La magie consiste à utiliser la propriété #ahah / #ajax avec des éléments de formulaire, de cette façon, vous pouvez définir ce qui doit déclencher la modification et ce qui doit être modifié en conséquence, en plus il s'intègre parfaitement avec jQuery.
C'est la partie importante de l'exemple ci-dessous:
'#ajax' => array(
'event' => 'change',
'callback' => 'myajax_ajax_callback',
'wrapper' => 'dropdown_second_replace',
),
Voici un exemple qui montre une page basée sur un formulaire avec deux listes déroulantes: la liste des options dans la deuxième liste déroulante dépend de la sélection dans la première liste déroulante.
<?php
/**
* Implementation of hook_menu().
* Registers a form-based page that you can access at "http://localhost/myajax"
*/
function myajax_menu(){
return array(
'myajax' => array(
'title' => 'A page to test ajax',
'page callback' => 'drupal_get_form',
'page arguments' => array('myajax_page'),
'access arguments' => array('access content'),
)
);
}
/**
* A form with a dropdown whose options are dependent on a
* choice made in a previous dropdown.
*
* On changing the first dropdown, the options in the second are updated.
*/
function myajax_page($form, &$form_state) {
// Get the list of options to populate the first dropdown.
$options_first = myajax_first_dropdown_options();
// If we have a value for the first dropdown from $form_state['values'] we use
// this both as the default value for the first dropdown and also as a
// parameter to pass to the function that retrieves the options for the
// second dropdown.
$value_dropdown_first = isset($form_state['values']['dropdown_first']) ? $form_state['values']['dropdown_first'] : key($options_first);
$form['dropdown_first'] = array(
'#type' => 'select',
'#title' => 'First Dropdown',
'#options' => $options_first,
'#default_value' => $value_dropdown_first,
// Bind an ajax callback to the change event (which is the default for the
// select form type) of the first dropdown. It will replace the second
// dropdown when rebuilt
'#ajax' => array(
// When 'event' occurs, Drupal will perform an ajax request in the
// background. Usually the default value is sufficient (eg. change for
// select elements), but valid values include any jQuery event,
// most notably 'mousedown', 'blur', and 'submit'.
'event' => 'change',
'callback' => 'myajax_ajax_callback',
'wrapper' => 'dropdown_second_replace',
),
);
$form['dropdown_second'] = array(
'#type' => 'select',
'#title' => 'Second Dropdown',
// The entire enclosing div created here gets replaced when dropdown_first
// is changed.
'#prefix' => '<div id="dropdown_second_replace">',
'#suffix' => '</div>',
// when the form is rebuilt during ajax processing, the $value_dropdown_first variable
// will now have the new value and so the options will change
'#options' => myajax_second_dropdown_options($value_dropdown_first),
'#default_value' => isset($form_state['values']['dropdown_second']) ? $form_state['values']['dropdown_second'] : '',
);
return $form;
}
/**
* Selects just the second dropdown to be returned for re-rendering
*
* Since the controlling logic for populating the form is in the form builder
* function, all we do here is select the element and return it to be updated.
*
* @return renderable array (the second dropdown)
*/
function myajax_ajax_callback($form, $form_state) {
return $form['dropdown_second'];
}
/**
* Helper function to populate the first dropdown. This would normally be
* pulling data from the database.
*
* @return array of options
*/
function myajax_first_dropdown_options() {
return array(
'colors' => 'Names of colors',
'cities' => 'Names of cities',
'animals' => 'Names of animals',
);
}
/**
* Helper function to populate the second dropdown. This would normally be
* pulling data from the database.
*
* @param key. This will determine which set of options is returned.
*
* @return array of options
*/
function myajax_second_dropdown_options($key = '') {
$options = array(
'colors' => array(
'red' => 'Red',
'green' => 'Green',
'blue' => 'Blue'
),
'cities' => array(
'paris' => 'Paris, France',
'tokyo' => 'Tokyo, Japan',
'newyork' => 'New York, US'
),
'animals' => array(
'dog' => 'Dog',
'cat' => 'Cat',
'bird' => 'Bird'
),
);
if (isset($options[$key])) {
return $options[$key];
}
else {
return array();
}
}