I would like to mark the opportunity stages readonly. I've tried the following ways

Method 1

'stage_id': fields.many2one('crm.case.stage', 'Stage', track_visibility='onchange',
                    domain="['&', '&', ('fold', '=', False), ('section_ids', '=', section_id), '|', ('type', '=', type), ('type', '=', 'both')]",readonly=True),

Method 2

<field name="stage_id" widget="statusbar" clickable="False"
                        domain="['&amp;', '|', ('case_default', '=', True), ('section_ids', '=', section_id), '|', ('type', '=', type), ('type', '=', 'both')]"
                        on_change="onchange_stage_id(stage_id)"/>

Both the methods didn't work out. Kindly help me to do this.