ios - 通过键盘向上滚动后，TextView 没有移回原始位置

Question

编辑:添加 viewDidLoad 代码

所以我做了一些研究来学习如何移动我的 TextView 之一，这样当键盘弹出时，它会向上 ScrollView ，这样键盘就不会覆盖 TextView 。我似乎能够完成这项工作，但现在我的问题是，在关闭键盘后， View 仍保持原样。它不会“快速”回到原来的位置，然后键盘弹出并将 TextView 滚动到一边。我在我的代码中遗漏了什么吗？或者我需要添加一些东西吗？

override func viewDidLoad() {
    super.viewDidLoad()
    self.questionInput.delegate = self
    self.answerInput.delegate = self
    let tap: UITapGestureRecognizer = UITapGestureRecognizer(target:self, action: "DismissKeyboard")
    view.addGestureRecognizer(tap)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardDidShow:", name: UIKeyboardDidShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
}


var activeView: UITextView?


func textViewDidEndEditing(textView: UITextView) {

    self.activeView = nil
}

func textViewDidBeginEditing(textView: UITextView) {

    self.activeView = textView
}

func keyboardDidShow(notification: NSNotification) {
    if let activeView = self.answerInput, keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        let contentInsets = UIEdgeInsets(top: 0.0, left: 0.0, bottom: keyboardSize.height, right: 0.0)
        self.scrollView.contentInset = contentInsets
        self.scrollView.scrollIndicatorInsets = contentInsets
        var aRect = self.view.frame
        aRect.size.height -= keyboardSize.size.height
        if (!CGRectContainsPoint(aRect, activeView.frame.origin)) {
            self.scrollView.scrollRectToVisible(activeView.frame, animated: true)
        }
    }
}

func keyboardWillBeHidden(notification: NSNotification) {
    let contentInsets = UIEdgeInsetsZero
    self.scrollView.contentInset = contentInsets
    self.scrollView.scrollIndicatorInsets = contentInsets
}

我的第二个问题是我读过关于需要注销键盘通知的内容，这是准确的引述..

“当您离开 View Controller 时，不要忘记取消注册这些事件。”

这到底是什么意思？ segueing时是否需要添加代码？

感谢任何帮助，因为我对这两个问题都很困惑。谢谢。

Answer 1

如果您处于开发的初始阶段，您可以使用这个库，它将处理整个项目中的键盘处理

https://github.com/hackiftekhar/IQKeyboardManager

关于你的第二个问题，这里是你需要实现的示例代码

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);
}

如果你使用自动布局，你需要实现它

func keyboardWasShown(notification: NSNotification) {
    var info = notification.userInfo!
    var keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()

    UIView.animateWithDuration(0.1, animations: { () -> Void in
        self.bottomConstraint.constant = keyboardFrame.size.height + 20
    })
}