tra_backend/ohrms_holidays_approval/views/leave_request.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <record id="hr_holidays_status_validators_users" model="ir.ui.view">
        <field name="name">hr.holidays.double.validation.users</field>
        <field name="model">hr.leave</field>
        <field name="inherit_id" ref="hr_holidays.hr_leave_view_form_manager"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='holiday_type']" position="replace">
                <field name="holiday_type" string="Mode"/>
            </xpath>
            <xpath expr="//field[@name='employee_id']" position="replace">
                <field name="employee_id" attrs="{
                        'required': [('holiday_type', '=', 'employee')],
                        'invisible': [('holiday_type', '!=', 'employee')]
                        }"/>
            </xpath>
            <xpath expr="//field[@name='mode_company_id']" position="replace">
                 <field name="mode_company_id" attrs="{
                        'required': [('holiday_type', '=', 'company')],
                        'invisible': [('holiday_type', '!=', 'company')]
                        }"/>
            </xpath>
            <xpath expr="//field[@name='category_id']" position="replace">
               <field name="category_id" attrs="{
                        'required': [('holiday_type', '=', 'category')],
                        'invisible': [('holiday_type', '!=','category')]
                        }"/>
            </xpath>
            <xpath expr="//field[@name='department_id']" position="replace">
                <field name="department_id" attrs="{
                        'required': [('holiday_type', '=', 'department')],
                        'invisible': [('holiday_type', 'not in', ('employee', 'department'))]
                        }"/>
            </xpath>
        </field>
    </record>
     <record id="hr_holidays_status_double_validation" model="ir.ui.view">
        <field name="name">hr.leave.type.double.validation</field>
        <field name="model">hr.leave.type</field>
        <field name="inherit_id" ref="hr_holidays.edit_holiday_status_form"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='responsible_id']" position="attributes">
                <attribute name="attrs">
                    {'invisible': [('validation_type', 'in', ['no_validation', 'manager','multi'])],
                     'required': [('validation_type', 'in', ['hr', 'both'])]}
                </attribute>
            </xpath>
            <xpath expr="//group[last()]" position="after">
                <field name="multi_level_validation" invisible="1"/>
                <notebook attrs="{'invisible': [('validation_type','!=','multi')]}">
                    <page string="Leave validation">
                        <field name="leave_validators" mode="tree">
                            <tree string="Users" editable="bottom">
                                <field name="holiday_validators"/>
                            </tree>
                        </field>
                    </page>
                </notebook>
            </xpath>
        </field>
    </record>

    <record id="hr_holidays_status_validators_leave_create" model="ir.ui.view">
        <field name="name">hr.holidays.double.validation.create.leave</field>
        <field name="model">hr.leave</field>
        <field name="inherit_id" ref="hr_holidays.hr_leave_view_form"/>
        <field name="arch" type="xml">
            <xpath expr="//group[last()]" position="after">
                <field name="multi_level_validation" invisible="1"/>
                <notebook attrs="{'invisible': [('multi_level_validation', '=', False)]}">
                    <page string="Validation Status">
                        <field name="leave_approvals" mode="tree">
                            <tree string="Users" editable="false" create="false" delete="false">
                                <field name="validating_users"/>
                                <field name="validation_status"/>
                                <field name="leave_comments"/>
                            </tree>
                            <form>
                                <group>
                                    <field name="validating_users"/>
                                    <field name="leave_comments"/>
                                </group>
                            </form>
                        </field>
                    </page>
                </notebook>
            </xpath>
            <xpath expr="//button[@name='action_approve']" position="replace">
                <button string="Approve" name="action_approve" states="confirm" type="object" class="oe_highlight"
                        />
            </xpath>
            <xpath expr="//button[@name='action_refuse']" position="replace">
                <button string="Refuse" name="action_refuse" states="confirm,validate,validate1" type="object"
                        />
            </xpath>
        </field>
    </record>

    <record id="hr_holidays_status_validators" model="ir.ui.view">
        <field name="name">hr.holidays.double.validation</field>
        <field name="model">hr.leave</field>
        <field name="inherit_id" ref="hr_holidays.hr_leave_view_form_manager"/>
        <field name="arch" type="xml">
            <xpath expr="//group[last()]" position="after">
                <field name="multi_level_validation" invisible="1"/>
                <notebook attrs="{'invisible': [('multi_level_validation', '=', False)]}">
                    <page string="Validation Status">
                        <field name="leave_approvals" mode="tree">
                            <tree string="Users" editable="false" create="false" delete="false">
                                <field name="validating_users"/>
                                <field name="validation_status"/>
                                <field name="leave_comments"/>
                            </tree>
                            <form>
                                <group>
                                    <field name="validating_users"/>
                                    <field name="leave_comments"/>
                                </group>
                            </form>
                        </field>
                    </page>
                </notebook>
            </xpath>
            <xpath expr="//button[@name='action_approve']" position="replace">
                <button string="Approve" name="action_approve" states="confirm" type="object" class="oe_highlight"/>
            </xpath>
             <xpath expr="//button[@name='action_refuse']" position="replace">
                <button string="Refuse" name="action_refuse" states="confirm,validate,validate1" type="object"/>
            </xpath>
        </field>
    </record>

    <record id="open_holidays_to_approve" model="ir.actions.server">
        <field name="name">Approvals</field>
        <field name="model_id" ref="model_hr_leave"/>
        <field name="binding_model_id" ref="model_hr_leave"/>
        <field name="state">code</field>
        <field name="code">
           action = model._get_approval_requests()
        </field>
    </record>

    <menuitem
            id="menu_hr_holidays_leave_approvals"
            name="Approvals"
            parent="hr_holidays.menu_hr_holidays_root"
            sequence="3"/>

     <menuitem
            id="menu_open_leave_approvals"
            name="Approval Requests"
            parent="menu_hr_holidays_leave_approvals"
            action="open_holidays_to_approve"
            sequence="1"/>

</odoo>