implement custom filter

gazetteer/places/admin.py

@@ -2,6 +2,49 @@ from django.contrib.gis import admin
 from models import *
 from django import forms
 
+
+class FeatureTypeFilter(admin.SimpleListFilter):
+    # Human-readable title which will be displayed in the
+    # right admin sidebar just above the filter options.
+    title = _('Feature Type')
+
+    # Parameter for the filter that will be used in the URL query.
+    parameter_name = 'feature_type'
+
+    def lookups(self, request, model_admin):
+        """
+        Returns a list of tuples. The first element in each
+        tuple is the coded value for the option that will
+        appear in the URL query. The second element is the
+        human-readable name for the option that will appear
+        in the right sidebar.
+        """
+        fts = tuple()
+        for ft in FeatureType.objects.all():
+            if ft.feature_set.count() > 0:
+                t = (ft.id, ft.__unicode__(),)
+                fts.append(t)
+        
+        return (
+            fts,
+        )
+
+    def queryset(self, request, queryset):
+        """
+        Returns the filtered queryset based on the value
+        provided in the query string and retrievable via
+        `self.value()`.
+        """
+        # Compare the requested value (either '80s' or 'other')
+        # to decide how to filter the queryset.
+        val = self.value()
+        return queryset.filter(feature_type=val)        
+
+
+class PersonAdmin(ModelAdmin):
+    list_filter = (DecadeBornListFilter,)
+
+
 class FeatureNamesInline(admin.StackedInline):
     model = Name
     extra = 0
@@ -28,6 +71,7 @@ class FeatureAdmin(admin.OSMGeoAdmin):
     inlines = [FeatureNamesInline]
     list_display = ('__unicode__', 'feature_type_name', 'time_start', 'time_end',)
     list_per_page = 12
+    list_filter = ('feature_type__feature_class',)
     openlayers_url = 'http://openlayers.org/dev/OpenLayers.js'
     openlayers_img_path = None
     form = featuresForm