Added “on” or “off” icons chapter

docs/boolean_fields.rst

@@ -1,2 +1,28 @@
 How to show “on” or “off” icons for calculated boolean fields?
 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+In the previous chapter, :doc:`filtering_calculated_fields` you added a boolean field.::
+
+    def is_very_benevolent(self, obj):
+        return obj.benevolence_factor > 75
+
+Which looks like this
+
+.. image:: filter_calculated_fixed.png
+
+The :code:`is_very_benevolent` field show the string `True` and `False`, unlike the builin BooleanFields which show an on and off indicator.
+To fix this, you add a :code:`boolean` attribute on your method. You final modeladmin looks like this::
+
+    @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 > 75
+
+        is_very_benevolent.boolean = True
+
+And your admin looks like this
+
+.. image:: boolean_field_fixed.png

docs/index.rst

@@ -36,6 +36,7 @@ Calculated fields
    optimize_queries
    sorting_calculated_fields
    filtering_calculated_fields
+   boolean_fields
 
 Permissions
 +++++++++++++++++++++
@@ -81,7 +82,6 @@ Listview Page
    increase_row_count
    disable_pagination
    date_based_filtering
-   boolean_fields
    many_to_many
 
 Changeview Page

heroes_and_monsters/entities/admin.py

@@ -33,6 +33,8 @@ class HeroAdmin(admin.ModelAdmin):
     def is_very_benevolent(self, obj):
         return obj.benevolence_factor > 75
 
+    is_very_benevolent.boolean = True
+
 
 @admin.register(Category)
 class CategoryAdmin(admin.ModelAdmin):