Adding a custom variable to get_posts - wordpress

Question

In wordpress, I have custom pages and inside the pages I'm trying to call the most recent posts for a specific category.
Doing so, I added this to create the variable...
$cat = get_post_meta($post->ID, "mom_cat", true);
And in the custom field of the page, I added mom_cat = (variable #)
In my post, I am trying to show the recent posts based o the variable category # I put in the custom field. I tried this, but it didn't work...
<?php
global $post;
$myposts = get_posts('numberposts=4&category=$cat' );
foreach($myposts as $post) :
?>
Hoever that is not working. How do I add a variable to "category = " in order to display a category based on my custom field setting?
Thanks

Answer 1

You shouldn't be using Custom Fields to define categories when Wordpress has all of the tools for you at your disposal. What you should do is find where your custom post is being registered, and add:
'taxonomies' => array('category')
...to your argument array. This will enable you to check off the categories that your custom posts require. If you can't find where the custom post type is being registered, add this instead to your functions.php file:
add_action('init', 'add_category_to_custom');
function add_category_to_custom()
{
register_taxonomy_for_object_type('category', 'custom_post_name');
}
THEN you can reference your custom post like so:
$posts = get_posts(array('numberposts' => 4, 'category' => $cat_ID, 'post_type' => 'custom_post_name'));
UPDATE: I wouldn't advise using Pages to display Category information, but I'm sure you have your reasons. I would still avoid placing category IDs within Custom Fields, simply because if one of your category IDs change, then it can cause LOTS of problems.
What I would advise in your case is to name those particular Pages exactly the same as their matching categories. Then do something like this:
<?php
/*
IF THE PAGE HAS A MATCHING CATEGORY,
DISPLAY 5 OF THE MOST RECENT POSTS IN THAT CATEGORY
*/
if($catID = get_cat_ID(get_the_title(get_the_ID())))
{
$posts = get_posts(array('numberposts' => 5, 'category' => $catID));
foreach($posts as $post) : setup_postdata($post);
?>
<!-- POST HTML GOES HERE -->
<?php
endforeach;
}
?>