你应该添加UIToolbar到顶部UITextView，而不是使用shouldChangeTextIn

在Swift 4中

let toolbar = UIToolbar(frame: CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 50))
        toolbar.barStyle = .default
        toolbar.items = [
            UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil),
            UIBarButtonItem(title: "Done", style: .done, target: self, action: #selector(doneAction))
        ]
        textView.inputAccessoryView = toolbar

@objc func doneAction(){
 self.textView.resignFirstResponder()
}

使用导航控制器托管一个栏来解除键盘:

在.h文件中:

UIBarButtonItem* dismissKeyboardButton;

在.m文件中:

- (void)viewDidLoad {
    dismissKeyboardButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(dismissKeyboard)];
}

-(void)textViewDidBeginEditing:(UITextView *)textView {
    self.navigationItem.rightBarButtonItem = dismissKeyboardButton;
}

-(void)textFieldDidBeginEditing:(UITextField *)textField {
    self.navigationItem.rightBarButtonItem = dismissKeyboardButton;
}

-(void)dismissKeyboard {
    [self.textField resignFirstResponder];
    [self.textView resignFirstResponder];
    //or replace this with your regular right button
    self.navigationItem.rightBarButtonItem = nil;
}

不要忘记为textView设置委托-否则resignfirstresponder将无法工作。

在viewDidLoad中添加一个观察者

[[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(textViewKeyPressed:) name: UITextViewTextDidChangeNotification object: nil];

然后使用选择器检查"\n"

-(void) textViewKeyPressed: (NSNotification*) notification {

  if ([[[notification object] text] hasSuffix:@"\n"])
  {
    [[notification object] resignFirstResponder];
  }
}

它确实使用“\n”，而不是专门检查返回键，但我认为这是可以的。

更新

参见下面ribto的答案，它使用[NSCharacterSet newlineCharacterSet]来代替\n

迅速回答:

override func viewDidLoad() {
    super.viewDidLoad()
    let tapGestureReconizer = UITapGestureRecognizer(target: self, action: "tap:")
    view.addGestureRecognizer(tapGestureReconizer)
}

func tap(sender: UITapGestureRecognizer) {
    view.endEditing(true)
}

你也可以隐藏键盘时，触摸在视图屏幕:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
     UITouch * touch = [touches anyObject];
     if(touch.phase == UITouchPhaseBegan) {
        [txtDetail resignFirstResponder];
      }
 }