我知道这个问题已经被回答过很多次了，但下面是我对这个问题的看法。

我发现samvermette和ribeto的回答非常有用，还有maxpower在ribeto的回答中的评论。但这些方法存在一个问题。matt在samvermette的回答中提到的问题是，如果用户想要在其中粘贴带有换行符的东西，键盘将隐藏而不粘贴任何东西。

所以我的方法是上述三种解决方案的混合，只有检查输入的字符串是否为新行，当字符串的长度为1时，我们确保用户是键入而不是粘贴。

以下是我所做的:

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
    NSRange resultRange = [text rangeOfCharacterFromSet:[NSCharacterSet newlineCharacterSet] options:NSBackwardsSearch];
    if ([text length] == 1 && resultRange.location != NSNotFound) {
        [textView resignFirstResponder];
        return NO;
    }

    return YES;
}

就像matt对samvermette的评论一样，我也不喜欢检测“\n”的想法。返回键在UITextView中是有原因的，当然是去下一行。

在我看来，最好的解决方案是模仿iPhone的消息应用程序-这是在键盘上添加工具栏(和按钮)。

我从以下博客文章中得到了代码:

http://www.iosdevnotes.com/2011/02/iphone-keyboard-toolbar/

步骤:

-添加工具栏到你的XIB文件-设置高度为460

-添加工具栏按钮项(如果尚未添加)。如果需要右对齐，还可以将灵活的工具栏按钮项添加到XIB，并移动工具栏按钮项

-创建将按钮项目链接到resignFirstResponder的动作，如下所示:

- (IBAction)hideKeyboard:(id)sender {
    [yourUITextView resignFirstResponder];
}

套:

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];

    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

- (void)keyboardWillShow:(NSNotification *)notification {
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3];

    CGRect frame = self.keyboardToolbar.frame;
    frame.origin.y = self.view.frame.size.height - 260.0;
    self.keyboardToolbar.frame = frame;

    [UIView commitAnimations];
}

- (void)keyboardWillHide:(NSNotification *)notification {
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3];

    CGRect frame = self.keyboardToolbar.frame;
    frame.origin.y = self.view.frame.size.height;
    self.keyboardToolbar.frame = frame;

    [UIView commitAnimations];
}

我发现josebama的回答是这个帖子中最完整、最干净的答案。

下面是Swift 4的语法:

func textView(_ textView: UITextView, shouldChangeTextIn _: NSRange, replacementText text: String) -> Bool {
    let resultRange = text.rangeOfCharacter(from: CharacterSet.newlines, options: .backwards)
    if text.count == 1 && resultRange != nil {
        textView.resignFirstResponder()
        // Do any additional stuff here
        return false
    }
    return true
}

我使用这段代码来更改响应器。

 - (BOOL)textView:(UITextView*) textView shouldChangeTextInRange: (NSRange) range replacementText: (NSString*) text
    {
        if ([text isEqualToString:@"\n"]) {
            //[textView resignFirstResponder];
            //return YES;
            NSInteger nextTag = textView.tag + 1;
            // Try to find next responder
            UIResponder* nextResponder = [self.view viewWithTag:nextTag];
            if (nextResponder) {
                // Found next responder, so set it.
                [nextResponder becomeFirstResponder];
            } else {
                // Not found, so remove keyboard.
                [textView resignFirstResponder];
            }
            return NO; 


            return NO;
        }
        return YES;

    }

//你可以使用这个…

步骤1。第一步是确保声明了对UITextViewDelegate协议的支持。这是在你的头文件中完成的，例如这里的头文件叫做

EditorController。h:

@interface EditorController : UIViewController  {
  UITextView *messageTextView;
}

@property (nonatomic, retain) UITextView *messageTextView;

@end

步骤2。接下来你需要将控制器注册为UITextView的委托。从上面的例子继续，这里是我如何用EditorController作为委托初始化UITextView…

- (id) init {
    if (self = [super init]) {
        // define the area and location for the UITextView
        CGRect tfFrame = CGRectMake(10, 10, 300, 100);
        messageTextView = [[UITextView alloc] initWithFrame:tfFrame];
        // make sure that it is editable
        messageTextView.editable = YES;

        // add the controller as the delegate
        messageTextView.delegate = self;
    }

步骤3。现在拼图的最后一块是采取行动响应shouldCahngeTextInRange消息如下:

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range 
  replacementText:(NSString *)text
{
    // Any new character added is passed in as the "text" parameter
    if ([text isEqualToString:@"\n"]) {
        // Be sure to test for equality using the "isEqualToString" message
        [textView resignFirstResponder];

        // Return FALSE so that the final '\n' character doesn't get added
        return FALSE;
    }
    // For any other character return TRUE so that the text gets added to the view
    return TRUE;
}

斯威夫特

func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
    if text == "\n" {
        textView.resignFirstResponder()
    }
    return true
}