Wordpress - custom post type, displaying the parent and child categories

Question

So I'm reasonably new to Wordpress, but have been able to solve most issues by myself up until now.

I have a custom post type - lets call it Machines . And in those machines, there is a category called Machine_type . And say I've made a machine type called Scissor Lifts , then another machine type called electric scissor lifts which is a child of scissor lifts .

I'd like to display this information on the single post page - so on the electric scissor lifts page, i'd like to display breadcrumbs like Machines - Scissor Lifts - Electric Scissor Lifts. But this seems almost impossible! I have tried using many different tutorials, but they seem to always display Machines - - - Final machine name , without the actual 2 categories I'd like to display!

It seems sort of crazy that there's no simple inbuilt call for Category and Child Category! I was using this:

<?php 
    $terms = get_the_terms( $post->ID , 'machine_type' ); 
    foreach ( $terms as $term ) {
        $term_link = get_term_link( $term, 'machine_type' );
        if( is_wp_error( $term_link ) )
            continue;
        echo '<p>Machine Type: <a href="' . $term_link . '">' . $term->name . '</a></p>';
    } 
?>

But this obviously just dumps all the information out, no way to separate the parent and child categories nicely.

EDIT:

Update on this problem: I've finally found some code which seems like it's tackling the right problem:

 <?php 
// get top level terms
$parents = get_terms( 'machine_type', array( 'parent' => 0 ) );
// get post categories
$categories = get_the_terms( $post->ID, 'machine_type' );
// output top level cats and their children
foreach( $parents as $parent ):
// output parent name and link
echo '<a href="' . get_term_link( $parent ) . '">' . $parent->name . '</a>: ';
// initialize array to hold child links
$links = array();
foreach( $categories as $category ):
    if( $parent->term_id == $category->parent ):
        // put link in array
        $links[] = '<a href="' . get_term_link( $category ) . '">' . $category->name .      '</a>';
    endif;
endforeach;
// join and output links with separator
echo join( ', ', $links );
endforeach;

?> 

However, what it outputs isn't quite right. For example, on a machine which is categorised as a Boom Lift, and also an Articulated Electric Boom Lift, it's now displaying: "Boom lift: Articulated Booms (electric)Scissor lift: Spider-lift:"

So it's adding on 2 other categories which aren't applicable to this machine. Any ideas?

Answer 1

$wcatTerms = get_terms('product_cat', array('hide_empty' => 0, 'orderby' => 'ASC',  'parent' =>0));
foreach($wcatTerms as $wcatTerm) : 
    echo $wcatTerm->name;
    $wsubargs = array('hierarchical'=>1,'show_option_none'=>'','hide_empty'=>0,'parent'=>$wcatTerm->term_id,'taxonomy'=>'product_cat');
    $wsubcats = get_categories($wsubargs);
    foreach ($wsubcats as $wsc):
        echo $wsc->name;
    endforeach;
endforeach; 

Use this it's display two level of category name and product name.

Answer 2

This may help yo

<?php 

    /********************** List out the parent and child inside parent ***/
    $taxonomyName = "your_taxonomy";
    $term = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) ); 
    if ($term->parent == 1) {  
    wp_list_categories('taxonomy=your_taxonomy&depth=1&show_count=0
    &title_li=&child_of=' . $term->term_id);

    } else {

    wp_list_categories('taxonomy=your_taxonomy&show_count=0
    &title_li=&child_of=' . $term->parent); 
    }
    ?>