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

斯威夫特3: 关闭键盘的最简单方法:

  //Dismiss keyboard method
    func keyboardDismiss() {
        textField.resignFirstResponder()
    }

    //ADD Gesture Recignizer to Dismiss keyboard then view tapped
    @IBAction func viewTapped(_ sender: AnyObject) {
        keyboardDismiss()
    }

    //Dismiss keyboard using Return Key (Done) Button
    //Do not forgot to add protocol UITextFieldDelegate 
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        keyboardDismiss()

        return true
    }

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

如何解散键盘时，你点击任何地方关闭它

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

     view.addGestureRecognizer(tap)
 }
 //Calling this function when the tapped
 @objc func dismissKeyboard() {

    view.endEditing(true)
 }

在Swift 4中，添加@objc:

在viewDidLoad中:

let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.dismissKeyboard))
view.addGestureRecognizer(tap)

功能:

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

因为我编辑的@King-Wizard的回答被拒绝了，所以发布了一个新的答案。

让你的类成为UITextField的委托并重写touchesBegan。

斯威夫特4

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet var textField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        textField.delegate = self
    }

    //Called when 'return' key is pressed. Return false to keep the keyboard visible.
    func textFieldShouldReturn(textField: UITextField) -> Bool {
        return true
    }

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

}