How to get field value from another Many2many field? - python-2.7

Question

I use odoo 10 and I created a custom module to plan trips. I create a view for the plans in which I will select the list of my travels. My problem now is how I can get the Start and Destination fields of each trip insert in this view knowing that the field that displays the list of trips is travel_ids = fields.Many2many ('tms.travel', copy = False, string = 'Travels'). I try a lot but no result. Any idea for help please ??
tms_travel_planning.xml
<?xml version="1.0" encoding="UTF-8"?>
<odoo>
<data>
<record id="view_tms_travel_planning_form" model="ir.ui.view">
<field name="name">view.tms.travel.planning.form</field>
<field name="model">tms.planning</field>
<field name="arch" type="xml">
<form string="Plannification des voyage">
<header>
<field name="state" statusbar_visible="draft,approved,confirmed" widget="statusbar"/>
</header>
<sheet>
<div class="oe_title">
<h1>
<label class="oe_inline" style="font-size:30px;" string="Plannification - " attrs="{'invisible':[('name','=', False)]}"/>
<field name="name" readonly="1"/>
</h1>
</div>
<group>
<group>
<field name="datetime"/>
<field attrs="{'readonly':[('state','in',('confirmed', 'cancel'))]}" name="operating_unit_id"/>
</group>
<group>
<field name="num_vehicule_dispo"/>
<field name="num_chauffeur_dispo"/>
</group>
</group>
<notebook colspan="1">
<page string="Les voyages à planifier">
<separator coslpan="4" string="Voyages"/>
<!--<field attrs="{'readonly':[('state','in',('confirmed', 'cancel'))]}" name="operating_unit_id"/>-->
<field attrs="{'readonly':[('state','in',('confirmed', 'cancel'))]}" colspan="4"
domain="[('state','not in',('cancel','closed'))]" name="travel_ids" nolabel="1"/>
<separator coslpan="4" string="Véhicules"/>
<field colspan="4" name="fleet_ids" nolabel="1"/>
<separator coslpan="4" string="Conducteurs"/>
<field colspan="4" name="employee_ids" nolabel="1"/>
</page>
</notebook>
</sheet>
</form>
</field>
</record>
</data>
</odoo>
tms_travel_planning.py
# -*- coding: utf-8 -*-
from odoo import _, api, fields, models
from odoo.exceptions import ValidationError
class TmsTravelPlanning(models.Model):
_name = 'tms.planning'
name = fields.Char('Num du plannification')
operating_unit_id = fields.Many2one(
'operating.unit', string='Operating Unit', required=True)
id_planning=fields.Integer(string="Numéro du plannification")
datetime=fields.Date(string="Date")
num_vehicule_dispo=fields.Integer(string="Nombre de véhicule disponible")
num_chauffeur_dispo=fields.Integer(string="Nombre de chauffeur disponible")
tms
fleet_ids = fields.Many2many('fleet.vehicle', copy=False, string='Véhicules')
employee_ids = fields.Many2many('hr.employee', copy=False, string='Conducteurs')
state = fields.Selection([
('draft', 'Pending'),
('approved', 'Approved'),
('confirmed', 'Confirmed'),
('cancel', 'Cancelled')], readonly=True,
help="Gives the state of the Waybill.",
default='draft')
#api.model
def create(self, values):
planning = super(TmsTravelPlanning, self).create(values)
if not planning.operating_unit_id.planning_sequence_id:
raise ValidationError(_(
'You need to define the sequence for planning in base %s' %
planning.operating_unit_id.name
))
sequence = planning.operating_unit_id.planning_sequence_id
planning.name = sequence.next_by_id()
print(str(values['num_vehicule_dispo']))
print(str(values['num_chauffeur_dispo']))
return planning
tms_travel.xml
<?xml version="1.0" encoding="UTF-8"?>
<odoo>
<record id="view_tms_travel_tree" model="ir.ui.view">
<field name="name">tms.travel.tree</field>
<field name="model">tms.travel</field>
<field name="priority">1</field>
<field name="arch" type="xml">
<tree>
<field name="name"/>
<field name="date"/>
<field name="departure_id"/>
<field name="arrival_id"/>
<field name="state"/>
<button groups="tms.group_traffic,tms.group_expenses" icon="fa-thumbs-up" name="action_progress" states="draft" string="Dispatch Travel" type="object"/>
<button groups="tms.group_traffic,tms.group_expenses" icon="fa-check-square" name="action_end" states="progress" string="End Travel" type="object"/>
</tree>
</field>
</record>
</odoo>

Answer 1

Ok, you are missing some information in your many2many relationship. here is what you need.
field_name = fields.Manmy2many('related.model', 'relational_table', 'current_model_id', 'related_model_id', string='other information')
and usually I put the inverse on the related model ex:
(On the hr.holidays model)
payslip_ids = fields.Many2many('hr.payslip', 'hr_payslip_holiday_rel', 'holiday_id', 'payslip_id', ...)
(On the hr.payslip model)
holiday_ids - fields.Many2many('hr.holidays', 'hr_payslip_holiday_rel', 'payslip_id', 'holiday_id', ...)
Then at some point you need to add one of the ids to the other model for ex:
holiday.payslip_ids |= current_payslip_id