How to get parent values in default_get function? In Odoo 9

Question

I want to create a new register, but I need to put the value of a parent field as a default value of a child field.

I read that you can send parent values through context from XML and whenever a new form is opened, "default_get" of that object will be executed.

My questions are:

1. How can I pass the parent values to the child?
2. How can I access to those values in the default_get method?

I have tried this:

In XML view:

<field name="my_child_field" context="{'variable1': parent}"/>

In .py file:

@api.model
def default_get(self, vals):
    context = dict(self.env.context)
    variable1 = context.get('variable1', False)
    print ' variable1'

That prints False as variable1 value.

Answer 1

Let me assume you have the following constellation:

class MyParent(models.Model):
    _name = "my.parent"

    child_ids = fields.One2many(
        comodel_name="my.child", inverse_name="parent_id")
    my_default_for_child = fields.Char()

class MyChild(models.Model):
    _name = "my.child"

    parent_id = fields.Many2one(comodel_name="my.parent")
    my_field_for_default = fields.Char()

And of course a view definition. Just put the default value in the context, no need to use or extend default_get():

<record id="my_parent_form_view" model="my.parent">
    <field name="name">my.parent.form.view</field>
    <field name="model">my.parent</field>
    <field name="arch" type="xml">
        <form>
            <field name="my_default_for_child" />
            <field name="child_ids"
                context="{'default_my_field_for_default': my_default_for_child}">
                <tree editable="bottom">
                    <field name="parent_id" invisible="1" />
                    <field name="my_field_for_default" />
                </tree>
            </field>
        </form>
    </field>
</record>