purchase_add_products/wizard/purchase_add_multiple.xml

<?xml version="1.0"?>
<openerp>
    <data>
        <record model="ir.ui.view" id="search_barcode_purchase_view">
            <field name="name">search.barcode.purchase.form</field>
            <field name="model">search.barcode.purchase</field>
            <field name="arch" type="xml">
                <form string="Add Multiple">

                    <group>
                        <field name='product_code' />
                    </group>
                    <group>
                        <field name="products_ids" nolabel='1'>
                          <tree string="Product Variants">
                            <field name="factory_reference"/>
                            <field name="factory_barcode"/>
                            <field name="product_tmpl_id"/>
                            <field name="attribute_value_ids" widget="many2many_tags"/>
                            <!-- <field name="standard_price" string="Precio coste"/> -->
                            <!-- <field name="price" invisible="not context.get('pricelist',False)"/> -->
                            <!-- <field name="uom_id"/> -->
                          </tree>
                        </field>
                    </group>
                <footer>
                    <button name="add_multiple" type="object" class="oe_highlight" string="Aceptar"/>
                </footer>
                </form>
            </field>
        </record>

        <record model="ir.actions.act_window" id="action_purchase_add_multiple">
            <field name="name">Purchase Order Add Multiple</field>
            <field name="res_model">search.barcode.purchase</field>
            <field name="view_type">form</field>
            <field name="view_mode">form</field>
            <field name="view_id" ref="search_barcode_purchase_view"/>
            <field name="target">new</field>
        </record>
    </data>
</openerp>