Using custom template file in your drupal module

Recently we released Accordion blocks module in drupal. This module should work with all standard drupal modules, otherwise this module is not useful. So to make it work with all themes, I decided to use my custom block.tpl.php which is there in my module. But by default drupal will load block.tpl.php from your theme. If there is not block.tpl.php in the theme then it will load block.tpl.php from the block module.

I used hook_theme_registry_alter() hook to load block.tpl.php from my module. I wrote my hook like this.

function example_module_theme_registry_alter(&$theme_registry) {
// using our own block.tpl.php file.
$theme_registry['block']['template'] = 'block';
$theme_registry['block']['path'] = drupal_get_path('module', 'example_module');
$theme_registry['block']['type'] = 'module';
$theme_registry['block']['theme path'] = drupal_get_path('module', 'example_module');
$theme_registry['block']['theme paths'] = Array();
}

Now after enabling my module every time block.tpl.php from my module is loading. This way we no need to alter any template file in the theme folder. This method only works for drupal6-7

update1: We can over write the theme function also. To over write theme function write theme registry alter hook like this.

function example_module_theme_registry_alter(&$theme_registry) {
// using our own block.tpl.php file.
$theme_registry['block']['function'] = 'theme_custblock'; // your custom theme function name
$theme_registry['block']['path'] = drupal_get_path('module', 'example_module');
$theme_registry['block']['type'] = 'module';
$theme_registry['block']['theme path'] = drupal_get_path('module', 'example_module');
$theme_registry['block']['theme paths'] = Array();
}