How to customise the admin for a measurement type#

The registry generates an administration page for each measurement type. You replace it with your own class when the list needs other columns, filters or search fields, or the form needs a different layout.

Before you start#

You need a registered measurement type. This guide uses GrainSizeMeasurement from How to add a measurement type.

Steps#

Subclass MeasurementChildAdmin in the app’s admin.py. Start each list from the base class’s list, so the columns, filters and search fields every measurement has stay in place.
```
# sediments/admin.py
from fairdm.core.measurement.admin import MeasurementChildAdmin


class GrainSizeMeasurementAdmin(MeasurementChildAdmin):
    list_display = [*MeasurementChildAdmin.list_display, "method"]
    list_filter = [*MeasurementChildAdmin.list_filter, "method"]
    search_fields = [*MeasurementChildAdmin.search_fields, "method"]
```
The base class lists name, sample, dataset, the measurement type, added and modified. Its dataset filter offers private datasets too, so keep the base list_filter rather than writing "dataset" yourself. The base class also adds inlines for descriptions, dates, identifiers and credits.

To lay out the form yourself, set fieldsets. A field you leave out is not shown.

class GrainSizeMeasurementAdmin(MeasurementChildAdmin):
    ...
    fieldsets = [
        (None, {"fields": ["name", "sample", "dataset", "image"]}),
        ("Grain size", {"fields": ["method", "value", "uncertainty"]}),
        (
            "Location",
            {
                "fields": [
                    "location",
                    "location_elevation",
                    "location_uncertainty",
                ],
                "classes": ["collapse"],
            },
        ),
        (
            "Metadata",
            {"fields": ["uuid", "added", "modified"], "classes": ["collapse"]},
        ),
    ]

Without fieldsets, the form shows the base fields first, then your type’s own fields under “Contents”, then the metadata.

Name the class in the type’s configuration with admin_class.
```
# sediments/config.py
from .admin import GrainSizeMeasurementAdmin


@register
class GrainSizeMeasurementConfig(BaseMeasurementConfiguration):
    model = GrainSizeMeasurement
    fields = ["name", "sample", "dataset", "method", "value", "uncertainty"]
    admin_class = GrainSizeMeasurementAdmin
```
admin_class also takes the class’s dotted path as a string. The class must subclass MeasurementChildAdmin, or the portal refuses to start with a ConfigurationError. Do not set admin_list_display alongside it, because a field list and a class for the same component are refused together.

The result#

The administration page of the type uses your class, and the registry generates none for it. The other generated components, the form, table, filter set and serializer, are unchanged.

You can register the admin class yourself instead with @admin.register(GrainSizeMeasurement) in admin.py. The registry leaves a model that is already registered with the admin alone. Naming the class in admin_class keeps every choice about the type in its configuration, which is why this guide uses it.

The base class’s attributes follow Measurement model. The options of the configuration are on Model configuration.