ios - Swift ScrollView - contentSize can't take a variable 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

将语句更改let为以下内容：

let testing:CGFloat = 1000

您需要这样做，因为该CGSizeMake函数需要两个相同类型的参数，因此您可以将两者都设为ints 或将它们都设为CGFloats。在这种情况下，首先将testing其用作 a可能更容易CGFloat。在其他情况下，您可能想尝试类似

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

或者：

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

所以两者都是同一类型。

Answer 2

• 数字文字没有明确的类型。它的类型是在编译器评估它的时候推断出来的。

• 数字变量必须具有显式类型。默认类型是Int

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