xcode6 NSObject AnyObject错误

Question

我使用了来自How to move content of UIViewController upwards as Keypad appears using Swift的代码，试图阻止键盘覆盖我的视图。

不知何故，我无法让它工作(主要是因为我的n00b编程“技能”)，这是我遇到的错误：[NSObject: AnyObject] does not have a member named 'valueForKey'在这一行代码：let s:NSValue = sender.userInfo.valueForKey(UIKeyboardFrameBeginUserInfoKey) as NSValue;

我想我将不得不创建某种类型的IBAction，但我没有任何尝试。我该怎么做才能让代码起作用？我为什么要这么做？NSObject是做什么的？

下面是代码：

override func viewDidLoad() {
    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
}

deinit {
    NSNotificationCenter.defaultCenter().removeObserver(self);
}

func keyboardWillShow(sender: NSNotification) {
    let s:NSValue = sender.userInfo.valueForKey(UIKeyboardFrameEndUserInfoKey) as NSValue;
    let rect :CGRect = s.CGRectValue();
    var frame = self.textField.frame;
    frame.origin.y = frame.origin.y - rect.height;
    self.textField.frame = frame;
}

func keyboardWillHide(sender: NSNotification) {
    let s:NSValue = sender.userInfo.valueForKey(UIKeyboardFrameBeginUserInfoKey) as NSValue;
    let rect :CGRect = s.CGRectValue();
    var frame = self.textField.frame;
    frame.origin.y = frame.origin.y + rect.height;
    self.textField.frame = frame;
}

Answer 1

您必须将userInfo转换为NSDictionary，将上述功能替换为下面的函数

func keyboardWillShow(sender: NSNotification) {
    let dict:NSDictionary = sender.userInfo as NSDictionary
    let s:NSValue = dict.valueForKey(UIKeyboardFrameEndUserInfoKey) as NSValue;
    let rect :CGRect = s.CGRectValue();
    var frame = self.textField.frame;
    frame.origin.y = frame.origin.y - rect.height;
    self.textField.frame = frame;
}

func keyboardWillHide(sender: NSNotification) {
    let dict:NSDictionary = sender.userInfo as NSDictionary
    let s:NSValue = dict.valueForKey(UIKeyboardFrameBeginUserInfoKey) as NSValue;
    let rect :CGRect = s.CGRectValue();
    var frame = self.textField.frame;
    frame.origin.y = frame.origin.y + rect.height;
    self.textField.frame = frame;
}

编辑

//Add this above viewDidLoad
    var selecteTextFieldOriginalY:CGFloat = 0.0;

//write in viewDidLoad
    override func viewDidLoad() {
        super.viewDidLoad()
        NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardDidShowNotification, object: nil);
        NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardDidHideNotification, object: nil);
    }

//Replace these functions
    func keyboardWillShow(sender: NSNotification) {
        let dict:NSDictionary = sender.userInfo as NSDictionary
        let s:NSValue = dict.valueForKey(UIKeyboardFrameEndUserInfoKey) as NSValue;
        let rect :CGRect = s.CGRectValue();

        var frame = self.textField.frame;
        selecteTextFieldOriginalY = frame.origin.y;

//Adjust 80 according to your need actually if is for padding and quickTypeView
        var offset = (rect.height - ((self.view.frame.height - self.textField.frame.origin.y)+self.textField.frame.size.height))+80;
        print(offset)
        frame.origin.y = offset>0 ? frame.origin.y - offset : frame.origin.y ;
        UIView.animateWithDuration(0.3, animations:{
            self.textField.frame = frame;

            }
        )
    }

    func keyboardWillHide(sender: NSNotification) {
        let dict:NSDictionary = sender.userInfo as NSDictionary
        let s:NSValue = dict.valueForKey(UIKeyboardFrameBeginUserInfoKey) as NSValue;
        let rect :CGRect = s.CGRectValue();
        var frame = self.textField.frame;
        frame.origin.y = selecteTextFieldOriginalY ;

        UIView.animateWithDuration(0.3, animations:{
            self.textField.frame = frame;

            })
    }