Synchronize Frontend- and Admin languages?

Hi!

That’s not a Polylang feature. If you want it, you will have to code it.
To help, the language is stored in the cookie ‘pll_language’ on frontend and in the user meta ‘user_lang’ on admin.

Okay! Confusing as it controls what items are displayed in admin. Polylang must surely somewhere in the plugin influence this? How?

I want to affect the code that saves pll_language and user_lang. Does functions must exist somewhere already. Can I affect them with a filter or something?

I have made a bit of progress now. But stuck. I have described the problem in the code below:

add_action('init', 'my_init');

function my_init()
{
	global $polylang;

		if (!session_id())
		{
	    	session_start();
		}

		if (!empty($_REQUEST['lang']) && !is_numeric($_REQUEST['lang']))
		{
				// Redirect to new lang url
				if (!empty($_SESSION['theme_func_lang']) && $_SESSION['theme_func_lang'] != $_REQUEST['lang'])
				{
					// PROBLEM: This executes even in admin and returns error cause
					// $polylang->choose_lang object doesn't exist there.

					// But even if I remove this code, ans switch language from
					// admin, add this code again and try to update frontend,
					// frontend won't update to the new language.

					$lang = $polylang->model->get_language($_SESSION['theme_func_lang']);

					$polylang->choose_lang->curlang = $lang->curlang;
					do_action('pll_language_defined', $lang->curlang->slug, $lang->curlang);

					unset($_SESSION['theme_func_lang']);

					$polylang->choose_lang->home_requested();

					// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
				}
				else
				{

					$lang = $polylang->model->get_language($_REQUEST['lang']);

					$polylang->curlang = $lang;

						// Update frontend lang
						if (!headers_sent() && PLL_COOKIE !== false && (!isset($_COOKIE[PLL_COOKIE]) || $_COOKIE[PLL_COOKIE] != $lang->slug))
						{
								setcookie(
									PLL_COOKIE,
									$lang->slug,
									time() + 31536000 /* 1 year */,
									COOKIEPATH,
									2 == $polylang->options['force_lang'] ? parse_url($polylang->links_model->home, PHP_URL_HOST) : COOKIE_DOMAIN
								);
						}

						// Update admin lang
						if (!defined('DOING_AJAX') && current_user_can('edit_user', $user_id = get_current_user_id()))
						{
							update_user_meta($user_id, 'pll_filter_content', $lang);
							$polylang->pref_lang = $lang;
						}

					// Flag new lang
					$_SESSION['theme_func_lang'] = $lang->slug;
				}
		}
}