ios swift开发中，使用键盘，tableview根据键盘调整高度

1.在viewdidload中，注册如下监听：

        NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)

        NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)

2. 实现对应的监听触发方法：

    func keyboardWillShow(note:NSNotification){

        var userInfo:NSDictionary = note.userInfo!

        var aValue:NSValue = userInfo.objectForKey("UIKeyboardFrameEndUserInfoKey") as! NSValue

        var keyboardRect:CGRect = aValue.CGRectValue()

        keyboardRect = self.view.convertRect(keyboardRect, fromView: nil)

        var keyboardTop:CGFloat = keyboardRect.origin.y

        var newTextViewFrame:CGRect = self.view.bounds

        newTextViewFrame.size.height = keyboardTop - self.view.bounds.origin.y

        var animationDurationValue:NSValue = userInfo.objectForKey("UIKeyboardAnimationDurationUserInfoKey") as! NSValue

        var  animationDuration:NSTimeInterval? = 0.5

        animationDurationValue.getValue(&animationDuration)

        UIView.beginAnimations(nil, context: nil)

        UIView.setAnimationDuration(animationDuration!)

        self._chatView.frame = newTextViewFrame

        UIView.commitAnimations()

    }

    

    func keyboardWillHide(note:NSNotification){

        var userInfo:NSDictionary = note.userInfo!

        var animationDurationValue:NSValue = userInfo.objectForKey("UIKeyboardAnimationDurationUserInfoKey") as! NSValue

        var  animationDuration:NSTimeInterval? = 0.5

        animationDurationValue.getValue(&animationDuration)

        UIView.beginAnimations(nil, context: nil)

        UIView.setAnimationDuration(animationDuration!)

        self._chatView.frame = self.view.bounds;

        UIView.commitAnimations()

    }

3.界面退出时，卸载监听，在

    override func viewWillDisappear(animated: Bool) {

        super.viewWillDisappear(animated)

        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)

        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)

    }