使用扩展的Swift 3解决方案。如果你在你的应用程序中有几个数值的UITextField对象，这是理想的，因为它可以灵活地决定，对于每个UITextField，当点击完成或取消时是否执行自定义操作。

//
//  UITextField+DoneCancelToolbar.swift
//

import UIKit

extension UITextField {
    func addDoneCancelToolbar(onDone: (target: Any, action: Selector)? = nil, onCancel: (target: Any, action: Selector)? = nil) {     
        let onCancel = onCancel ?? (target: self, action: #selector(cancelButtonTapped))
        let onDone = onDone ?? (target: self, action: #selector(doneButtonTapped))

        let toolbar: UIToolbar = UIToolbar()
        toolbar.barStyle = .default
        toolbar.items = [
            UIBarButtonItem(title: "Cancel", style: .plain, target: onCancel.target, action: onCancel.action),
            UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil),
            UIBarButtonItem(title: "Done", style: .done, target: onDone.target, action: onDone.action)
        ]
        toolbar.sizeToFit()

        self.inputAccessoryView = toolbar
    }

    // Default actions:  
    func doneButtonTapped() { self.resignFirstResponder() }
    func cancelButtonTapped() { self.resignFirstResponder() }
}

使用默认动作的示例:

//
// MyViewController.swift
//

@IBOutlet weak var myNumericTextField: UITextField! {
    didSet { myNumericTextField?.addDoneCancelToolbar() }
}

使用自定义完成动作的示例:

//
// MyViewController.swift
//

@IBOutlet weak var myNumericTextField: UITextField! {
    didSet { 
        myNumericTextField?.addDoneCancelToolbar(onDone: (target: self, action: #selector(doneButtonTappedForMyNumericTextField))) 
    }
}

func doneButtonTappedForMyNumericTextField() { 
    print("Done"); 
    myNumericTextField.resignFirstResponder() 
}

 let pickerView = UIPickerView()
   
 var yearpickerToolbar: UIToolbar?
   
    func createPickerView() {
          
           pickerView.delegate = self
           textfield.inputView = pickerView }
   
   
     func dismissPickerView() {
           let toolBar = UIToolbar()
           toolBar.sizeToFit()
   
           toolBar.isUserInteractionEnabled = true
           textfield.inputAccessoryView = toolBar
           textfield.delegate = self
   
   
   yearpickerToolbar = UIToolbar()
           yearpickerToolbar?.autoresizingMask = .flexibleHeight
   
           //add buttons
           let cancelButton = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action:#selector(cancelBtnClicked(_:)))
           cancelButton.tintColor = UIColor.blue
           let flexSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
           
           let doneButton = UIBarButtonItem(title: "Done", style: .plain , target: self, action: #selector(self.doneBtnClicked(_ :) ))
           doneButton.tintColor = UIColor.blue
   
           doneButton.setTitleTextAttributes([NSAttributedString.Key.foregroundColor:
   UIColor.black], for: .normal)
           cancelButton.setTitleTextAttributes([NSAttributedString.Key.foregroundColor:
   UIColor.black], for: .normal)
           
           yearpickerToolbar?.items = [cancelButton, flexSpace, doneButton]
           textfield.inputAccessoryView = yearpickerToolbar }
   
   @objc func cancelBtnClicked(_ button: UIBarButtonItem?) {
           self.view.endEditing(true)
           
       }
   
       @objc func doneBtnClicked(_ button: UIBarButtonItem?) {
           self.view.endEditing(true)
       }

我所见过的技巧是创建一个与整个视图大小相同的自定义透明按钮，然后在其click方法中，让文本字段辞去first responder。因此，用户可以单击字段之外的任何地方来取消键盘。

所有这些关于找到键盘视图并在第三行添加done按钮的实现(这就是为什么按钮。y = 163 b/c键盘的高度是216)是脆弱的，因为iOS不断改变视图层次结构。例如，上述代码都不适用于iOS9。

我认为更安全的方法是找到最顶层的视图，通过[[UIApplication sharedApplication] windows] lastObject]，并在它的左下角添加按钮，doneButton.frame = CGRectMake(0, screen_height - 53,106,53);//人像模式

Swift 2.2 /我用了Dx_的答案。然而，我希望所有的键盘都有这个功能。所以在我的基类中，我把代码:

func addDoneButtonForTextFields(views: [UIView]) {
    for view in views {
        if let textField = view as? UITextField {
            let doneToolbar = UIToolbar(frame: CGRectMake(0, 0, self.view.bounds.size.width, 50))

            let flexSpace = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace, target: nil, action: nil)
            let done = UIBarButtonItem(title: "Done", style: .Done, target: self, action: #selector(dismissKeyboard))

            var items = [UIBarButtonItem]()
            items.append(flexSpace)
            items.append(done)

            doneToolbar.items = items
            doneToolbar.sizeToFit()

            textField.inputAccessoryView = doneToolbar
        } else {
            addDoneButtonForTextFields(view.subviews)
        }
    }
}

func dismissKeyboard() {
    dismissKeyboardForTextFields(self.view.subviews)
}

func dismissKeyboardForTextFields(views: [UIView]) {
    for view in views {
        if let textField = view as? UITextField {
            textField.resignFirstResponder()
        } else {
            dismissKeyboardForTextFields(view.subviews)
        }
    }
}

然后只需调用addDoneButtonForTextFields在self.view.subviews在viewDidLoad(或willDisplayCell如果使用表格视图)添加完成按钮到所有键盘。

最简单的方法是:创建自定义透明按钮并将其放置在左下角，它将具有与UIKeyboardTypeNumberPad中的空白空间相同的CGSize。切换(显示/隐藏)这个按钮在textField成为firstresponder，按钮点击分别。