即使我在 Swift、Xcode 6 中声明，也会切换“预期声明”错误
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/26643222/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
switch 'expected declaration' error even when i have declared in Swift, Xcode 6
提问by Ben Oneill
I get an error saying "expected declaration" by the switch statement https://www.dropbox.com/s/3cjeo3sxg0zw431/Screen%20Shot%202014-10-30%20at%2001.01.48.png?dl=0
我在 switch 语句https://www.dropbox.com/s/3cjeo3sxg0zw431/Screen%20Shot%202014-10-30%20at%2001.01.48.png?dl=0 中收到一条错误消息，说“预期声明”
let questionSelected = Int(arc4random_uniform(1))
switch questionSelected{
case 0:
let x = "(question goes here)"
}
回答by Steve Rosenberg
The cases must be exhaustive otherwise you must have a default statement. I modified the case 0: just to get it to execute in a playground.
案例必须详尽无遗，否则您必须有一个默认声明。我修改了 case 0: 只是为了让它在操场上执行。
let questionSelected = Int(arc4random_uniform(1))
switch questionSelected{
case 0:
let x = "(question goes here)"
default:
break
}
Okay, went an extra step. This works. Hook up the label to a storyboard.
好的，多走了一步。这有效。将标签连接到故事板。
class ViewController: UIViewController {
@IBOutlet weak var questionBox: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
let questionSelected = Int(arc4random_uniform(1))
switch questionSelected{
case 0:
questionBox.text = "Does this work?"
default:
questionBox.text = "Does this work better?"
}
}
}
Second update:
第二次更新：
func thisCodeMustBeInAFunction() {
let questionSelected = Int(arc4random_uniform(1))
switch questionSelected{
case 1:
questionBox.text = "(question goes here)"
default:
break
}
}
