字典无法识别密钥类型（已更新）

Question

我有

func keyboardWillShow(aNotification: NSNotification)    {
        //Collect information about keyboard using its notification.
        let info = aNotification.userInfo
        let duration = (info[UIKeyboardAnimationDurationUserInfoKey] as NSValue) as Double
        let curve : AnyObject? = info[UIKeyboardAnimationCurveUserInfoKey]
        let kbFrame : AnyObject? = (info[UIKeyboardFrameEndUserInfoKey] as NSValue).CGRectValue().size
}

如何在没有

的情况下阅读这些内容

“[NSObject：AnyObject]？没有名为'subscript'的成员”错误？

在xCode的beta版本中，这已经奏效了，但是从 xCode 6.1 开始，它已经无法正常运行了。

Answer 1

userInfo是可选的Dictionary，因此您可以使用可选绑定来解包值。而CGSize是一个结构，而不是一个对象，所以将AnyObject更改为CGSize。

if let info = aNotification.userInfo {
    let duration = (info[UIKeyboardAnimationDurationUserInfoKey] as NSValue) as Double
    let curve : AnyObject? = info[UIKeyboardAnimationCurveUserInfoKey]
    let kbFrame: CGSize = (info[UIKeyboardFrameEndUserInfoKey] as NSValue).CGRectValue().size
}