无法覆盖 save_model django admin？

Question

我不明白我做错了什么。我希望用户只添加公告模型的标题和描述，其余部分应自动填充。这是我的模型：

class Annoucement(models.Model):
    username = models.ForeignKey(User, on_delete=None)
    title = models.CharField(max_length=500, default="")
    description = models.TextField(max_length=5000, default="")
    datetime = models.DateTimeField(default=datetime.now)

    def __str__(self):
        return self.title + " " + self.username.username

这是 admin.py 文件。

from django.contrib import admin

from .models import Profile, Activity, View, Annoucement
# Register your models here.


class AnnoucementAdmin(admin.ModelAdmin):
    fields = ['title', 'description']


    def save_model(self, request, obj, form, change):
        obj.username = request.user
        print("yes")
        super(AnnoucementAdmin, self).save_model(request, obj, form, change)

admin.site.register(Profile)
admin.site.register(Activity)
admin.site.register(View)
admin.site.register(Annoucement)

此外，一旦我从管理面板保存模型，打印（“是”）也不会出现在终端上。帮助！

Answer 1

1）admin.site.register(Annoucement, AnnoucementAdmin)

'return'2）在最后添加save_model

class AnnoucementAdmin(admin.ModelAdmin):
    fields = ['title', 'description']

    def save_model(self, request, obj, form, change):
        obj.username = request.user
        print("yes")
        return super(AnnoucementAdmin, self).save_model(request, obj, form, change)