python – Creating your own django admin field

Question:

Good afternoon. I have a task to store in the database a string, 24 * 7 long, consisting of zeros and ones. In the admin panel, I want to see seven columns with 24 checkboxes in each: if the checkbox is checked, then 1 is put in the corresponding place in the line in the database, if it is unchecked – 0.

To implement this I am trying to write my own field and widget

The following is a description of the model (partially) model.py:

from django.db import models
from places.widgets import *
from places.fields import *

class Place(models.Model):
    …
    time =          HoursWorkByWeekField()
    …

Further, in fact, fields.py

from django.forms import fields
from django.db import models

from places.widgets import HoursWorkByWeekWidget

class HoursWorkByWeekField(models.CharField):
    widget = HoursWorkByWeekWidget

    def __init__(self):
        super(HoursWorkByWeekField, self).__init__(max_length=24*7, min_length=24*7)

    def to_python(self, value):
        return list(value)

    def get_db_prep_value(self, value):
        result = []
        for i in range(24*7):
            if value[i] :
                result += ['1']
            else :
                result += ['0']
        return ''.join(result)

and widgets.py

from django.forms import widgets

class HoursWorkByDayWidget(widgets.CheckboxSelectMultiple):
    def render(self, name, attrs=None):
        choices = range(0,24,1)
        return widgets.CheckboxSelectMultiple.render(self, name, attrs, choices)

class HoursWorkByWeekWidget(widgets.MultiWidget):
    def __init__(self, attrs=None):
        widgets = (
            HoursWorkByDayWidget(),
            HoursWorkByDayWidget(),
            HoursWorkByDayWidget(),
            HoursWorkByDayWidget(),
            HoursWorkByDayWidget(),
            HoursWorkByDayWidget(),
            HoursWorkByDayWidget(),
        )
        super(HoursWorkByWeekWidget, self).__init__(widgets, attrs)

When you try to run syncdb after the time attribute is not created in the database.

Answer:

Try to add

__metaclass__ = models.SubfieldBase

The SubfieldBase metaclass