Django TimeField with Microseconds in Admin

You're facing a common issue with Django's TimeField in the Admin interface. While you've correctly identified that the supports_microseconds attribute needs to be set to True, there are a few issues with your implementation.

The main problem is that you need to customize both the widget and the form field to properly handle microseconds. Your current approach only addresses the widget part.

Here's a more complete solution:

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from django.forms.widgets import TimeInput
from django.forms import TimeField as FormTimeField
from django.db.models import TimeField as ModelTimeField
from django.contrib import admin

class MicrosecondTimeInput(TimeInput):
    input_type = "text"
    supports_microseconds = True  # Set this as a class attribute
    
    def __init__(self, attrs=None, format=None):
        if format is None:
            format = '%H:%M:%S.%f'
        super().__init__(attrs, format)

class MicrosecondTimeField(FormTimeField):
    widget = MicrosecondTimeInput
    
    def __init__(self, **kwargs):
        kwargs.setdefault('widget', MicrosecondTimeInput())
        super().__init__(**kwargs)

class MyModelAdmin(admin.ModelAdmin):
    formfield_overrides = {
        ModelTimeField: {'form_class': MicrosecondTimeField},
    }

Key improvements:

1. Set supports_microseconds as a class attribute rather than an instance attribute
2. Created a custom form field (MicrosecondTimeField) that uses the custom widget
3. Override the form class in formfield_overrides instead of just the widget
4. Set a default format that includes microseconds

This approach ensures that both the display and the processing of the time value maintain microsecond precision throughout the admin interface.

Make sure to import the TimeField correctly from both forms and models modules to avoid confusion.