Can I create a Drupal autocomplete textfield in a block? - drupal-7

Question

I want to create an auto-complete form in my custom module that will be loaded in a block. Drupal doesn't seem to be loading the necessary Javascript libraries to work properly. How do I know what needs to be loaded and how/where do I tell Drupal to load these libraries?
hook_block_view:
function my_module_block_view($delta = '') {
//The $delta parameter tells us which block is being reqested.
switch ($delta) {
case 'my_module_my_block':
$block['subject'] = t('Block Subject');
$block['content'] = drupal_get_form('my_module_my_form');
break;
}
return $block;
}
Form code:
function my_module_my_form($form, &$form_state) {
$form = array();
$form['term'] = array(
'#type' => 'textfield',
'#autocomplete_path' => 'my-module-autocomplete'
);
$form['submit'] = array(
'#type' => 'submit',
'#value' => 'Add',
);
return $form;
}
The form loads, the field is there, but auto-complete isn't working :(
If I call the my-module-autocomplete path I do get a valid response back when compared with a Content Type edit form. The ajax spinner in the input field never appears so the ajax isn't being called. Realistically all I want is the autocomplete field...the submit will be handled manually.

Answer 1

It's probably because you're reseting $form to an empty array at the beginning of the function. In Drupal 7 there's a bunch of stuff added to that element before it's passed through to your form function (that's why $form is passed to your function whereas in Drupal 6 it wasn't).
Just remove $form = array(); and it should work, other than that your code looks perfect.

Answer 2

the following should work;
function mymodule_block_info() {
$blocks['mymodule'] = array(
// The name that will appear in the block list.
'info' => t('My Module'),
// Default setting.
'cache' => DRUPAL_NO_CACHE,
);
return $blocks;
}
function mymodule_block_view($delta = ''){
switch($delta){
case 'mymodule':
if(user_access('access content')){ //good idea to check user perms here
$block['subject'] = t('My Module');
$block['content'] = 'Hi :)';
$block['content'] = drupal_get_form('mymodule_form');
return $block;
}
break;
}
}
function mydmodule_menu() {
$items['module/autocomplete'] = array(
'page callback' => 'mymodule_autocomplete',
'access arguments' => array('access content'),
'type' => MENU_CALLBACK
);
return $items;
}
function mymodule_form($form, &$form_state) {
$form['greenentry'] = array(
'#type' => 'textfield',
'#title' => t('Enter'),
'#autocomplete_path' => 'mymodule/autocomplete',
);
$form['submit'] = array(
'#type' => 'submit',
'#value' => t('Submit'),
);
return $form;
}
function mymodule_autocomplete($string) {
$matches = array();
// Some fantasy DB table which holds cities
$query = db_select('cities', 'c');
// Select rows that match the string
$return = $query
->fields('c', array('city'))
->condition('c.city', '%' . db_like($string) . '%', 'LIKE')
->range(0, 10)
->execute();
// add matches to $matches
foreach ($return as $row) {
$matches[$row->url] = check_plain($row->url);
}
// return for JS
drupal_json_output($matches);
}

Answer 3

this code is so pretty to add an auto-complete filed in block. But i just found a tiny notice here. if someone get an error
An ajax error occurred. http result code 200
then just add
exit();
after the line
drupal_json_output($matches);
hence fix the issue.