UITextView实时跟踪输入文字的个数，超过禁止输入并阶段

#pragma mark - UITextViewDelegate- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{    if([text isEqualToString:@"\n"]){        [textView resignFirstResponder];        return NO;    }        UITextRange *selectedRange = [textView markedTextRange];    UITextPosition *position = [textView positionFromPosition:selectedRange.start offset:0];    if(position && (range.length==0 || text.length==0)){        return YES;    }else{        NSString *str = [textView.text stringByReplacingCharactersInRange:NSMakeRange(range.location, range.length) withString:text];        if(str.length>40){            self.remarkTextView.text = [str substringToIndex:40];            [self.dict setObject:self.remarkTextView.text forKey:@"remark"];            if(self.ticketParamEdit){                self.ticketParamEdit(self.dict, self);            }            return NO;        }else{            [self.dict setObject:str forKey:@"remark"];            if(self.ticketParamEdit){                self.ticketParamEdit(self.dict, self);            }        }    }    return YES;}