I need to add Quantity field to journal items , the value of this field will be the same value of Done field of stock move , and if the journal entry created without stock move the value of Quantity field will be 1.

I created this code :

class AccountMove(models.Model):
    _inherit = 'account.move.line'

    qty=fields.Float(string="QTY",default=1)

and this code on xml:

<?xml version="1.0"?>
<odoo>

    <record id="view_move_inherit" model="ir\.ui\.view"\>
\ />\ \ \ \ \ \ \ \ \<field\ name="name"\>view\.move\.inherit\</field\>
\ />\ \ \ \ \ \ \ \ \<field\ name="model"\>account\.move\</field\>
\ \ \ \ \ \ \ \ \<field\ name="inherit_id"\ ref="account\.view_move_form"/\>
\ \ \ \ \ \ \ \ \<field\ name="arch"\ type="xml"\>
\ \ \ \ \ \ \ \ \ \ \ \ \<xpath\ expr="//notebook/page/field\[@name='line_ids'\]/tree/field\[@name='partner_id'\]"\ position="after"\>
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \<field\ name="qty"/\>
\ \ \ \ \ \ \ \ \ \ \ \ \</xpath\>
\ \ \ \ \ \ \ \ \</field\>
\ \ \ \ \</record\>

\ \ \ \ \<record\ id="view_move_list_inherit"\ model="ir\.ui\.view"\>
\ />\ \ \ \ \ \ \ \ \<field\ name="name"\>view\.move\.list\.inherit\</field\>
\ />\ \ \ \ \ \ \ \ \<field\ name="model"\>account.move.line</field>
 />        <field name="inherit_id" ref="account.view_move_line_tree"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='partner_id']" position="after">
                <field name="qty"/>
            </xpath>
        </field>
    </record>


</odoo>

How can i make the value of Quantity field the same value of done in case of journal entry created by stock move?