account-closing/account_invoice_start_end_dates/views/account_invoice.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  Copyright 2013-2016 Akretion, Alexis de Lattre <alexis.delattre@akretion.com>
  License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
-->

<flectra>

    <record id="invoice_form" model="ir.ui.view">
        <field name="name">prepaid.cutoff.invoice_form</field>
        <field name="model">account.invoice</field>
        <field name="inherit_id" ref="account.invoice_form" />
        <field name="arch" type="xml">
            <xpath expr="//field[@name='invoice_line_ids']/tree/field[@name='account_analytic_id']" position="after">
                <field name="start_date"
                    attrs="{'required': [('must_have_dates', '=', True)]}"/>
                <field name="end_date"
                    attrs="{'required': [('must_have_dates', '=', True)]}"/>
                <field name="must_have_dates" invisible="1"/>
            </xpath>
        </field>
    </record>

    <record id="invoice_supplier_form" model="ir.ui.view">
        <field name="name">prepaid.cutoff.invoice_supplier_form</field>
        <field name="model">account.invoice</field>
        <field name="inherit_id" ref="account.invoice_supplier_form" />
        <field name="arch" type="xml">
            <xpath expr="//field[@name='invoice_line_ids']/tree/field[@name='account_analytic_id']" position="after">
                <field name="start_date"
                    attrs="{'required': [('must_have_dates', '=', True)]}"/>
                <field name="end_date"
                    attrs="{'required': [('must_have_dates', '=', True)]}"/>
                <field name="must_have_dates" invisible="1"/>
            </xpath>
        </field>
    </record>

    <record id="view_invoice_line_form" model="ir.ui.view">
        <field name="name">prepaid.cutoff.invoice_line_form</field>
        <field name="model">account.invoice.line</field>
        <field name="inherit_id" ref="account.view_invoice_line_form"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='discount']/.." position="after">
                <group name="start_end_dates">
                    <field name="start_date"
                        attrs="{'required': [('must_have_dates', '=', True)]}"/>
                    <field name="end_date"
                        attrs="{'required': [('must_have_dates', '=', True)]}"/>
                    <field name="must_have_dates" invisible="1"/>
                </group>
            </xpath>
        </field>
    </record>

    <record id="view_invoice_line_tree" model="ir.ui.view">
        <field name="name">prepaid.cutoff.invoice_line_tree</field>
        <field name="model">account.invoice.line</field>
        <field name="inherit_id" ref="account.view_invoice_line_tree"/>
        <field name="arch" type="xml">
            <field name="account_id" position="after">
                <field name="start_date"
                    attrs="{'required': [('must_have_dates', '=', True)]}"/>
                <field name="end_date"
                    attrs="{'required': [('must_have_dates', '=', True)]}"/>
                <field name="must_have_dates" invisible="1"/>
            </field>
        </field>
    </record>

</flectra>