Onchange triggered only once

Question

In sale.order I made the field and I want when SO state changes this field will fill up based on current UID

the problem onchange is triggered only once when I create SO, but when I confirm it, ocnahnge is not triggered.

What do I miss about onchange ?

user_prepared = fields.Many2one('res.users', string="Prepared offer")

        @api.onchange('state')
        def _onchange_state(self):
             self.user_prepared = self._uid

Answer 1

You can use @api.depends('state') this will call method whever state fields value change

    @api.depends('state')
    def _onchange_state(self):
         self.user_prepared = self._uid