Swift ScrollView-contentSize不能接受变量Int

Question

Trying to set a scrollView's contentSize and I've run across this issue (Xcode 6.4)...

Both of these work perfectly:

scrollView.contentSize = CGSize(width:self.view.frame.width, height:1000)

scrollView.contentSize = CGSizeMake(self.view.frame.width, 1000)

Once a let (or var) gets involved, these do not work:

let testing = 1000
scrollView.contentSize = CGSize(width:self.view.frame.width, height:testing)

Error: Cannot find an initializer for type 'CGSize' that accepts an argument list of type '(width: CGFloat, height: Int)'

let testing = 1000
scrollView.contentSize = CGSizeMake(self.view.frame.width, testing)

Error: Cannot invoke 'CGSizeMake' with an argument list of type '(CGFloat, Int)'

Answer 1

Change the let statement to the following:

let testing:CGFloat = 1000

You need to do this as the CGSizeMake function requires two parameters of the same type, so you can either make both int s or make them both CGFloat s. In this case it is probably easier to use testing as a CGFloat in the first place. In other cases, you might want to try something like

let testing = 1000
scrollView.contentSize = CGSizeMake(Int(self.view.frame.width), testing)

Or:

let testing = 1000
scrollView.contentSize = CGSizeMake(self.view.frame.width, CGFloat(testing))

So that both are of the same type.

Answer 2

• A number literal doesn't have an explicit type. Its type is inferred at the point that it's evaluated by the compiler.

• A number variable must have an explicit type. The default type is Int

   let testing : CGFloat = 1000.0 scrollView.contentSize = CGSize(width:self.view.frame.width, height:testing)