Display Custom Post Type Metabox Data - wordpress

Question

I'm having a problem displaying metabox data in a page template wp_query. I get this error:
Notice: Array to string conversion
Here is my code:
<?php
// WP_Query arguments
$args = array (
'post_type' => array( 'portfolio' ),
'ignore_sticky_posts' => true,
'posts_per_page' => '10',
);
// The Query
$portfolio_query = new WP_Query( $args );
// The Loop
if ( $portfolio_query->have_posts() ) {
while ( $portfolio_query->have_posts() ) {
$portfolio_query->the_post();
echo '<div id="portfolio">';
echo '<div class="featured_img">';
echo '' . " " . get_the_post_thumbnail() . '';
echo '</div>';
echo '<div class="portfolio">';
echo the_title( '<h2>', '</h2>' );
echo '<p>' . the_excerpt() . '</p>';
echo '<p>' . get_post_meta( get_the_ID($post->id , 'project_metabox', false) ) . '</p>';
echo '</div>';
echo '</div>';
}
} else {
echo "<h1>There are no portfolio pieces to view.</h1>";
}
// Restore original Post Data
wp_reset_postdata(); ?>
I've tried everything. This is just the latest version of my attempts. What am I doing wrong?
UPDATE:
Alright, so I found out the metadata isn't saving. I'm not exactly sure why, but I tried fixing it, and it's not working. My fixes made it worse. Here is my code:
`
public function save_metabox( $post_id, $post ) {
// Check if it's not an autosave.
if ( wp_is_post_autosave( $post_id ) )
return;
// Sanitize user input.
$project_new_web_design = isset( $_POST[ 'project_web_design' ] ) ? 'checked' : '';
$project_new_web_development = isset( $_POST[ 'project_web_development' ] ) ? 'checked' : '';
$project_new_digital_art = isset( $_POST[ 'project_digital_art' ] ) ? 'checked' : '';
$project_new_graphic_design = isset( $_POST[ 'project_graphic_design' ] ) ? 'checked' : '';
// Update the meta field in the database.
update_post_meta( $post_id, 'project_web_design ', $project_new_web_design );
update_post_meta( $post_id, 'project_web_development ', $project_new_web_development );
update_post_meta( $post_id, 'project_digital_art ', $project_new_digital_art );
update_post_meta( $post_id, 'project_graphic_design ', $project_new_graphic_design );
}
}

Answer 1

I believe the issue you're having is on this line:
echo '<p>' . get_post_meta( get_the_ID($post->id , 'project_metabox', false) ) . '</p>';
You seem to have mixed get_the_ID and $post->ID together. You're also attempting to echo an array.
The third parameter of get_post_meta will determine whether the value returned is a string or an array. Use true to return a single value.
Change it to:
echo '<p>' . get_post_meta( get_the_ID(), 'project_metabox', true ) . '</p>';
On a minor note you're trying to echo functions like the_excerpt(). You'll typically find that functions starting the_ instead of get_the_ will output directly instead of returning a value. Furthermore the_excerpt() will automatically add paragraph tags.
Replace this:
echo '<p>' . the_excerpt() . '</p>';
With this:
the_excerpt();