Change the page title using a short code - wordpress

Question

I am coding a plugin and I use a short code to render a page content. I want to change the page title. I used this:
// Change the title of the page of the charts to add the current month.
add_filter('the_title', 'charts_title', 10, 2);
function charts_title($title, $id) {
$title .= ' ' . date('F Y');
return $title;
}
But it does that for all the posts and pages. Can I do that only for the pages that contains the short code I created ? I tried to do that, but it doesn't work.
add_shortcode('charts-vote', 'charts_vote');
function charts_vote($atts) {
// Add the filter only in the short code function callback.
add_filter('the_title', 'charts_title', 10, 2);
// ... //
return $content;
}
Can someone please help me ?

Answer 1

I understand that the specifics of your set up may require checking for the Shortcode, but maybe a Custom Field could be used for that:
add_filter( 'the_title', 'charts_title_so_15312385', 10, 2 );
function charts_title_so_15312385( $title, $post_id )
{
// Admin area, bail out
if( is_admin() )
return $title;
// Custom field not set, bail out
$mod_title = get_post_meta( $post_id, 'mod_title', true );
if( !$mod_title )
return $title;
// Ok, modify title
$title .= ' ' . date( 'F Y' );
return $title;
}
The Shortcode could even "talk" with the Custom Field for extended configurations.
For ease of use, you could make a Custom Meta Box or use a plugin like Advanced Custom Fields.