Post Templates and Post ID's

Question

I am trying to make use of the Single template for single posts ( I have a custom one). But for some reason my posts get overridden instead of displaying new data.

This is the setup I have right now

<div class="details">
<?php global $post;
 $category_id=get_the_category($post->ID);

$announcements = new WP_Query(); 
$announcements->query('showposts=1&cat=$category_id');
while ( $announcements->have_posts() ) :  $announcements->the_post(); ?>  

    <p><strong>Published by:<span itemprop="publisher"><?php echo 
get_post_meta($post->ID, 'Publisher','true');?></strong></p>

<?php endwhile;?>
</div>

Answer 1

But for some reason my posts get overridden instead of displaying new data.

The problem is here: $announcements->query('showposts=1&cat=$category_id');

You are trying to use a variable inside a single quote string. Variables do not expand inside single quotes so instead of asking for cat=1, or cat=2, you are literally asking for cat=$category_id-- just like that, spelled out in full.

What you need instead are double quotes: $announcements->query("showposts=1&cat=$category_id");. Variables do expand in double quote.

Or better, an array-- far more readable and maintainable:

$args = array(
  'posts_per_page' => 1,
  'cat' => $category_id,
);

Note: showposts is deprecated. Use posts_per_page.

Answer 2

You need to Pass arguments into the new Object like so.

$category_id = get_the_category( $post->ID );

$args = array(
    'posts_per_page' => 1,
    'category'       => $category_id
);

$announcements = new WP_Query( $args ); 

This page should shine some light on your code for you, I think you've got a few typo's within it and how you call the loop is in the slightly wrong order. WP_Query in Codex.

Answer 3

I tried that, but it still overrides for instance

the_title(), get_post_meta($post->ID, 'key', 'true'), the_post_thumbnail(),

and pretty much all of them gets overriden(What I mean is when I make two posts using the same template, the fields, titles and images get overridden.) Here is how I did it:

<?php
$category_id = get_the_category( $post->ID ); $args =  

array('posts_per_page' => 1, 'category' => $category_id); $announcements = 
new WP_Query( $args );

while($announcements->have_posts()): $announcements->the_post();

?>
<div class="cover"><?php the_post_thumbnail(); ?></div>
<p><strong><span itemprop="title"><?php the_title();?></span></strong></p>
</div>

<?php endwhile;?>