当 UITableView 中有 UITextFields 时如何使用 swift 管理键盘？

Question

我正在尝试寻找一种方法来避免键盘在动态 UITableViews 中不阻塞选定的 UITextField。

我知道这是一个常见问题，对此有很多答案。但是，我找到的答案要么在 Obj-C 中，要么不涉及动态 UITableView。

我的表格视图有自己的 UITableViewCell，所以 UITextFields 连接到它。

另外，我想在输入 UITextField 时刷新单元格。我可以将该信息（我猜是单元格的 IndexPath.row？）传递给 UIViewController 并让它监听更改并应用重新加载单元格方法吗？

这是我的相关代码：

class favCell: UITableViewCell, UITextFieldDelegate {

    @IBOutlet weak var deciPadField: UITextField!

    @objc func doneClicked(){
        updateTotalWorth()
        deciPadField.resignFirstResponder()
        deciPadField.endEditing(true)
    }

    func textFieldDidBeginEditing(_ textField: UITextField) {
        deciPadField.becomeFirstResponder()
    }

    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let currentString: NSString = (textField.text ?? "") as NSString
        let newString = currentString.replacingCharacters(in: range, with: string)
        return  newString.count <= 10
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        updateTotalWorth()
        deciPadField.resignFirstResponder()
        return true
    }

    private func textViewDidEndEditing(_ textView: UITextView) {
        updateTotalWorth()
        deciPadField.endEditing(true)
    }
}

更新：

如果我可以从 UITableViewCell 访问我的 ViewControllers 视图，下面的代码就可以解决问题：

func animateTextField(textField: UITextField, up: Bool) {
    let movementDistance:CGFloat = -130
    let movementDuration: Double = 0.3
    var movement:CGFloat = 0

    if up {
        movement = movementDistance
    } else {
        movement = -movementDistance
    }
    UIView.beginAnimations("animateTextField", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(movementDuration)

    // Below line giving error, could not find the view. My ListVC.view should be referred to.
    self.view.frame = self.view.frame.offsetBy(dx: 0, dy: movement)

    UIView.commitAnimations()
}


func textFieldDidBeginEditing(textField: UITextField) {
    self.animateTextField(textField: textField, up:true)
}

func textFieldDidEndEditing(textField: UITextField) {
    self.animateTextField(textField: textField, up:false)
}

谢谢！

Answer 1

好吧，我终于想出了如何解决这个问题。我实现了这个答案：https://stackoverflow.com/a/41040630/4441676

解决的代码如下：

在 ViewController 的 ViewDidLoad 里面添加了两个观察者，如下：

// Notification Observers
    NotificationCenter.default.addObserver(self, selector: #selector(ListVC.keyboardWillShow(notification:)), name: Notification.Name.UIKeyboardDidShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(ListVC.keyboardWillHide(notification:)), name: Notification.Name.UIKeyboardDidHide, object: nil)

并添加了相关的两个功能：

@objc func keyboardWillShow(notification: Notification) {
    if let keyboardHeight = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue.height {
        tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardHeight, 0)
    }
}

@objc func keyboardWillHide(notification: Notification) {
    UIView.animate(withDuration: 0.2, animations: {
        // For some reason adding inset in keyboardWillShow is animated by itself but removing is not, that's why we have to use animateWithDuration here
        self.tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
    })
}

在连接UITextFields的UITableViewCell中，简单实现UITextField Delegate，并在键盘显示/隐藏时添加相关的Notification.posts：

deciPadField.delegate = self

func textFieldDidBeginEditing(_ textField: UITextField) {
    NotificationCenter.default.post(name: Notification.Name.UIKeyboardDidShow, object: self)
}

func textFieldDidEndEditing(_ textField: UITextField) {
    NotificationCenter.default.post(name: Notification.Name.UIKeyboardDidHide, object: self)
}

我有 inputAccessoryView，所以通过以下方式处理关闭键盘：

// Decipad config for adding Done button above itself
let toolBar = UIToolbar()
toolBar.sizeToFit()
let flexiableSpace = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.flexibleSpace, target: nil, action: nil)
let doneButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.done, target: self, action: #selector(self.doneClicked))
toolBar.setItems([flexiableSpace, doneButton], animated: false)

@objc func doneClicked(){
    updateTotalWorth()
    deciPadField.resignFirstResponder()
    deciPadField.endEditing(true)
}

希望这对其他人有帮助。