new WP_Query( $args ) and is_single() Not Working

Hi there,

You could read more about conditional tags here. Remember to hook the wrapper function of is_single after wp_query ran if you are using it in functions.php or give it a priority to run later.

To do this in template files you could create custom query:
$query = new WP_Query( array( 'post_type' => 'post' ) );

You could check the post type in the loop:

if( $query->have_posts() ) { 
    if( 'post' == $query->post_type ) {
    // Do something with single post
    }

    if( 'page' == $query->post_type ) {
    // Do something with single page
    }

    if( 'book' == $query->get_post_type() ) {
    // Do something with book post type
    }
}

Or you could create a function and give it a higher priority:

function where_am_i()
{
    if (is_single()) {
        // Do something with single post
    }

    if (is_page()) {
        // Do something with single page
    }
}

add_action('the_post', 'where_am_i', 135);

You could create a post object and check by ID:

function where_am_i($post_ID)
{
    global $post;
    if ($post->ID == $post_ID) {
        // Do something here
    }
}

add_action('the_post', 'where_am_i', 135);

The procedural is_query() only reflects the main query object for the request. But there is also a class method WP_Query::is_single() you can use for new, custom queries.

$query = new WP_Query( array( 'post_type' => 'post' ) );
if ( $query->is_single()) {
  //do something?
}

This is a bad example because the new query’s arg is not a single sort of arg. Typically with custom queries you’d already know if it’s for a single post or not. None the less, it’s how you would check if a custom query is single or not.