Create a custom Content Entity on drupal 8 (Full)

This is a full Example of the Entity 'Vehicle' with user interfaces for:

- Actions (Create, Edit, Delete)

- Listing builder

- Entity settings pages

   - Manage fields

   - Manage form display

   - Manage display

Few tips

Read values of an entity

Here : $this = The entity.

Get a field value:

$this->get('fieldname')->value

Get an entity from entity_reference field:

$this->get('entity_field_name')->entity;

Get entity id from entity_reference field:

$quote->get('entity_field_name')->entity->id()

OR

//$this->getEntityKey('entity_field_name'); //Not tested

File Field (Example)

    $fields['fid'] = BaseFieldDefinition::create('file')

      ->setLabel(t('Photo (fid)'))

      ->setDescription(t('The photo'))

      ->setSetting('target_type', 'file')

      ->setSetting('file_extensions', 'jpg jpeg')

      ->setSetting('file_directory', 'images/myphotosdir')

      ->setSetting('max_filesize', 1024*1024)

      ->setDisplayOptions('view', array(

        'type' => 'file', 'weight' => -8,

      ))

      ->setDisplayOptions('form', array(

        'type' => 'file', 'weight' => -8,

      ))

      ->setDisplayConfigurable('form', TRUE)

      ->setDisplayConfigurable('view', TRUE)

      ->setReadOnly(TRUE);