ios - UITextField 键盘不解除

Question

我有一个 UIViewController，里面有一个 UITextField，当我点击离开或关闭 View 时，我试图关闭键盘。然而，当我调用 resignFirstResponder() 时，键盘仍然没有关闭，我不太清楚为什么。这是我的代码:

class MessageViewController: UIViewController, UITextFieldDelegate {
    var messageTextField : UITextField = UITextField()

    override func viewDidLoad() {
        ...
        messageTextField.frame = CGRectMake(10, UIScreen.mainScreen().bounds.size.height-50, UIScreen.mainScreen().bounds.size.width-80, 40)
    messageTextField.delegate = self
    messageTextField.borderStyle = UITextBorderStyle.Line
    messageTextField.becomeFirstResponder()
    self.view.addSubview(messageTextField)

    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
        ...
    }

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

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        self.view.endEditing(true)
        println("Touched")
    }

    func keyboardWillShow(notification: NSNotification) {
        var keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey]as? NSValue)?.CGRectValue()
        let messageFrame = messageTextField.frame
        let newY = messageFrame.origin.y - keyboardSize!.height
        messageTextField.frame = CGRectMake(messageFrame.origin.x, newY, messageFrame.size.width, messageFrame.size.height)
    }

    func keyboardWillHide(notification: NSNotification) {
        var keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey]as? NSValue)?.CGRectValue()
        let messageFrame = messageTextField.frame
        let newY = messageFrame.origin.y - keyboardSize!.height
        messageTextField.frame = CGRectMake(messageFrame.origin.x, newY, messageFrame.size.width, messageFrame.size.height)
    }

}

有谁知道为什么键盘没有消失？我以编程方式将 UITextField 添加到 View 中，而不是使用 Storyboard。这有什么不同吗？

Answer 1

 class ViewController: UIViewController,UITextFieldDelegate {

确认协议(protocol)

messageTextField.delegate=self

设置委托(delegate)

  func textFieldShouldReturn(textField: UITextField!) -> Bool  
    {
        messageTextField.resignFirstResponder()
        return true;
    }

使用此代码..