python - Django:在 models.py 中 save() 期间 PositiveIntegerField 中 ManyToMany 字段的计数

Question

我想在保存模型期间更改 ManyToMany 字段的计数。为此我修改了 save()。如果我运行 save()，计数将不会更新。如果我第二次运行保存而不更新字段，它将更新计数。

class UserProfile(models.Model):

    follower = models.ManyToManyField('self', related_name='Followers',
        blank=True, symmetrical=False)
    following = models.ManyToManyField('self', related_name='Followings',
        blank=True, symmetrical=False)
    follower_count = models.PositiveIntegerField(null=True, blank=True,
        editable=False)
    following_count = models.PositiveIntegerField(null=True, blank=True,
        editable=False)

    class Meta:
        verbose_name = 'User Profile'
        verbose_name_plural = 'User Profiles'

    def __str__(self):
        return self.follower_count

    def save(self, *args, **kwargs):
        super(UserProfile, self).save(*args, **kwargs)
        self.following_count = self.following.all().count()

        self.follower_count = self.follower.all().count()
        super(UserProfile, self).save(*args, **kwargs)

我想用 save() 更新计数。

Answer 1

 def save(self, *args, **kwargs):
        self.following_count = self.following.all().count()
        super(UserProfile, self).save(*args, **kwargs)

先获取计数，然后调用保存方法