Checkbox in post not saving value

Question

Change,

echo '<input type="checkbox" id="movie_abc" name="movie_abc" value="true" />';

to…

echo '<input type="checkbox" id="movie_abc" name="movie_abc" value="1"' . checked( $mydata , 1 ) . '/>';

…and let us know how you go.

Update

Try the following,

echo '<input type="checkbox" id="movie_abc" name="movie_abc" value="1"', $mydata ? ' checked="checked"' : '', '/>';

Update 2

This is a duplicate question;

I now see in your code that you are not updating the meta_key values for,

movie_abc and movie_xyz

So you need to add,

update_post_meta($post_id, 'movie_abc', $mydata); //current value of this key is "true" only?
update_post_meta($post_id, 'movie_xyz', $mydata);

…to your save_postdata() function.

Update 3

$mydata = get_post_meta($post->ID, 'movie', TRUE);
if($mydata  == true)
$checked  = 'checked="checked"'; 
echo '<input type="checkbox" id="movie_abc" name="movie_abc" value=""', $checked, '/>';