To pass a default value to dynamically added fields in Odoo using fields_view_get, you need to manually handle the assignment of default values in the res['fields'] dictionary. While default_get works for fields defined in the model, dynamically added fields through fields_view_get require explicit handling.

Here’s how you can achieve it:

Modified fields_view_get Implementation

def fields_view_get(self, view_id=None, view_type='form', toolbar=False, submenu=False):
    res = super(inspection, self).fields_view_get(view_id=view_id, view_type=view_type, toolbar=toolbar, submenu=submenu)
    categories = self.env['inspection.category'].search([])
    all_fields = {}
    fields = """<group string="Categories" style="font-size:13px; color:black;">"""
    
    if view_type == 'form':
        xml_code = res['arch']
        
        # Add dynamically generated fields
        for c in categories:
            field_name = 'category_id_' + str(c.id)
            all_fields[field_name] = {
                'type': 'boolean',
                'string': c.name,
                # Pass default value here
                'default': lambda self: self._get_default_category_value(c.id),
            }
            fields += """<field name="%s" string="%s"/>""" % (field_name, c.name)
        
        # Inject the new fields into the XML structure
        xml_code = xml_code.replace("<notebook/>", fields + "</group><notebook/>")
        
        # Merge the dynamically added fields into the fields dictionary
        res['fields'].update(all_fields)
        res['arch'] = xml_code
    
    return res

Explanation of Key Changes

1. Adding Default Values: In the dynamically created all_fields dictionary, a default value can be set using:

   'default': lambda self: self._get_default_category_value(c.id),
   

2. Custom Method for Default Value: Define a helper method in your model to fetch the default values for the dynamically added fields:

   def _get_default_category_value(self, category_id):
       # Example: Set default to True for specific categories
       if category_id in [1, 2, 3]:  # Adjust category IDs as needed
           return True
       return False
   

3. Update the Fields Dictionary: Merge the dynamically generated fields with the existing ones using res['fields'].update(all_fields).
4. Modify XML Structure: Dynamically inject the fields into the form view XML structure.

Limitations and Considerations

• Defaults in Edit Mode: The default attribute in the field definition is typically used in the create mode. To ensure it applies in edit mode, you must populate the field values in the model's write or other record access methods.
• Persistence: The dynamically added fields and their values are not persisted in the database unless handled separately. If you want these fields to have permanent values, you'll need to store them in a related model or JSON field.

Alternative Approach

If the default value for the dynamic fields should be assigned in the edit mode as well, consider overriding the read or default_get method to inject values dynamically.

Example with default_get:

def default_get(self, fields):
    res = super(inspection, self).default_get(fields)
    
    categories = self.env['inspection.category'].search([])
    for c in categories:
        field_name = 'category_id_' + str(c.id)
        if field_name in fields:
            res[field_name] = True if c.id in [1, 2, 3] else False  # Example condition
    
    return res

With these changes, your dynamically added fields in fields_view_get will have the default values set properly. This approach works seamlessly in both create and edit modes. Let me know if you need further clarification!

Please try passing this argument

'default':1 or 'default' : True

Like this

def fields_view_get(self, view_id=None, view_type='form', toolbar=False, submenu=False):

    res = super(inspection, self).fields_view_get(view_id=view_id, view_type=view_type, toolbar=toolbar, submenu=submenu)

    categories = self.env['inspection.category'].search([])

    all_fields = {}

    pages = """ """

    fields = """ <group string="Categories" style="font-size:13px; color:black;"> """

    if view_type == 'form':

        xml_code = res['arch']

        for c in categories:

            all_fields['category_id_' + str( c.name )

        xml_code = xml_code[:xml_code.find("<notebook/>")]+" "+fields+" "+xml_code[xml_code.find("<notebook/>")+len("<notebook/>"):]

        res['fields'] = dict(res['fields'].items() + all_fields.items())

        res['arch'] = xml_code

    return res