Theming Block Contents in Drupal 7

Question

I can change the overall layout of a block editing the block.tpl.php file. I can modify the way subject looks, but what I want to take control over contents of the block which is accessible by single line of code:

<?php print $content ?>

Now, How can I theme contents of the block, i.e. list items etc?

If I've failed to clarify myself, please mention it in your comments. Thanks :)

Answer 1

Before blocks get to the theme layer, they can be altered. Blocks are represented as "render arrays", which means you can manipulate them with the Render API.

You can use hook_block_view_alter() to change the contents of a block.

Any module or theme can implement this hook. For example, a theme named YOURTHEME would have code like this:

function YOURTHEME_block_view_alter(&$data, $block) {
  // Remove the contextual links on all blocks that provide them.
  if (is_array($data['content']) && isset($data['content']['#contextual_links'])) {
    unset($data['content']['#contextual_links']);
  }
  // Add a theme wrapper function defined by the current module to all blocks
  // provided by the "somemodule" module.
  if (is_array($data['content']) && $block->module == 'somemodule') {
    $data['content']['#theme_wrappers'][] = 'mymodule_special_block';
  }
}

Or, if you know in advance the module and delta you'd like to alter, you can use hook_block_view_MODULE_DELTA_alter() like this:

function YOURTHEME_block_view_MODULE_DELTA_alter(&$data, $block) {
  // This code will only run for a specific block. For example, if MODULE_DELTA
  // in the function definition above is set to "mymodule_somedelta", the code
  // will only run on the "somedelta" block provided by the "mymodule" module.

  // Change the title of the "somedelta" block provided by the "mymodule"
  // module.
  $data['subject'] = t('New title of the block');
}

Answer 2

You can use Views to generate a block which you can exactly theme the way you want.

Answer 3

In short, you cannot. $content is the minimal piece of information known to the block module.