Odoo 12 Development Essentials - Fourth Edition

On change methods

The on change methods are triggered from user interface form views, when the user edits a value on a particular field to perform some business logic immediately. This can be performing some validation, showing a message to the user, or changing other fields in form. The model method supporting this logic should be decorated with @api.onchange('fld1', 'fld2', ...). The decorator arguments are the names of the fields that will trigger the method when edited by the user.

A particular form disables the on change behavior, by adding the field attribute on_change="0", for example, <field name="fld1" onchange="0" />.

Inside the method, the self argument is a virtual record with the current form data. If values are set on the record, ...