carrier_file_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record id="view_delivery_carrier_file_form_document" model="ir.ui.view">
            <field name="name">delivery.carrier.file.form</field>
            <field name="model">delivery.carrier.file</field>
            <field name="inherit_id" ref="base_delivery_carrier_files.view_delivery_carrier_file_form"/>
            <field name="arch" type="xml">
                <data>
                    <field name="export_path" position="after">
                        <field name="document_directory_id" attrs="{'required': [('write_mode', '=', 'document')], 'invisible': [('write_mode', '!=', 'document')]}"/>
                    </field>
                </data>
            </field>
        </record>
    </data>
</openerp>