Swift Beta 5中的字符串到浮点转换

Question

以下代码在Beta 5中不再起作用.

let device = UIDevice.currentDevice()
if (device.systemVersion.bridgeToObjectiveC().floatValue < 8.0) {
    [skipped]
}    

此外,不可能将字符串向下转换为浮动.

let device = UIDevice.currentDevice()
let version: Float = device.systemVersion as Float

上面的代码段会返回'String' is not convertible to 'Float'错误.

任何想法我们现在应该如何测试操作系统版本？谢谢.

Answer 1

floatValue是一种方法NSString.
Since bridgeToObjectiveC()Xcode 6 Beta 5不再提供,您可以使用as运算符将Swift转换String为NSString:

(device.systemVersion as NSString).floatValue