Looking for django Answers? Try Ask4KnowledgeBase
Looking for django Keywords? Try Ask4Keywords

Django Composite widget


Example

You can create widgets composed of multiple widgets using MultiWidget.

from datetime import date

from django.forms.widgets import MultiWidget, Select
from django.utils.dates import MONTHS

class SelectMonthDateWidget(MultiWidget):
    """This widget allows the user to fill in a month and a year.

    This represents the first day of this month or, if `last_day=True`, the
    last day of this month.
    """

    default_nb_years = 10

    def __init__(self, attrs=None, years=None, months=None, last_day=False):
        self.last_day = last_day

        if not years:
            this_year = date.today().year
            years = range(this_year, this_year + self.default_nb_years)
        if not months:
            months = MONTHS

        # Here we will use two `Select` widgets, one for months and one for years
        widgets = (Select(attrs=attrs, choices=months.items()),
                   Select(attrs=attrs, choices=((y, y) for y in years)))
        super().__init__(widgets, attrs)

    def format_output(self, rendered_widgets):
        """Concatenates rendered sub-widgets as HTML"""
        return (
            '<div class="row">'
            '<div class="col-xs-6">{}</div>'
            '<div class="col-xs-6">{}</div>'
            '</div>'
        ).format(*rendered_widgets)

    def decompress(self, value):
        """Split the widget value into subwidgets values.
        We expect value to be a valid date formated as `%Y-%m-%d`.
        We extract month and year parts from this string.
        """
        if value:
            value = date(*map(int, value.split('-')))
            return [value.month, value.year]
        return [None, None]

    def value_from_datadict(self, data, files, name):
        """Get the value according to provided `data` (often from `request.POST`)
        and `files` (often from `request.FILES`, not used here)
        `name` is the name of the form field.

        As this is a composite widget, we will grab multiple keys from `data`.
        Namely: `field_name_0` (the month) and `field_name_1` (the year).
        """
        datalist = [
            widget.value_from_datadict(data, files, '{}_{}'.format(name, i))
            for i, widget in enumerate(self.widgets)]
        try:
            # Try to convert it as the first day of a month.
            d = date(day=1, month=int(datelist[0]), year=int(datelist[1]))
            if self.last_day:
                # Transform it to the last day of the month if needed
                if d.month == 12:
                    d = d.replace(day=31)
                else:
                    d = d.replace(month=d.month+1) - timedelta(days=1)
        except (ValueError, TypeError):
            # If we failed to recognize a valid date
            return ''
        else:
            # Convert it back to a string with format `%Y-%m-%d`
            return str(d)