ios - 在 Swift 4 中升级后未调用 textFieldShouldReturn

Question

我有一个 View Controller ，上面有一些 UITextField。当 UITextField 获得焦点时，如果我点击键盘上的 Return 键，我将转到下一个 UITextField。如果下一个 UITextField 位于键盘下方，我将 View 向上移动。

一切都很好，直到昨天我将应用程序升级到 Swift 4 后，经过一些更改。现在它不再起作用了。我加载了 Swift 3 版本，它工作得很好。问题是我没有看到任何区别，也无法弄清楚。

class ServerWizardVC: UIViewController, UITextViewDelegate, UIDocumentMenuDelegate, UIDocumentPickerDelegate, FileManagerDelegate

@IBOutlet weak var tfServerURL: UITextField!
@IBOutlet weak var tfServerUser: UITextField!
@IBOutlet weak var tfServerPassword: UITextField!
@IBOutlet weak var tfServerPort: UITextField!

override func viewDidLoad()
{
    print("ServerWizardVC > viewDidLoad")

    super.viewDidLoad()

    tfServerURL.tag = 0

    registerForKeyboardNotifications()
    deregisterFromKeyboardNotifications()
}

override func viewWillAppear(_ animated: Bool)
{
    print("ServerWizardVC > viewWillAppear")

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
}

func registerForKeyboardNotifications()
{
    print("ServerWizardVC > registerForKeyboardNotifications")

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
}

func deregisterFromKeyboardNotifications()
{
    print("ServerWizardVC > deregisterFromKeyboardNotifications")

    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

@objc func keyboardWillShow(notification:NSNotification)
{
    print("ServerWizardVC > keyboardWillShow")

    let userInfo:NSDictionary = notification.userInfo! as NSDictionary
    let keyboardFrame:NSValue = userInfo.value(forKey: UIKeyboardFrameEndUserInfoKey) as! NSValue
    let keyboardRectangle = keyboardFrame.cgRectValue
    let keyboardHeight = keyboardRectangle.height

    keyboardHeightValue = keyboardHeight
}

@objc func keyboardWasShown(notification: NSNotification)
{
    print("ServerWizardVC > keyboardWasShown")
}

@objc func keyboardWillBeHidden (notification: NSNotification)
{
    print("ServerWizardVC > keyboardWillBeHidden")
}

func textFieldShouldReturn(_ textField: UITextField) -> Bool
{
    print("ServerWizardVC > textFieldShouldReturn")

    if let nextField = tfServerURL.superview?.viewWithTag(textField.tag + 1) as? UITextField
    {
        nextField.becomeFirstResponder()

        checkTextFieldPosition(tfTag: textField.tag + 1)
    }
    else
    {
        vMainView.frame.origin.y = 0

        textField.resignFirstResponder()
    }

    return false
}

func checkTextFieldPosition(tfTag : Int)
{
    print("ServerWizardVC > checkTextFieldPosition")

    let keyboardTop = mainViewHeight - keyboardHeightValue
    let tfServerPasswordTop =  tfServerPassword.frame.origin.y

    if(tfTag == 3)
    {
        if((keyboardTop < tfServerPasswordTop) && (vMainView.frame.origin.y == 0))
        {
            let yPosition = vMainView.frame.origin.y - keyboardHeightValue + 100
            vMainView.frame.origin.y = yPosition
        }
    }
}

我将此归咎于 Swift 4 升级的原因是我什至没有接触过这个类，其他一切正常。
有什么我想念的吗？

Answer 1

textFieldShouldReturn 是一个 UITextFieldDelegate 函数，但您的类改为符合 UITextViewDelegate。将符合性替换为 UITextFieldDelegate:

class ServerWizardVC: UIViewController, UITextFieldDelegate, UIDocumentMenuDelegate, UIDocumentPickerDelegate, FileManagerDelegate