from openerp import models, fields, api


class TodooTask(models.Model):
    """task model"""
    _name = 'todoo.task'
    name = fields.Char('Description', required=True)
    is_done = fields.Boolean('Is done ?')
    active = fields.Boolean('Is active', default=True)

    @api.one
    def do_toggle_done(self):
        self.is_done = not self.is_done
        return True

    @api.multi
    def do_clear_done(self):
        done_recs = self.search([('is_done', '=', True)])
        done_recs.write({'active': False})
        return True






<?xml version="1.0"?>
<openerp>
    <data>
        <record id="view_form_todoo_task" model="ir.ui.view">
            <field name="name">To-do Task Form</field>
            <field name="model">todoo.task</field>
            <field name="arch" type="xml">
                <form>
                    <header>
                         <button name="do_toggle_done" type="object" string="Toggle Done" class="oe_highlight" />
                         <button name="do_clear_done" type="object" string="Clear All Done" />
                    </header>
                    <sheet>
                        <group name="group_top">
                            <group name="group-left">
                                <field name="name"/>
                            </group>
                            <group name="group-right">
                                <field name="is_done"/>
                                <field name="active" readonly="1"/>
                            </group>
                        </group>
                     </sheet>
                </form>
            </field>
        </record>

        <!-- Action to open To-do Task list -->
        <act_window id="action_todoo_task"
            name="To-do Task"
            res_model="todoo.task"
            view_mode="tree,form" />
        <!-- Menu item to open To-do Task list -->
        <menuitem id="menu _todoo_task"
            name="To-Do Tasks"
            parent="mail.mail_feeds"
            sequence="20"
            action="action_todoo_task" />
    </data>

</openerp>