social/mail_activity_board/views/mail_activity_view.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
<!--
    VIEWS
-->

    <!-- FORM VIEW -->
    <record id="mail_activity_view_form_board" model="ir.ui.view">
        <field name="name">mail.activity.boards.view.form</field>
        <field name="model">mail.activity</field>
        <field name="priority">30</field>
        <field name="arch" type="xml">
            <form string="Activity Form" create="false" edit="false" delete="false">
                <sheet string="Activity">
                    <button name="open_origin" type="object" class="centre oe_link" nolabel="1">
                        <h1><field name="res_name"/></h1>
                    </button>
                    <field name="activity_category" invisible="1" />
                    <field name="res_model" invisible="1"/>
                    <field name="res_model_id" invisible="1"/>
                    <field name="res_id" invisible="1"/>
                    <group>
                        <group>
                            <field name="activity_type_id" required="1" options="{'no_create': True, 'no_open': True}"/>
                            <field name="res_model_id_name"/>
                            <field name="calendar_event_id" invisible="1"/>
                            <field name="create_date" invisible="1"/>
                        </group>
                        <group>
                            <field name="date_deadline"
                                   attrs="{'invisible': [('activity_category', '=', 'meeting')]}"/>
                            <field name="calendar_event_id_start" string="Start meeting"
                                   attrs="{'invisible': [('calendar_event_id','=', False)]}"/>
                            <field name="duration" widget="float_time"
                                   attrs="{'invisible': ['|',('duration', '=', False),
                                   ('calendar_event_id','=', False)]}"/>
                            <field name="user_id" options="{'no_open': True}"/>

                        </group>
                    </group>
                    <group attrs="{'invisible': ['|',('calendar_event_id','=', False),('calendar_event_id_partner_ids','=', False)]}">
                        <field name="calendar_event_id_partner_ids" mode="kanban"/>
                    </group>
                    <group>
                        <field name="summary" placeholder="e.g. Discuss proposal"/>
                        <field name="note" placeholder="Log a note..."/>
                    </group>
                </sheet>
            </form>
        </field>
    </record>


    <!-- TREE VIEW -->
    <record id="mail_activity_view_tree" model="ir.ui.view">
        <field name="name">mail.activity.boards.view.tree</field>
        <field name="model">mail.activity</field>
        <field name="inherit_id" ref="mail.mail_activity_view_tree"/>
        <field name="arch" type="xml">
            <xpath expr="//tree" position="attributes">
                <attribute name="default_order"/>
                <attribute name="decoration-danger">(date_deadline &lt; current_date)</attribute>
                <attribute name="decoration-warning">(date_deadline == current_date)</attribute>
                <attribute name="decoration-success">(date_deadline &gt; current_date)</attribute>
            </xpath>

        </field>
    </record>


    <!-- KANBAN VIEW -->
     <record id="mail_activity_view_kanban" model="ir.ui.view">
         <field name="name">mail.activity.boards.view.kanban</field>
         <field name="model">mail.activity</field>
         <field name="priority" eval="10"/>
         <field name="arch" type="xml">
            <kanban default_group_by="activity_type_id" class="_kanban_small_column o_opportunity_kanban" create="0" _order="date_deadline"
                    group_create="false" group_delete="false" group_edit="false">
                <field name="user_id"/>
                <field name="res_id"/>
                <field name="res_name"/>
                <field name="res_model"/>
                <field name="summary"/>
                <field name="date_deadline"/>
                <field name="state"/>
                <field name="icon"/>
                <field name="activity_type_id"/>
                <field name="activity_category"/>
                <templates>
                    <t t-name="kanban-box">
                        <div t-attf-class="oe_kanban_content oe_kanban_global_click">
                            <div class="oe_kanban_content">
                                <div>
                                    <strong class="o_kanban_record_subtitle">
                                        <span t-attf-class="fa #{record.icon.raw_value}" />
                                        <field name="summary"/>
                                    </strong>
                                </div>
                                <div>
                                    <strong class="o_kanban_record_title"><field name="res_name"/></strong>
                                </div>

                                <div class="o_kanban_record_bottom">
                                    <div class="oe_kanban_bottom_left">
                                        <t t-set="act_date" t-value="new Date(record.date_deadline.raw_value)"/>
                                        <t t-if="act_date &lt; (new Date())">
                                            <span t-attf-class="text-danger"><i class="fa fa-clock-o"/></span>
                                            <t t-if="record.activity_category.raw_value!='meeting'">
                                                <span t-attf-class="text-danger">
                                                    <field name="date_deadline" t-options='{"widget": "date"}'/>
                                                </span>
                                            </t>
                                            <t t-else="">
                                                <span t-attf-class="text-danger">
                                                    <field name="calendar_event_id_start"  t-options='{"widget": "date"}'/>
                                                </span>
                                            </t>
                                        </t>
                                        <t t-else="">
                                            <span><i class="fa fa-clock-o"/></span>
                                            <t t-if="record.activity_category.raw_value!='meeting'">
                                                <span>
                                                    <field name="date_deadline"  t-options='{"widget": "date"}'/>
                                                </span>
                                            </t>
                                            <t t-else="">
                                                <field name="calendar_event_id_start"  t-options='{"widget": "date"}'/>
                                            </t>
                                        </t>
                                    </div>
                                    <div class="oe_kanban_bottom_right">
                                        <img t-att-src="kanban_image('res.users', 'image_small', record.user_id.raw_value)"
                                             t-att-title="record.user_id.value"
                                             t-att-alt="record.user_id.value" width="24" height="24" class="oe_kanban_avatar"/>
                                    </div>
                                </div>
                            </div>
                        </div>
                    </t>
                </templates>
            </kanban>
         </field>
    </record>


    <!-- SEARCH VIEW -->
    <record id="mail_activity_view_search" model="ir.ui.view">
        <field name="name">mail.activity.boards.view.search</field>
        <field name="model">mail.activity</field>
        <field name="inherit_id" ref="mail.mail_activity_view_search"/>
        <field name="priority" eval="2"/>
        <field name="mode">primary</field>
        <field name="arch" type="xml">
            <xpath expr='//field[@name="res_model_id"]' position='before'>
                <field name="user_id"/>
                <field name="res_name" string="Origin"/>
            </xpath>

            <xpath expr='//filter[@name="activities_overdue"]' position='before'>
                <filter string="Act. next month" name="activities_month"
                        domain="[('date_deadline', '&lt;', (context_today()+datetime.timedelta(days=30)).strftime('%Y-%m-%d'))]"
                        help="Show activities scheduled for next month."/>
                <filter string="Act. next 6 months" name="activities_6_month"
                        domain="[('date_deadline', '&lt;', (context_today()+datetime.timedelta(days=180)).strftime('%Y-%m-%d'))]"
                        help="Show activities scheduled for next 6 months."/>
                <separator/>
            </xpath>

            <xpath expr='//search/group' position='inside'>
                <filter string="User" name='assigned_user' context="{'group_by':'user_id'}"/>
                <filter string="Origin" name='origin' context="{'group_by': 'res_model_id'}"/>
            </xpath>

        </field>
    </record>


<!--
    ACTION
-->
    <record model="ir.actions.act_window" id="open_boards_activities">
        <field name="name">Activities</field>
        <field name="res_model">mail.activity</field>
        <field name="view_mode">kanban,form</field>
        <field name="domain">[]</field>
        <field name="context">{}</field>
        <field name="view_ids"
                   eval="[(5, 0, 0),
                          (0, 0, {'view_mode': 'kanban', 'view_id': ref('mail_activity_view_kanban')}),
                          (0, 0, {'view_mode': 'tree', 'view_id': ref('mail_activity_view_tree')}),
                          (0, 0, {'view_mode': 'form', 'view_id': ref('mail_activity_view_form_board')}),
                          (0, 0, {'view_mode': 'calendar'}),
                          (0, 0, {'view_mode': 'pivot'}),
                          (0, 0, {'view_mode': 'graph'})]"/>
        <field name="search_view_id" ref="mail_activity_view_search"/>
    </record>


<!--
Menus
-->
    <menuitem
            id="board_menu_activities"
            name="Activities"
            parent="base.menu_board_root"
            action="open_boards_activities"
            sequence="1"/>

</odoo>