class Simplest
Same name in other branches
- 3.x modules/ajax_example/src/Form/Simplest.php \Drupal\ajax_example\Form\Simplest
- 4.0.x modules/ajax_example/src/Form/Simplest.php \Drupal\ajax_example\Form\Simplest
A relatively simple AJAX demonstration form.
Hierarchy
- class \Drupal\ajax_example\Form\Simplest extends \Drupal\Core\Form\FormBase
Expanded class hierarchy of Simplest
1 string reference to 'Simplest'
- ajax_example.routing.yml in ajax_example/
ajax_example.routing.yml - ajax_example/ajax_example.routing.yml
File
-
ajax_example/
src/ Form/ Simplest.php, line 11
Namespace
Drupal\ajax_example\FormView source
class Simplest extends FormBase {
/**
* {@inheritdoc}
*/
public function getFormId() {
return 'ajax_example_simplest';
}
/**
* {@inheritdoc}
*/
public function buildForm(array $form, FormStateInterface $form_state) {
$form['changethis'] = [
'#title' => $this->t("Choose something and explain why"),
'#type' => 'select',
'#options' => [
'one' => 'one',
'two' => 'two',
'three' => 'three',
],
'#ajax' => [
// #ajax has two required keys: callback and wrapper.
// 'callback' is a function that will be called when this element
// changes.
'callback' => '::promptCallback',
// 'wrapper' is the HTML id of the page element that will be replaced.
'wrapper' => 'replace-textfield-container',
],
];
// The 'replace-textfield-container' container will be replaced whenever
// 'changethis' is updated.
$form['replace_textfield_container'] = [
'#type' => 'container',
'#attributes' => [
'id' => 'replace-textfield-container',
],
];
$form['replace_textfield_container']['replace_textfield'] = [
'#type' => 'textfield',
'#title' => $this->t("Why"),
];
// An AJAX request calls the form builder function for every change.
// We can change how we build the form based on $form_state.
$value = $form_state->getValue('changethis');
// The getValue() method returns NULL by default if the form element does
// not exist. It won't exist yet if we're building it for the first time.
if ($value !== NULL) {
$form['replace_textfield_container']['replace_textfield']['#description'] = $this->t("Say why you chose '@value'", [
'@value' => $value,
]);
}
return $form;
}
/**
* {@inheritdoc}
*/
public function submitForm(array &$form, FormStateInterface $form_state) {
// No-op. Our form doesn't need a submit handler, because the form is never
// submitted. We add the method here so we fulfill FormInterface.
}
/**
* Handles switching the available regions based on the selected theme.
*/
public function promptCallback($form, FormStateInterface $form_state) {
return $form['replace_textfield_container'];
}
}
Members
Title Sort descending | Modifiers | Object type | Summary |
---|---|---|---|
Simplest::buildForm | public | function | |
Simplest::getFormId | public | function | |
Simplest::promptCallback | public | function | Handles switching the available regions based on the selected theme. |
Simplest::submitForm | public | function |