IOS UITableView中UITextField 弹出键盘时，界面上移

IOS 中键盘遮挡住UITextField的输入框，导致用户体验不好，一直是IOS的难点所在。
自学IOS时间不长，对于这个问题，如下是我的方法，仅供参考。
如果UITextField位于屏幕下方，键盘弹出时会挡住UITextField，建议将UITextField放入UIScrollview或UITableView中。

废话不多说，直接上代码

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)

        //add notification for keyboard did change frame
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "didChangeKeyboardFrame:", name: UIKeyboardDidChangeFrameNotification, object: nil)

        //add notification for keyboard did hide
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "didHideKeyboard:", name: UIKeyboardDidHideNotification, object: nil)
    }

    override func viewWillDisappear(animated: Bool) {
        super.viewWillDisappear(animated)

        //remove keyboard observer
        NSNotificationCenter.defaultCenter().removeObserver(self)
    }

    func didChangeKeyboardFrame(notification: NSNotification) {
        let rect = notification.userInfo![UIKeyboardFrameEndUserInfoKey]!.CGRectValue
        let height = rect.size.height
        var insets = self.tableView.contentInset
        insets.bottom = height
        self.tableView.contentInset = insets
        insets = self.tableView.scrollIndicatorInsets
        insets.bottom = height
        self.tableView.scrollIndicatorInsets = insets
    }

    func didHideKeyboard(notification: NSNotification) {
        var insets = self.tableView.contentInset
        insets.bottom = 0.0
        self.tableView.contentInset = insets
        insets = self.tableView.scrollIndicatorInsets
        insets.bottom = 0.0
        self.tableView.scrollIndicatorInsets = insets
    }

以上代码的tableView可以换成自己的scrollView。
UIScrollView contentInset : 视图在scrollView中的位置
UIScrollView scrollIndicatorInsets : 指定滚动条在scrollerView中的位置