在Django Admin中為字段的總和添加一行

Question

我有一個發票應用程序，我希望能夠在底部的管理面板中顯示發票的總額。 （我正在使用Django-suit）

在Django中有一種簡單的方法嗎？

e：這樣的東西行嗎？

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

您處在正確的軌道上，只是list_display僅適用於列出所有發票的頁面，在編輯特定發票時看不到

為了在編輯特定發票時看到它，我認為您需要重寫change_view方法，該方法稱為視圖函數：
https://docs.djangoproject.com/zh-CN/1.7/ref/contrib/admin/#django.contrib.admin.ModelAdmin.change_view

像這樣：

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)

請注意，您還需要覆蓋變更表單模板，以利用我們以extra_context發送回的order_total變量