在odoo的父模型树视图中显示来自子模型的字段值

如何解决在odoo的父模型树视图中显示来自子模型的字段值

我想使用父模型中的 one2many 字段和计算字段在父模型树视图中显示来自子模型的值。我的代码

class PurchaseRequest(models.Model):
    _name = 'purchase.request'
    _description = 'Purchase Request'

    estimated_costs = fields.Monetary(
       string='Estimated Cost',compute='_compute_estimated_cost',help='Estimated cost of Purchase Request Line,not propagated to PO.',store=True,readonly=True)
    line_ids = fields.One2many('purchase.request.line','request_id','Products to Purchase',readonly=False,copy=True,track_visibility='onchange')

    @api.multi
    @api.depends('line_ids.estimated_cost')
    def _compute_estimated_cost(self):
        for move in self:
            estimated_costs = 0.0
            for line in move.line_ids:
                estimated_costs = line.estimated_cost

class PurchaseRequestLine(models.Model):
    _name = "purchase.request.line"
    _description = "Purchase Request Line"

    estimated_cost = fields.Monetary(
        string='Estimated Cost',currency_field='currency_id',default=0.0,not propagated to PO.')