Sorting Posts by Date - get_blogs_of_user_id()

Question

I am a newbie who needs to produce a chronological list of recent posts from all sites to which a user is subscribed on a WordPress multisite network.

Using the code below, I am able to produce a list where the posts are ordered chronologically (DESC) but grouped by site:

1. Site A Wednesday
2. Site A Tuesday
3. Site A Monday
4. Site B Wednesday
5. Site B Tuesday
6. Site B Monday

I need to produce a list where all posts are ordered chronologically:

1. Site A Wednesday
2. Site B Wednesday
3. Site A Tuesday
4. Site B Tuesday
5. Site A Monday

6. Site B Monday

           $user = get_current_user_id();
           $blogs = get_blogs_of_user( $user );
                if( $blogs ) {
                foreach( $blogs as $blog ) {
                   switch_to_blog( $blog->userblog_id );
                           $query = new WP_Query ('posts_per_page=2');
                                   if ($query->have_posts()) :
                                           while ($query->have_posts()) : $query->the_post();
   
                                           <li>
                                           <a href="<?php echo $string; ?>$
                                           </li>
   
                                            <?php
                                           endwhile;                      $
                   restore_current_blog();
   
                           }
        }
   ?>
   

   ?>

When I have attempted to apply 'order by' to the WP_Query using (new WP_Query( array( 'order by' => 'date' ), I'm producing the first list above (a list ordered chronologically, grouped by site). I have the feeling that I'm supposed to be sending the output of WP_Query to an array, sorting the array, and then printing this to the page, but as I am extremely new to all of this, I could really use some guidance at this point. Thanks.

Answer 1

You can build an array of all post items, and then sort them by date at the end of your querying:

$blogs = get_blogs_of_user( get_current_user_id() );

if ( $blogs ) {
    $items = array();

    foreach ( $blogs as $blog ) {
        switch_to_blog( $blog->userblog_id );
        $posts = get_posts( 'posts_per_page=2' );
        foreach ( $posts as $post ) {
            // Use the timestamp to sort all posts by later.
            $timestamp = strtotime( $post->post_date_gmt );

            // Just in case another published at *exactly* same time.
            while ( isset( $items[ $timestamp ] ) )
                $timestamp++;

            // Add our HTML for this post to the stack.
            // You can't store the post object and work on it later as we'll be outside the scope of this particular blog.
            $items[ $timestamp ] = sprintf( '<li><a href="%s">%s</a></li>', get_permalink( $post->ID ), get_the_title( $post->ID  ) );
        }
    }

    restore_current_blog();

    if ( $items ) {
        // Sort by latest to oldest.
        krsort( $items );

        // Display!
        echo '<ul>';
            echo implode( "\n", $items );
        echo '</ul>';       
    }
}