How to enable or disable footer link in magento2.1 with helper function dynamically from xml based on my own config value?

Question

I have my own contact us module in magento.I want to remove default contact us link from footer and add my own link. I have remove default contact page link and add my own link. I want that when my module is disabled then default contactus link will not remove from footer.

<referenceBlock name="contact-us-link" remove="true"/>

<referenceBlock name="footer_links">
    <block class="Magento\Framework\View\Element\Html\Link\Current" name="contact-us-link2" ifconfig="contactus/active_display/enabled_contactus">
        <arguments>
            <argument name="label" xsi:type="string">Contact Us2</argument>
            <argument name="path" xsi:type="string">contactus/front/index</argument>
        </arguments>


    </block>
</referenceBlock>

Answer 1

You can hide or show link from the backend

Stores >> Configuration >> General >> Contacts

You can enable or disable the default link

EDIT

You can do this by observer

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">

     <event name="admin_system_config_changed_section_YourSectionName">
        <observer instance="Namespace\Modulename\Observer\ContactUsLink" name="admin_system_config_changed_section_yoursectionname"/>
    </event>
</config>

ContactUsLink.php

<?php
namespace Pkit\JobPortal\Observer;
use Magento\Framework\Event\Observer as EventObserver;

class ContactUsLink implements \Magento\Framework\Event\ObserverInterface {

    const XML_PATH_CONTACTUS = 'contact/contact/enabled'; //defualt magento contact us system path
    const XML_PATH_YOURCONTACTUS = 'section/group/field'; //your contact us system path


    protected $_scopeConfig;

    protected $_configInterface;

    public function __construct(
        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
        \Magento\Framework\App\Config\ConfigResource\ConfigInterface $configInterface
    )
    {
        $this->_scopeConfig = $scopeConfig;
        $this->_configInterface = $configInterface;
    }

    public function execute(EventObserver $observer)
    {

        if($this->_scopeConfig->getValue(self::XML_PATH_YOURCONTACTUS)){
            $this->_configInterface
                    ->saveConfig(self::XML_PATH_CONTACTUS, 0 , 'default', 0);
        } else if(!$this->_scopeConfig->getValue(self::XML_PATH_YOURCONTACTUS)){
            $this->_configInterface
                    ->saveConfig(self::XML_PATH_CONTACTUS, 1 , 'default', 0);
        }
    }
}