如果你有多个数字字段，我建议子类化UITextField来创建一个NumericTextField，它总是显示一个带有done按钮的数字键盘。然后，简单地将你的数值字段与接口构建器中的这个类关联起来，你就不需要在任何视图控制器中添加任何额外的代码。下面是我在Xcode 8.0中使用的Swift 3.0类。

class NumericTextField: UITextField {
   let numericKbdToolbar = UIToolbar()

    // MARK: Initilization
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.initialize()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.initialize()
    }

    // Sets up the input accessory view with a Done button that closes the keyboard
    func initialize()
    {
        self.keyboardType = UIKeyboardType.numberPad

        numericKbdToolbar.barStyle = UIBarStyle.default
        let space = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.flexibleSpace, target: nil, action: nil)
        let callback = #selector(NumericTextField.finishedEditing)
        let donebutton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.done, target: self, action: callback)
        numericKbdToolbar.setItems([space, donebutton], animated: false)
        numericKbdToolbar.sizeToFit()
        self.inputAccessoryView = numericKbdToolbar
    }

    // MARK: On Finished Editing Function
    func finishedEditing()
    {
        self.resignFirstResponder()
    }
}

斯威夫特4.2

class NumericTextField: UITextField {
    let numericKbdToolbar = UIToolbar()

    // MARK: Initilization
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.initialize()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.initialize()
    }

    // Sets up the input accessory view with a Done button that closes the keyboard
    func initialize()
    {
        self.keyboardType = UIKeyboardType.numberPad

        numericKbdToolbar.barStyle = UIBarStyle.default
        let space = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.flexibleSpace, target: nil, action: nil)
        let callback = #selector(NumericTextField.finishedEditing)
        let donebutton = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.done, target: self, action: callback)
        numericKbdToolbar.setItems([space, donebutton], animated: false)
        numericKbdToolbar.sizeToFit()
        self.inputAccessoryView = numericKbdToolbar
    }

    // MARK: On Finished Editing Function
    @objc func finishedEditing()
    {
        self.resignFirstResponder()
    }
}

另一个解决方案。如果屏幕上有其他非数字填充文本字段，则完美。

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIToolbar* numberToolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];
    numberToolbar.barStyle = UIBarStyleBlackTranslucent;
    numberToolbar.items = @[[[UIBarButtonItem alloc]initWithTitle:@"Cancel" style:UIBarButtonItemStyleBordered target:self action:@selector(cancelNumberPad)],
                         [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
                         [[UIBarButtonItem alloc]initWithTitle:@"Apply" style:UIBarButtonItemStyleDone target:self action:@selector(doneWithNumberPad)]];
    [numberToolbar sizeToFit];
    numberTextField.inputAccessoryView = numberToolbar;
}

-(void)cancelNumberPad{
    [numberTextField resignFirstResponder];
    numberTextField.text = @"";
}

-(void)doneWithNumberPad{
    NSString *numberFromTheKeyboard = numberTextField.text;
    [numberTextField resignFirstResponder];
}

这是我遇到的最简单的解决办法。我是从《iOS 5开发入门》这本书中学到的。

假设数字字段名为numberField。

In ViewController, add the following method: -(IBAction)closeKeyboard:(id)sender; In ViewController.m, add the following code: -(IBAction)closeKeyboard:(id)sender { [numberField resignFirstResponder]; } Go back to nib file. Open Utilities pan. Open the Identity inspector under Utilities pan. Click on the View (in nib file) once. Make sure you have not clicked on any of the items in the view. For the sake of clarification, you should see UIView under Class in Identity inspector. Change the class from UIView to UIControl. Open Connection Inspector. Click and drag Touch Down and drop the arrow on File Owner icon. (FYI... File Owner icon is displayed on the left of View and appears as a hollow cube with yellow frame.) Select the method: closeKeyboard. Run the program.

现在，当你点击视图背景的任何地方，你应该能够解散键盘。

希望这能帮助你解决问题。: -)

如果我们告诉视图控制器的视图结束编辑，我们也可以让“user touched somewhere else”解决方案更简单:

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
 { 
      [super touchesBegan:touches withEvent:event];

      [self.view endEditing:YES]; //YES ignores any textfield refusal to resign
 }

．.． 假设“触摸其他地方会取消键盘”是视图中任何其他可编辑字段所期望的行为。

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

以下是对Luda的回答的全面检查，并进行了以下更改:

附件视图会自动调整到应用程序框架的宽度 避免使用已弃用的常量UIBarButtonItemStyleBordered Done按钮被实例化为UIBarButtonSystemItemDone

目前“Done”按钮位于附件视图的中央。您可以通过删除相关一侧的空格将其定位在左侧或右侧。

我省略了“取消”按钮，因为默认键盘也没有这个按钮。如果你确实想要一个“取消”按钮，我建议你实例化它为一个UIBarButtonSystemItemCancel，并确保你没有丢弃文本字段中的原始值。在Luda的回答中实现的“取消”行为会用空字符串覆盖值，这可能不是你想要的。

- (void)viewDidLoad {
  [super viewDidLoad];
  float appWidth = CGRectGetWidth([UIScreen mainScreen].applicationFrame);
  UIToolbar *accessoryView = [[UIToolbar alloc]
                              initWithFrame:CGRectMake(0, 0, appWidth, 0.1 * appWidth)];
  UIBarButtonItem *space = [[UIBarButtonItem alloc]
                            initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace
                            target:nil
                            action:nil];
  UIBarButtonItem *done = [[UIBarButtonItem alloc]
                           initWithBarButtonSystemItem:UIBarButtonSystemItemDone
                           target:self
                           action:@selector(selectDoneButton)];
  accessoryView.items = @[space, done, space];
  self.valueField.inputAccessoryView = accessoryView;
}

- (void)selectDoneButton {
  [self.valueField resignFirstResponder];
}

有关构建附件视图的更多信息，请参阅Apple关于数据输入自定义视图的文档。你可能会想要参考UIToolbar和UIBarButtonItem的参考页面。