我没有看到它被提到过，但是NotificationCenter可以告诉你键盘何时打开和关闭。例如，如果你想改变cancelsTouchesInView或一起删除手势识别器，这可以被使用。

例子:

var dismissKeyboardGestureRecognizer = UITapGestureRecognizer()

override func viewDidLoad() {
    super.viewDidLoad()

    //Setup dismiss keyboard gesture
    self.dismissKeyboardGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(dismissKeyboard))

    //Add Notifications
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardDidShow), name:UIResponder.keyboardDidShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardDidHide), name:UIResponder.keyboardDidHideNotification, object: nil)
}

@objc func keyboardDidShow() {
    dismissKeyboardGestureRecognizer.cancelsTouchesInView = true
    view.addGestureRecognizer(dismissKeyboardGestureRecognizer)
}

@objc func keyboardDidHide() {
    dismissKeyboardGestureRecognizer.cancelsTouchesInView = false
    view.removeGestureRecognizer(dismissKeyboardGestureRecognizer)
}

@objc func dismissKeyboard() {
    view.endEditing(true)
}

下面是关于如何在Xcode 6.1中使用Swift消除键盘的回答:

import UIKit

class ItemViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet var textFieldItemName: UITextField!

    @IBOutlet var textFieldQt: UITextField!

    @IBOutlet var textFieldMoreInfo: UITextField!


    override func viewDidLoad() {
        super.viewDidLoad()

        textFieldItemName.delegate = self
        textFieldQt.delegate = self
        textFieldMoreInfo.delegate = self
    }

                       ...

    /**
     * Called when 'return' key pressed. return NO to ignore.
     */
    func textFieldShouldReturn(textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }


   /**
    * Called when the user click on the view (outside the UITextField).
    */
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        self.view.endEditing(true)
    }

}

(此信息的来源)。

这里有一个简单的方法:

let endEditingTapGesture = UITapGestureRecognizer(target: view, action: #selector(UIView.endEditing(_:)))
endEditingTapGesture.cancelsTouchesInView = false
view.addGestureRecognizer(endEditingTapGesture)

Swift 4工作

创建扩展如下所示，并在你的基本视图控制器中调用hideKeyboardWhenTappedAround()。

//
//  UIViewController+Extension.swift
//  Project Name
//
//  Created by ABC on 2/3/18.
//  Copyright © 2018 ABC. All rights reserved.
//

import UIKit

extension UIViewController {
    func hideKeyboardWhenTappedAround() {
        let tapGesture = UITapGestureRecognizer(target: self, 
                         action: #selector(hideKeyboard))
        view.addGestureRecognizer(tapGesture)
    }

    @objc func hideKeyboard() {
        view.endEditing(true)
    }
}

最重要的是调用Base视图控制器这样就不需要在所有视图控制器中调用所有时间。

当视图中有多个文本字段时

为了遵循@modocache的建议避免调用view. enditing()，您可以跟踪成为第一响应器的文本字段，但这很混乱且容易出错。

另一种方法是在视图控制器中的所有文本字段上调用resignFirstResponder()。下面是一个创建所有文本字段集合的示例(在我的情况下，验证代码无论如何都需要):

@IBOutlet weak var firstName: UITextField!
@IBOutlet weak var lastName: UITextField!
@IBOutlet weak var email: UITextField!

var allTextFields: Array<UITextField>!  // Forced unwrapping so it must be initialized in viewDidLoad
override func viewDidLoad()
{
    super.viewDidLoad()
    self.allTextFields = [self.firstName, self.lastName, self.email]
}

有了可用的集合，就可以简单地遍历所有这些集合:

private func dismissKeyboard()
{
    for textField in allTextFields
    {
        textField.resignFirstResponder()
    }
}

所以现在你可以在你的手势识别器(或任何适合你的地方)中调用遣散键盘()。缺点是在添加或删除字段时必须维护UITextFields列表。

欢迎评论。如果在不是第一响应者的控件上调用resignFirstResponder()有问题，或者如果有一种简单且保证无bug的方法来跟踪当前的第一响应者，我很乐意听到它!

作为一个新手程序员，当人们给出更熟练和不必要的回答时，可能会感到困惑……你不需要做上面所示的任何复杂的事情!

这是最简单的选择……在这种情况下，你的键盘出现在响应文本字段-在你的触摸屏函数中，只需添加resignFirstResponder函数。如下所示-键盘将关闭，因为First Responder被释放(退出Responder链)…

override func touchesBegan(_: Set<UITouch>, with: UIEvent?){
    MyTextField.resignFirstResponder()
}