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。

为了扩展Esqarrouth的答案，我总是使用以下方法来解除键盘，特别是如果我正在解除键盘的类没有view属性和/或不是UIView的子类。

UIApplication.shared.keyWindow?.endEditing(true)

并且，为了方便起见，下面是uiapplication类的扩展:

extension UIApplication {

    /// Dismisses the keyboard from the key window of the
    /// shared application instance.
    ///
    /// - Parameters:
    ///     - force: specify `true` to force first responder to resign.
    open class func endEditing(_ force: Bool = false) {
        shared.endEditing(force)
    }

    /// Dismisses the keyboard from the key window of this 
    /// application instance.
    ///
    /// - Parameters:
    ///     - force: specify `true` to force first responder to resign.
    open func endEditing(_ force: Bool = false) {
        keyWindow?.endEditing(force)
    }

}

override func viewDidLoad() {
    super.viewDidLoad()
          
    //Looks for single or multiple taps. 
     let tap = UITapGestureRecognizer(target: self, action: #selector(UIInputViewController.dismissKeyboard))

    //Uncomment the line below if you want the tap not not interfere and cancel other interactions.
    //tap.cancelsTouchesInView = false 

    view.addGestureRecognizer(tap)
}

//Calls this function when the tap is recognized.
@objc func dismissKeyboard() {
    //Causes the view (or one of its embedded text fields) to resign the first responder status.
    view.endEditing(true)
}

如果你打算在多个uiviewcontroller中使用这个功能，这里有另一种方法来完成这个任务:

// Put this piece of code anywhere you like
extension UIViewController {
    func hideKeyboardWhenTappedAround() {
        let tap = UITapGestureRecognizer(target: self, action: #selector(UIViewController.dismissKeyboard))
        tap.cancelsTouchesInView = false            
        view.addGestureRecognizer(tap)
    }
    
    @objc func dismissKeyboard() {
        view.endEditing(true)
    }
}

现在在每个UIViewController中，你要做的就是调用这个函数:

override func viewDidLoad() {
    super.viewDidLoad()
    self.hideKeyboardWhenTappedAround() 
}

这个函数是我的repo中包含的标准函数，它包含了很多有用的Swift扩展，比如这个，看看:https://github.com/goktugyil/EZSwiftExtensions

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)。

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)
}

斯威夫特3:

扩展选择器作为参数，能够做额外的东西在解散函数和cancelsTouchesInView，以防止扭曲与触摸的其他元素的视图。

extension UIViewController {
    func hideKeyboardOnTap(_ selector: Selector) {
        let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: selector)
        tap.cancelsTouchesInView = false
        view.addGestureRecognizer(tap)
    }
}

用法:

override func viewDidLoad() {
    super.viewDidLoad()
    self.hideKeyboardOnTap(#selector(self.dismissKeyboard))
}

func dismissKeyboard() {
    view.endEditing(true)
    // do aditional stuff
}