向Django Admin添加一行字段总和

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-suit）

在Django中有一种简单的方法吗？

是的：这样的事情应该有用吗？

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

您走在正确的轨道上，只是list_display仅适用于列出所有发票的页面，编辑特定发票时您将看不到

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

这样的事情：

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，您还需要覆盖更改表单模板，以便使用我们在order_total

中发回的extra_context变量