Why is a custom field I programmatically created shown as disabled? [closed]

Question

I created a Drupal 8 module for creating a custom field. I wrote the code basing on the documentation given in Create a custom field widget, Create a custom field formatter, and Create a custom field type.

I created the .info.yml file, three directories src/Plugin/Field (FieldFormatter, FieldType, and FieldWidget) where I put the files described in those documentation guides.
I could see the custom field in the field list, but it is shown as disabled.

Why does this happen?

Answer 1

I had the same problem and the issue in my case was that I was using default_widget = "options_select" in my FieldType plugin but the options_select widget does not allow my custom field type.

The solution was to create a custom FieldWidget plugin which extends the OptionsSelectWidget and in the field_types declare my custom field type.

This allowed my field to be placed in the form correctly and the options widget to be used.

Answer 2

After the field is created and the field instance is added, you need to enable the field in the display settings for the form, for example with the following code.

entity_get_form_display('node', $bundle, 'default')
  ->setComponent('field_custom', array(
    'type' => 'string'
  ))
  ->save();