django - 向 Django Admin 添加字段总和的行

Question

我有一个发票应用程序，我希望能够在底部的管理面板中显示发票总额。（我正在使用 Django 套装）

在 Django 中是否有一种简单的方法可以做到这一点？

e：这样的事情应该工作吗？

class InvoiceAdmin(admin.ModelAdmin):
    inlines = [InvoiceItemInline]
    list_display = ('description', 'date', 'status', 'invoice_amount')

    def invoice_amount(self, request):
        amount = InvoiceItem.objects.filter(invoice__id=request.id).values_list('price', flat=True)
        quantity = InvoiceItem.objects.filter(invoice__id=request.id).values_list('quantity', flat=True)
        total_current = amount(float) * quantity(float)
        total_amount = sum(total_current)
        return total_amount

Answer 1

您在正确的轨道上，除了list_display仅适用于列出所有发票的页面，在编辑特定发票时您不会看到

要在编辑特定发票时查看它，我认为您需要覆盖该change_view方法，该方法称为视图函数：
https://docs.djangoproject.com/en/1.7/ref/contrib/admin/#django.contrib。 admin.ModelAdmin.change_view

像这样的东西：

class InvoiceAdmin(admin.ModelAdmin):
    inlines = [InvoiceItemInline]
    list_display = ('description', 'date', 'status', 'invoice_amount')

    # You need to customise the template to make use of the new context var
    change_form_template = 'admin/myapp/extras/mymodelname_change_form.html'

    def _invoice_amount(self, invoice_id):
        # define our own method to serve both cases
        order_values = InvoiceItem.objects.filter(invoice__id=invoice_id).values_list(
            'price', 'quantity', flat=True)
        return reduce(
            lambda total, (price, qty): total + (price * qty),
            order_values,
            0
        )

    def invoice_amount(self, instance):
        # provides order totals for invoices list view
        return self._invoice_amount(instance.pk)

    def change_view(self, request, object_id, form_url='', extra_context=None):
        # provides order total on invoice change view
        extra_context = extra_context or {}
        extra_context['order_total'] = self._invoice_amount(object_id)
        return super(MyModelAdmin, self).change_view(request, object_id,
            form_url, extra_context=extra_context)

请注意，您也需要覆盖更改表单模板以使用order_total我们发送回的变量extra_context