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How to use the Form Radios

Custom forms sometimes need to include radio buttons, to create a selection option with few options.

Code Snippet

$form['settings']['active'] = [
    '#type' => 'radios',
    '#title' => $this->t('Poll status'),
    '#default_value' => 1,
    '#options' => [
        0 => $this->t('Closed'),
        1 => $this->t('Active'),
    ],
]

Drupal Resources and Reference

This article is a collection of important links and resources for drupal beginners and drupal experts

It will include reference resources, links, images, and even media.

Please comment with every important link.

Select Element, its more hard to deal with Ajax

Drupal Form Select element is harder to deal with when desired to add to it Ajax activities

Ajax is a bit misleading, it's not all on the client side, and if we still want to handle it from the code which is located on the server, e/s program it with the form objects like $form & $form_state it still needs to update the server side within the flow, and the form is still need to have synchronization transactions between the client, server, and cache

not enough documentation on that, especially when working with specific elements like SELECT

Code Snippet

    public function buildForm(array $form, FormStateInterface $form_state, $dashboard = 0, $project=0, $sprint=0, $redirect='') {  //
      $config = \Drupal::config('drupalvip_task.settings');
      $log = $config->get('log');
      ($log)? \Drupal::logger("drupalvip_task")->debug(__FUNCTION__ . ": START "):'';      
      ($log)? \Drupal::logger("drupalvip_task")->debug("Form Args: da[$dashboard] pr[$project] sp[$sprint] rd[$redirect]"):'';
      
      $form['redirect'] = array(
          '#type' => 'value',
          '#value' => $redirect,
      );
      
      //dashboard select
      $dashboard_default = ($dashboard==0) ? null : $dashboard;
      $dashboard_options = DashboardController::getDashboards();
      $form['dashboard_select'] = [
        '#type' => 'select',
        '#title' => t('Dashboard'),
        //'#name' => 'dashboard-select',  <-- prevent the form_state to update
        '#options' => $dashboard_options,
        '#sort_options' => TRUE,
        '#required' => TRUE,
        '#empty_option' => "-- SELECT --",
        '#size' => 1,
        '#default_value' => $dashboard_default,
        '#attributes' => [
          'class' => ['use-ajax'],
          //'id' => "edit-dashboard-select", <-- this prevent the callback
        ],         
        '#ajax' => [
          'callback' => '::submitFormDashboardSelected',
          'wrapper' => 'group-select-wrapper',
          'suppress_required_fields_validation' => TRUE,
        ],        
      ];      
      
      $form['group'] = [
        '#type' => 'fieldgroup',
        '#prefix' => '<div id="group-select-wrapper">',
        '#suffix' => '</div>',         
      ];      
        $options[0] = "-- select --";        
        $form['group']['project_select'] = [
          '#type' => 'select',
          '#title' => $this->t('Project'),
          '#options' => $options,
          '#limit_validation_errors' => [],
          //'#empty_option' => "-- select --",
          '#size' => 1,        
          '#default_value' => 0, 
        ]; 
        if ($dashboard > 0) {
          $project_options = DashboardController::getProjects($dashboard);
          $project_options_2 = $options + $project_options ;
          $form['group']['project_select']['#options'] = $project_options_2; //$project_options; 
          $form['group']['project_select']['#default_value'] = $project;
        }      

        $form['group']['sprint_select'] = [
          '#type' => 'select',
          '#title' => $this->t('Sprint'),
          '#options' => $options,
          '#limit_validation_errors' => [],
          //'#empty_option' => "-- select --",
          '#size' => 1,        
          '#default_value' => 0, 
        ]; 
        if ($dashboard > 0) {
          $sprint_options = DashboardController::getSprints($dashboard);
          $sprint_options_2 = $options + $sprint_options ;
          $form['group']['sprint_select']['#options'] = $sprint_options_2; 
          $form['group']['sprint_select']['#default_value'] = $sprint;
        }      
        
      $form['subject'] =  [
        '#type' => 'textfield',
        '#title' => $this->t('Subject'),
        '#required' => TRUE,
        '#attributes' => [
          //'id' => "task-subject-box",
        ],        
      ];
      
      $form['actions'] = [
        '#type' => 'actions',
        '#attributes' => [
          'class' => ['form_actions'],
        ],         
      ];
        $form['actions']['cancel'] = [
          '#type' => 'submit',
          '#value' => $this->t('Cancel'),
          '#attributes' => [
            'class' => ['button','use-ajax','form-submit-modal','action-cancel' ],
          ],
          '#ajax' => [
            'callback' => [$this, 'submitFormClose'],
            'event' => 'click',
          ],
        ];       
        $form['actions']['create'] = [
          '#type' => 'submit',
          '#value' => $this->t('Create'),
          '#attributes' => [
            'class' => ['button','use-ajax','form-submit-modal','action-create' ],
          ],
          '#ajax' => [
            'callback' => [$this, 'submitFormCreate'],
            'event' => 'click',
            'onclick' => 'javascript:var s=this;setTimeout(function(){s.value="Saving...";s.disabled=true;},1);',
          ],
        ];              

      $form['#attributes']['class'][] = 'drupalvip_form';  
      $form['#attached']['library'][] = 'drupalvip_task/content';
      $form['#attached']['library'][] = 'core/drupal.dialog.ajax';
      $form['#attached']['library'][] = 'core/drupal.ajax';
      $form['#attached']['library'][] = 'core/jquery.form';
      
      ($log)? \Drupal::logger("drupalvip_task")->debug(__FUNCTION__ . ": RETURN FORM "):'';
      return $form;    
    }

How to create a "go back" or "cancel" button on the node add form?

sometimes you only need a 'cancel' button that will do an undo to just close the popup window

Form Element 'table' with TableDrag and TableSelect

Building and rendering a table required writing a custom/dedicated theme function for most tables in Drupal 7.

Drupal 8 introduces a new element '#type' => 'table', which comes with built-in, optional support for TableDrag and TableSelect, and which requires no more custom plumbing for most use-cases.

Note: The following conversion example shows both TableDrag and TableSelect in a single table for brevity, but they are usually not combined in a single table.

Render-Element and Form-Element

Form elements are a subset of render elements, representing elements for HTML forms, which can be referenced in form arrays.
See the Render API topic for an overview of render arrays and render elements, and the Form API topic for an overview of forms and form arrays.

Drupal Form Element Reference

Drupal core provides a couple dozen different input #type elements that can be added to forms. This includes one for every standard HTML5 input element, and some Drupal-specific ones that encapsulate more complex interactions like uploading files. But how can you know what elements exist? Where do you find information about what Render API properties each element uses?

How to change an existing Drupal form

Changing an existing form is one of the first things that new Drupal developers will learn how to do.

It is a natural extension from site building, where you might need to change one thing on a form created by a core or contributed module.

One of the benefits of using the Form API to construct forms is that any module can alter any other module's form.

In this tutorial, you are going to learn how to alter a Drupal form.

Render API overview and Render Element

The main purpose of Drupal's Theme system is to give themes complete control over the appearance of the site, which includes the markup returned from HTTP requests and the CSS files used to style that markup.
In order to ensure that a theme can completely customize the markup, module developers should avoid directly writing HTML markup for pages, blocks, and other user-visible output in their modules, and instead return structured "render arrays" (see Render arrays below).