Swift - 在显示时将文本字段移动到键盘上答案

【问题标题】：Swift - move textField over keyboard upon showingSwift - 在显示时将文本字段移动到键盘上
【发布时间】：2018-04-20 06:49:29
【问题描述】：

当它出现时，我需要在键盘上移动一个文本字段。

我正在使用以下代码：

override func viewDidLoad() {
    super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(self.keyBoardWillShow(_:)), name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyBoardWillHide(_:)), name: .UIKeyboardWillHide, object: nil)
}

然后：

@objc func keyBoardWillShow(_ notification: NSNotification) {
    let userInfo:NSDictionary = notification.userInfo! as NSDictionary
    let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! NSValue
    let keyboardRectangle = keyboardFrame.cgRectValue
    let keyboardHeight = keyboardRectangle.height

    UIView.animate(withDuration: 0.4) {
        self.commentViewBottomConstraint.constant = keyboardHeight
        self.view.layoutIfNeeded()
    }
}
@objc func keyBoardWillHide(_ notification: NSNotification) {
    UIView.animate(withDuration: 0.4) {
        self.commentViewBottomConstraint.constant = 0
        self.view.layoutIfNeeded()
    }
}

问题是键盘高度似乎不正确。事实上，视图的底部并没有与键盘对齐。视图和键盘之间有一个空格。

老实说，我不明白我做错了什么......

感谢您的帮助！

【问题讨论】：

标签： ios swift uiview keyboard

【解决方案1】：

我认为问题在于底部约束与安全区域相关。所以我通过添加这个来修复它：

let safeAreaHeight = self.view.safeAreaInsets.bottom
self.commentViewBottomConstraint.constant = keyboardHeight - safeAreaHeight

这是完整的代码：

 @objc func keyBoardWillShow(_ notification: NSNotification) {
    let userInfo:NSDictionary = notification.userInfo! as NSDictionary
    let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! NSValue
    let keyboardRectangle = keyboardFrame.cgRectValue
    let keyboardHeight = keyboardRectangle.height
    let safeAreaHeight = self.view.safeAreaInsets.bottom

    UIView.animate(withDuration: 0.4) {
        self.commentViewBottomConstraint.constant = keyboardHeight - safeAreaHeight
        self.view.layoutIfNeeded()
    }
}

【讨论】：