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)
    }

}

  import UIKit

  class ItemViewController: UIViewController, UITextFieldDelegate {

  @IBOutlet weak var nameTextField: UITextField!

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

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。

//Simple exercise to demonstrate, assuming the view controller has a //Textfield, Button and a Label. And that the label should display the //userinputs when button clicked. And if you want the keyboard to disappear //when clicken anywhere on the screen + upon clicking Return key in the //keyboard. Dont forget to add "UITextFieldDelegate" and 
//"self.userInput.delegate = self" as below

import UIKit

class ViewController: UIViewController,UITextFieldDelegate {

    @IBOutlet weak var userInput: UITextField!
    @IBAction func transferBtn(sender: AnyObject) {
                display.text = userInput.text

    }
    @IBOutlet weak var display: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()

//This is important for the textFieldShouldReturn function, conforming to textfieldDelegate and setting it to self
        self.userInput.delegate = self
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

//This is for the keyboard to GO AWAYY !! when user clicks anywhere on the view
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        self.view.endEditing(true)
    }


//This is for the keyboard to GO AWAYY !! when user clicks "Return" key  on the keyboard

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

}

对于Swift 3来说，这非常简单

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    self.view.endEditing(true)
}

如果你想隐藏键盘按回车键

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

但在第二种情况下，你还需要通过委托从所有文本字段的ViewController在主。故事板

Swift 5只要两行就够了。添加到你的viewDidLoad应该工作。

 let tapGesture = UITapGestureRecognizer(target: view, action: #selector(UIView.endEditing))
 view.addGestureRecognizer(tapGesture)

如果你的点击手势阻止了一些其他的触摸，那么添加这一行:

tapGesture.cancelsTouchesInView = false