如果 - 否则 Swift
If - else in Swift
我可以显示警报,但它有一些问题:
- 标题没有出现
我无法使 if 语句部分起作用。弹出的警报仅显示:
the message numbers must be 24 or less
连同关闭按钮,永不改变。
使用 XCode 6.3 和 iOS 8.
var title: String!
if difference > hoursLabel {
title = "Sorry!"
}
else if difference < hoursLabel {
title = "That's better!"
}
let message = "Number must be 24 or less"
var alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Close", style: .Default, handler: nil))
self .presentViewController(alert, animated: true, completion: nil)
根据您提供的内容,问题似乎出在使用 else if
,而不是仅 else
解决方案一:
var title: String!
if difference > hoursLabel {
title = "Sorry!"
}
else {
title = "That's better!"
}
方案二:
let title = (difference > hoursLabel) ? "Sorry": "That's better!" ;
我可以显示警报,但它有一些问题:
- 标题没有出现
我无法使 if 语句部分起作用。弹出的警报仅显示:
the message numbers must be 24 or less
连同关闭按钮,永不改变。
使用 XCode 6.3 和 iOS 8.
var title: String!
if difference > hoursLabel {
title = "Sorry!"
}
else if difference < hoursLabel {
title = "That's better!"
}
let message = "Number must be 24 or less"
var alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Close", style: .Default, handler: nil))
self .presentViewController(alert, animated: true, completion: nil)
根据您提供的内容,问题似乎出在使用 else if
,而不是仅 else
解决方案一:
var title: String!
if difference > hoursLabel {
title = "Sorry!"
}
else {
title = "That's better!"
}
方案二:
let title = (difference > hoursLabel) ? "Sorry": "That's better!" ;