重新定义admin.py中的Hero管理模型如下：
python">@admin.register(Hero)
class HeroAdmin(admin.ModelAdmin):list_display = ("name", "is_immortal", "category", "origin", "is_very_benevolent")list_filter = ("is_immortal", "category", "origin",)def is_very_benevolent(self, obj):return obj.benevolence_factor > 75它具有一个计算字段is_very_benevolent，Admin后台显示如下：
我们已经在来自模型属性字段上添加了过滤，但是还想在计算出的字段上添加过滤。为此，我们可以通过继承SimpleListFilter类实现：
python">class IsVeryBenevolentFilter(admin.SimpleListFilter):title = 'is_very_benevolent'parameter_name = 'is_very_benevolent'def lookups(self, request, model_admin):return (('Yes', 'Yes'),('No', 'No'),)def queryset(self, request, queryset):value = self.value()if value == 'Yes':return queryset.filter(benevolence_factor__gt=75)elif value == 'No':return queryset.exclude(benevolence_factor__gt=75)return queryset
然后将更改list_filter为list_filter = ("is_immortal", "category", "origin", IsVeryBenevolentFilter)
这样，便可以对计算出的字段进行过滤。修改后管理后台显示如下：
如何对计算字段修改成系统自带的布尔类型显示效果，增加is_very_benevolent.boolean = True代码，HeroAdmin管理模型修改如下：
python">@admin.register(Hero)
class HeroAdmin(admin.ModelAdmin):list_display = ("name", "is_immortal", "category", "origin", "is_very_benevolent")list_filter = ("is_immortal", "category", "origin", IsVeryBenevolentFilter)def is_very_benevolent(self, obj):return obj.benevolence_factor > 75is_very_benevolent.boolean = True显示效果如下：
