Issue in odoo 8 displaying warning message

Question

I am trying to validate a "capacity" field with onchange decorator but for some reason when I send the warning message the previous line stops working. The template updates the field fine whitout the warning

@api.onchange('capacity')
def check_capacity_values(self):
    if self.capacity<0:
        self.capacity=0
        raise Warning(_('wrong capacity.'))

Answer 1

You can use a dictionary as return value for methods decorated by api.onchange. The key for warning messages will be warning and the value another dictionary with keys title and message. An example:

return {
    'warning': {'title': "WARNING!",
                'message': "It isn't allowed to have a negative capacity!"}
}