#2746713 - Multiple choice poll

Closes #2746713

src/Entity/Poll.php

@@ -212,6 +212,14 @@ class Poll extends ContentEntityBase implements EntityPublishedInterface, PollIn
     return $this;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getAnswerType(): string {
+    $answer_type = $this->get('answer_type')->value;
+    return empty($answer_type) ? PollInterface::ANSWER_TYPE_SINGLE : $answer_type;
+  }
+
   /**
    * {@inheritdoc}
    */
@@ -349,6 +357,23 @@ class Poll extends ContentEntityBase implements EntityPublishedInterface, PollIn
       ])
       ->setDisplayConfigurable('form', TRUE);
 
+    $fields['answer_type'] = BaseFieldDefinition::create('list_string')
+      ->setLabel(t('Answer Type'))
+      ->setDescription(t('Choose if user can select single or multiple answers.'))
+      ->setSetting('allowed_values', [
+        PollInterface::ANSWER_TYPE_SINGLE => t('Single Answer'),
+        PollInterface::ANSWER_TYPE_MULTIPLE => t('Multiple Answers'),
+      ])
+      ->setDefaultValue(PollInterface::ANSWER_TYPE_SINGLE)
+      ->setRequired(TRUE)
+      ->setDisplayOptions('form', [
+        'type' => 'options_select',
+        'settings' => [
+          'display_label' => TRUE,
+        ],
+        'weight' => 1,
+      ]);
+
     $fields['anonymous_vote_allow'] = BaseFieldDefinition::create('boolean')
       ->setLabel(t('Allow anonymous votes'))
       ->setDescription(t('A flag indicating whether anonymous users are allowed to vote.'))