Get the value from module to template

Question

I want to pass the value from module to page tpl file in drupal.I have created a custom module 'one_time_popup'.I have created a sample soutput and tried to pass it and print in page.tpl.php after footer section.but doesn't shows any thing.What I did wrong.I'm a newbie

function one_time_popup_menu(){
$items['oneTimePopupData'] = array(
'title' => 'One time Popup',
'page callback' => 'one_time_popup_user_login',
'type' => MENU_CALLBACK,
'access callback' => TRUE,
);
return $items;
}
function one_time_popup_user_login(&$edit, $account){
 ...
$output='value from one time popup module!';
return theme('photo_order',array('results' => $output));
} 
function one_time_popup_theme() {
 return array(
'photo_order' => array(
  'template' => 'page',
  'variables' => array(
    'results' => NULL,
  ),
 ),
 ); 
}

Tpl file(page.tpl)
<?php echo $results; ?>

Answer 1

<?php
/**
 * Implements hook_menu()
 */
function mymodule_menu() {
  $items = array(
      'custom_menu_item' => array(
        'title' => 'Hello world',
        'page callback' => '_page_hello_world',
        'access callback' => TRUE,
      ),
    );
  return $items;
}

/**
 * Implements hook_theme().
 */
function mymodule_theme() {
  $theme = array();
  $theme['mymodule_template'] = array(
    'template' => 'mymodule-template',
  );
  return $theme;
}

/**
 * Preprocessor function for 'mymodule_template'.
 */
function template_preprocess_mymodule_template(&$vars) {
  $vars['hello'] = 'hello!';
}

/**
 * Page callback.
 */
function _page_hello_world() {
  return theme('mymodule_template');

}

A $hello variable is available in your template at path /custom_menu_item