在swift 3中，您可以执行以下操作

UIApplication.shared.sendAction(#selector(UIResponder.resignFirstResponder), to: nil, from: nil, for: nil)

杰里米的回答不太适合我，我想是因为我在一个选项卡视图中有一个导航堆栈，上面有一个模态对话框。我现在使用下面的，它是为我工作，但你的里程可能会有所不同。

 // dismiss keyboard (mostly macro)
[[UIApplication sharedApplication].delegate dismissKeyboard]; // call this in your to app dismiss the keybaord

// --- dismiss keyboard (in indexAppDelegate.h) (mostly macro)
- (void)dismissKeyboard;

// --- dismiss keyboard (in indexAppDelegate.m) (mostly macro)
// do this from anywhere to dismiss the keybard
- (void)dismissKeyboard {    // from: http://stackoverflow.com/questions/741185/easy-way-to-dismiss-keyboard

    UITextField *tempTextField = [[UITextField alloc] initWithFrame:CGRectZero];

    UIViewController *myRootViewController = <#viewController#>; // for simple apps (INPUT: viewController is whatever your root controller is called.  Probably is a way to determine this progragrammatically)
    UIViewController *uivc;
    if (myRootViewController.navigationController != nil) { // for when there is a nav stack
        uivc = myRootViewController.navigationController;
    } else {
        uivc = myRootViewController;
    }

    if (uivc.modalViewController != nil) { // for when there is something modal
        uivc = uivc.modalViewController;
    } 

    [uivc.view  addSubview:tempTextField];

    [tempTextField becomeFirstResponder];
    [tempTextField resignFirstResponder];
    [tempTextField removeFromSuperview];
    [tempTextField release];

}

这不是很漂亮，但是当我不知道responder是什么时，我辞去firstResponder的方式:

创建一个UITextField，无论是在IB或编程。把它隐藏起来。如果你是用IB写的，就把它链接到你的代码上。 然后，当你想要解散键盘时，你将响应器切换到不可见的文本字段，并立即辞职:

  [self.invisibleField becomeFirstResponder];
  [self.invisibleField resignFirstResponder];

添加一个点击手势识别器到您的视图。并定义为ibaction

你的。m文件就像

    - (IBAction)hideKeyboardGesture:(id)sender {
    NSArray *windows = [UIApplication sharedApplication].windows;
    for(UIWindow *window in windows) [window endEditing:true];
    [[UIApplication sharedApplication].keyWindow endEditing:true];
}

这对我很有效

更新

我找到了另一种简单的方法

简单地声明一个属性:-

@property( strong , nonatomic) UITextfield *currentTextfield;

和一个Tap Gesture Gecognizer:-

@property (strong , nonatomic) UITapGestureRecognizer *resignTextField;

在ViewDidLoad

_currentTextfield=[[UITextField alloc]init];
_resignTextField=[[UITapGestureRecognizer alloc]initWithTarget:@selector(tapMethod:)];

[self.view addGestureRecognizer:_resignTextField];

实现文本字段委托方法didBeginEditing

 -(void)textFieldDidBeginEditing:(UITextField *)textField{


      _currentTextfield=textField;

    }

实现点击手势方法(_resignTextField)

 -(void)tapMethod:(UITapGestureRecognizer *)Gesture{

     [_currentTextfield resignFirstResponder];

 }

你可能也需要覆盖UIViewController disablesautomatickeyboarddismiss来让它在某些情况下工作。如果你有UINavigationController，这可能必须在UINavigationController上完成。