UITextField shouldChangeCharactersInRange获取实时数据并执行联想搜索和搜索

- (UITextField *)searchTextField {

    if(!_searchTextField)
    {
        _searchTextField = [self createTextField];
        _searchTextField.font = [UIFont systemFontOfSize:13];//字号
        _searchTextField.textColor = DEFAULT_TITLE_SUPER_FRONT_COLOR;
//        NSMutableAttributedString *placeholderString = nil;
        if(isCommonUnitEmptyString(self.placeholderString))
        {
            _searchTextField.text = @"";
        }
        else
        {
//            NSMutableAttributedString *placeholderString = [[NSMutableAttributedString alloc] initWithString:@"昵称/个人ID/房间名称" attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:12],NSForegroundColorAttributeName:BGColorHex(CCCCCC)}];
            NSMutableAttributedString *placeholderString = [[NSMutableAttributedString alloc] initWithString:self.placeholderString attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:13],NSForegroundColorAttributeName:BGColorHex(888888)}];
            _searchTextField.attributedPlaceholder = placeholderString;
        }

        _searchTextField.delegate = self;
        _searchTextField.backgroundColor = [UIColor clearColor];
        _searchTextField.keyboardType = UIKeyboardTypeDefault;
        _searchTextField.returnKeyType = UIReturnKeyGoogle;

    }
    return _searchTextField;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if([string isEqualToString:@""])
    {
        if(range.length == string.length)
        {
            if (self.deleteBlock) {
                self.deleteBlock(@"");
            }
        }
        else
        {
            NSString *str = [NSString stringWithFormat:@"%@%@", getNotNilString([textField.text substringToIndex:range.location]), getNotNilString([textField.text substringFromIndex:range.location+range.length])];
            if (self.deleteBlock) {
                self.deleteBlock(str);
            }
        }
        return YES;
    }
    if(![string isEqualToString:@"\n"] && (textField.text.length + string.length > serarchKeyWordMaxLenght))
    {
        return NO;
    }
    if ([string isEqualToString:@"\n"])
    {
//        if (self.deleteBlock) {
//            self.deleteBlock(textField.text);
//        }
        [textField resignFirstResponder];
        //检测到用户点击换行或rentun,执行搜索请求
        NSString *keyWord = [getNotNilString(textField.text) stringByReplacingOccurrencesOfString:@" " withString:@""];
        if(isCommonUnitEmptyString(keyWord))
        {
            return YES;
        }
        if(self.searchBlock)
        {
            self.searchBlock(keyWord);
        }
        [self endEditing:YES];
        return NO;
    }
    else
    {
        NSString *str = [NSString stringWithFormat:@"%@%@%@", getNotNilString([textField.text substringToIndex:range.location]), string, getNotNilString([textField.text substringFromIndex:range.location])];
        if (self.deleteBlock) {
            self.deleteBlock(str);
        }
    }

    return YES;
}