Magento 2.1 : How to overwrite default page layout in Block

Question

I have a custom module having layout XML file for the front end, in which the default page layout configuration is set to one column, I wish to give the user the ability to change the configuration as specified in the system configurations(like 2columns-left, 2columns-right, 3coulmns). I can get the values from configuration via helper in to the block file prepareLayout ,I would like to know if we can set the layout just like the pagetitle , metakeyowords we use to set. How can we set and overwrite default values in prepare layout in block file? Thanks.

The XML default value is :

<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" layout="1column" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">

Answer 1

You can set page layout from the controller action. Suppose this is your action file avilable at this location.

app/code/Vendor/Extension/Controller/Youraction/Action.php

Put this code like this.

<?php 
namespace Vendor\Extension\Controller\Youraction;

use Magento\Framework\Controller\ResultFactory;

class Action extends \Magento\Framework\App\Action\Action
{

    public function __construct(
        \Magento\Framework\App\Action\Context $context,
        \Magento\Framework\View\Result\PageFactory $resultPageFactory
    ) {
        $this->resultPageFactory = $resultPageFactory;
        parent::__construct($context);
    }

    public function execute()
    {
        $page = $this->resultPageFactory->create(false, ['isIsolated' => true]); 

        // YOUR LOGIC TO GET SELECTED LAYOUT FROM ADMIN 
        $youradminlayout = 'XYZ'; 
        $page->getConfig()->setPageLayout($youradminlayout);
        return $page;
    }
}