Added config for turn on/off display mode (grid and list)

advanced_search.module

@@ -118,7 +118,9 @@ function advanced_search_preprocess_views_view(&$variables) {
   // has been created for.
   if (in_array([$view->id(), $view->current_display], $views)) {
     // Toggle between 'list' and 'grid' display depending on url parameter.
-    $format = \Drupal::request()->query->get('display') ?? 'grid';
+    $config = \Drupal::config(SettingsForm::CONFIG_NAME);
+    
+    $format = \Drupal::request()->query->get('display') ?? $config->get(SettingsForm::DISPLAY_DEFAULT);
     $variables['attributes']['class'][] = "view-{$format}";
     $view->element['#attached']['library'][] = 'advanced_search/advanced.search.pager';
   }

src/Form/SettingsForm.php

@@ -25,6 +25,9 @@ class SettingsForm extends ConfigFormBase {
   const EDISMAX_SEARCH_FLAG = 'lucene_on_off';
   const EDISMAX_SEARCH_LABEL = 'lucene_label';
   const SEARCH_ALL_FIELDS_FLAG = 'all_fields_on_off';
+  const DISPLAY_LIST_FLAG = 'list_on_off';
+  const DISPLAY_GRID_FLAG = 'grid_on_off';
+  const DISPLAY_DEFAULT = 'default-display-mode';
   
   /**
    * Constructs a \Drupal\system\ConfigFormBase object.
@@ -105,6 +108,36 @@ class SettingsForm extends ConfigFormBase {
       ],
     ];
 
+    $form['display-mode'] =  [
+      '#type' => 'fieldset',
+      '#title' => $this->t("Display Mode"),
+    ];
+    
+    $form['display-mode'][self::DISPLAY_LIST_FLAG] = [
+      '#type' => 'checkbox',
+      '#title' => $this
+        ->t('Enable List View.'),
+      '#default_value' => self::getConfig(self::DISPLAY_LIST_FLAG, 0),
+    ];
+
+    $form['display-mode'][self::DISPLAY_GRID_FLAG] = [
+      '#type' => 'checkbox',
+      '#title' => $this
+        ->t('Enable Grid View.'),
+      '#default_value' => self::getConfig(self::DISPLAY_GRID_FLAG, 0),
+    ];
+
+    $form['display-mode'][self::DISPLAY_DEFAULT] = [
+      '#type' => 'select',
+      '#title' => $this
+        ->t('Default display mode:'),
+      '#options' => [
+        'list' => 'List',
+        'grid' => 'Grid'
+      ],
+      '#default_value' => self::getConfig(self::DISPLAY_DEFAULT, 'grid'),
+    ];
+
     $form['edismax'] =  [
       '#type' => 'fieldset',
       '#title' => $this->t("Extended DisMax Query"),
@@ -160,6 +193,9 @@ class SettingsForm extends ConfigFormBase {
       ->set(self::EDISMAX_SEARCH_FLAG, $form_state->getValue(self::EDISMAX_SEARCH_FLAG))
       ->set(self::EDISMAX_SEARCH_LABEL, $form_state->getValue(self::EDISMAX_SEARCH_LABEL))
       ->set(self::SEARCH_ALL_FIELDS_FLAG, $form_state->getValue(self::SEARCH_ALL_FIELDS_FLAG))
+      ->set(self::DISPLAY_LIST_FLAG, $form_state->getValue(self::DISPLAY_LIST_FLAG))
+      ->set(self::DISPLAY_GRID_FLAG, $form_state->getValue(self::DISPLAY_GRID_FLAG))
+      ->set(self::DISPLAY_DEFAULT, $form_state->getValue(self::DISPLAY_DEFAULT))
       ->save();
     parent::submitForm($form, $form_state);
   }

src/Plugin/Block/SearchResultsPagerBlock.php

@@ -12,6 +12,7 @@ use Drupal\views\Plugin\views\pager\SqlBase;
 use Drupal\views\ViewExecutable;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
+use Drupal\advanced_search\Form\SettingsForm;
 
 /**
  * Provides a 'AjaxViewBlock' block.
@@ -212,17 +213,24 @@ class SearchResultsPagerBlock extends BlockBase implements ContainerFactoryPlugi
    *   A renderable array representing the display links portion of pager.
    */
   protected function buildDisplayLinks(array $query_parameters) {
-    $active_display = $query_parameters['display'] ?? 'grid';
-    $display_options = [
-      'list' => [
+    $config = \Drupal::config(SettingsForm::CONFIG_NAME);
+    $display_options = [];
+    
+    if ($config->get(SettingsForm::DISPLAY_LIST_FLAG) == 1) { 
+      $display_options['list'] = [
         'icon' => 'fa-list',
         'title' => $this->t('List'),
-      ],
-      'grid' => [
+      ];
+    }
+
+    if ($config->get(SettingsForm::DISPLAY_GRID_FLAG) ==1) { 
+      $display_options['grid'] = [
         'icon' => 'fa-th',
-        'title' => $this->t('Grid'),
-      ],
-    ];
+        'title' => $this->t('Grid')
+      ];
+    }
+
+    $active_display = $query_parameters['display'] ?? $config->get(SettingsForm::DISPLAY_DEFAULT);
     $items = [];
     foreach ($display_options as $display => $options) {
       $url = Url::fromRoute('<current>', [], [