Correct way to render an custom entity and its custom field?

Question

In my module, I have a custom entity LocationEntity and it uses a custom field type CoordinateItem which has 2 sub fields X, Y.

So what is the correct way of Drupal 8 to:

1) Render this LocationEntity in a twig template?

• What I'm doing is just send the entity to twig template '#loc1' and manually render its each field value using getter method {{ loc1.getName() }}. It works but I'm sure this is not the correct way to do.

2) If question 1 has another correct way then how to have more than one templates for rendering the entity?

• For example, one simple layout with less fields and one detail layout with all fields.

3) In the entity, I defined to use the custom field CoordinateItem. But now what to do with its getter and setter, because it's not a single sub field inside?

• Getter if $this->get('coord') -> a FieldItemList object.
• Getter if $this->get('coord')->value -> null.
• Setter? What type is the parameter?

4) I wrote a formatter for CoordinateItem to show its sub fields. But again I don't know how to use this formatter to render this custom field in the main (entity) template?

• Maybe this is related to question 1 and 2?

Answer 1

View Builder

• 1. Set the view_builder in ContentEntityType annotation to EntityViewBuilder to inherit some default behavior (or write your own).
• 2. Set your canonical router to something like what content_entity_example does in the examples module.
     • Berdir suggests using DefaultHtmlRouteProvider though that class is marked as @internal so it may not be stable to use long term.

content_entity_example.routing.yml

entity.content_entity_example_contact.canonical:
  path: '/content_entity_example_contact/{content_entity_example_contact}'
  defaults:
    _entity_view: 'content_entity_example_contact'
    _title: 'Contact Content'
  requirements:
    _entity_access: 'content_entity_example_contact.view'

• 3. Change your entity theme to something like what node module does, and have it display as a render element.
• 4. Use your entity or bundle's field display page to change what field formatters a given field will use.
• 5. Then you can print out {{ elements }} in the template for it to go through the entire render array for a given view mode. Again, you can follow something similar to node module.