注意：

textFiledDidChange方法中限制输入文字数量前，不可以直接修改 textField.text = text，需要进行判断前后文字是否变化了;否则会造成高亮文本直接进入文本框内，造成问题。那么禁止输入空格和换行，推荐最好在下面的方法里面做。

//过滤相关文字

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSString *tem = [[string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]componentsJoinedByString:@""];
    if (![string isEqualToString:tem]) {
        return NO;
    }
    return YES;
}

如果你确实想在textViewDidChange中处理掉空格和换行符号，你可以这样，毕竟可以减少代码。

-(void)textViewDidChange:(UITextView *)textView
{
   //最大限制字数
    CGFloat maxLength = 0;
    if(textView==_textView_note)
    {
        maxLength=500;
    }
    else if(textView==_textViewFloor)
    {
        
        // 去除空格和换行(判断前后文字是否变化了)
        NSString *text = [textView.text trim];
        if (![text isEqualToString:textView.text]) {
            NSRange textRange = [textView selectedRange];
            textView.text = text;
            [textView setSelectedRange:textRange];
        }
        
        maxLength=50;
    }
    NSString *toBeString = textView.text;
    
    //获取高亮文本范围= 临时插入的需要用户确认的文本长度.确认输入以后，变成0
    //获取高亮部分
    UITextRange *selectedRange = [textView markedTextRange];
    UITextPosition *position = [textView positionFromPosition:selectedRange.start offset:0];
    if (!position || !selectedRange)
    {
        if (toBeString.length > maxLength)
        {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:maxLength];
            if (rangeIndex.length == 1)
            {
                textView.text = [toBeString substringToIndex:maxLength];
            }
            else
            {
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, maxLength)];
                textView.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}

1. UITextField去除emoji并且限制输入文字数量

[textField addTarget:self action:@selector(textFiledEditChanged:) forControlEvents:UIControlEventEditingChanged]; 

- (void)textFiledDidChange:(UITextField *)textField
{
    //禁止emoji输入
    if (textField.text.length > 0) {
        NSString *text = [self disable_emoji:textField.text];
        if (![text isEqualToString:textField.text]) {
            textField.text = text;
        }
    }
    //后面可以是 限制字数的代码
    NSInteger maxLength = 50;
    NSString *toBeString = textField.text;
    
    //获取标记文本范围= 临时插入的需要用户确认的文本长度.确认输入以后，变成0
    UITextRange *selectedRange = [textField markedTextRange];
    UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
    if (!position)
    {
        if (toBeString.length > maxLength)
        {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:maxLength];
            if (rangeIndex.length == 1)
            {
                textField.text = [toBeString substringToIndex:maxLength];
            }
            else
            {
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, maxLength)];
                textField.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}

2.UITextView去除emoji并且限制输入文字数量

- (void)textViewDidChange:(UITextView *)textView{
      if (textView.text.length > 0) {
        // 禁止系统表情的输入
           NSString *text = [self disable_emoji:textView.text];
         if (![text isEqualToString:textView.text]) {
          NSRange textRange = [textView selectedRange];
          textView.text = text;
          [textView setSelectedRange:textRange];
          }
     }
    //限制输入字数
//获取高亮文本范围= 临时插入的需要用户确认的文本长度.确认输入以后，变成0
    //获取高亮部分
    UITextRange *selectedRange = [textView markedTextRange];
    UITextPosition *position = [textView positionFromPosition:selectedRange.start offset:0];
    if (!position || !selectedRange)
    {
        if (toBeString.length > maxLength)
        {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:maxLength];
            if (rangeIndex.length == 1)
            {
                textView.text = [toBeString substringToIndex:maxLength];
            }
            else
            {
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, maxLength)];
                textView.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
    
}

下面是disable_emoji方法的代码

- (NSString *)disable_emoji:(NSString *)text
{
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"[^\\u0020-\\u007E\\u00A0-\\u00BE\\u2E80-\\uA4CF\\uF900-\\uFAFF\\uFE30-\\uFE4F\\uFF00-\\uFFEF\\u0080-\\u009F\\u2000-\\u201f\r\n]" options:NSRegularExpressionCaseInsensitive error:nil];
    NSString *modifiedString = [regex stringByReplacingMatchesInString:text
                                                               options:0
                                                                 range:NSMakeRange(0, [text length])
                                                          withTemplate:@""];
    return modifiedString;
}