with Objective-C selector 
'invalidateIntrinsicContentSize' conflicts with method
'invalidateIntrinsicContentSize()' from superclass 'UIView' with the 
same Objective-C selector 

Can anyone please explain what might be going wrong? What can I change or add to get rid of this error?

Thanks

Answer 1

In Swift3, it has been changed to a property and its not available to you as a method. You should override the getter to return your desired size:

override public var intrinsicContentSize: CGSize {
     return CGSize()//your desired size here
}

Please refer to the documents IntrinsicContentSize

Answer 2

迅速，internalContentSize已更改为存储属性，而不是invalidateIntrinsicContentSize（），因此您应尝试覆盖var intrinsicContentSize 。