A widget is Django’s representation of a HTML input element. The widget handles the rendering of the HTML, and the extraction of data from a GET/POST dictionary that corresponds to the widget.
Whenever you specify a field on a form, Django will use a default widget that is appropriate to the type of data that is to be displayed. To find which widget is used on which field, see the documentation about Built-in Field classes.
However, if you want to use a different widget for a field, you can just use the widget argument on the field definition. For example:
from django import forms
class CommentForm(forms.Form):
name = forms.CharField()
url = forms.URLField()
comment = forms.CharField(widget=forms.Textarea)
This would specify a form with a comment that uses a larger Textarea widget, rather than the default TextInput widget.
Many widgets have optional extra arguments; they can be set when defining the widget on the field. In the following example, the years attribute is set for a SelectDateWidget:
from django.forms.fields import DateField, ChoiceField, MultipleChoiceField
from django.forms.widgets import RadioSelect, CheckboxSelectMultiple
from django.forms.extras.widgets import SelectDateWidget
BIRTH_YEAR_CHOICES = ('1980', '1981', '1982')
GENDER_CHOICES = (('m', 'Male'), ('f', 'Female'))
FAVORITE_COLORS_CHOICES = (('blue', 'Blue'),
('green', 'Green'),
('black', 'Black'))
class SimpleForm(forms.Form):
birth_year = DateField(widget=SelectDateWidget(years=BIRTH_YEAR_CHOICES))
gender = ChoiceField(widget=RadioSelect, choices=GENDER_CHOICES)
favorite_colors = forms.MultipleChoiceField(required=False,
widget=CheckboxSelectMultiple, choices=FAVORITE_COLORS_CHOICES)
See the Built-in widgets for more information about which widgets are available and which arguments they accept.
Widgets inheriting from the Select widget deal with choices. They present the user with a list of options to choose from. The different widgets present this choice differently; the Select widget itself uses a <select> HTML list representation, while RadioSelect uses radio buttons.
Select widgets are used by default on ChoiceField fields. The choices displayed on the widget are inherited from the ChoiceField and changing ChoiceField.choices will update Select.choices. For example:
>>> from django import forms
>>> CHOICES = (('1', 'First',), ('2', 'Second',)))
>>> choice_field = forms.ChoiceField(widget=forms.RadioSelect, choices=CHOICES)
>>> choice_field.choices
[('1', 'First'), ('2', 'Second')]
>>> choice_field.widget.choices
[('1', 'First'), ('2', 'Second')]
>>> choice_field.widget.choices = ()
>>> choice_field.choices = (('1', 'First and only',),)
>>> choice_field.widget.choices
[('1', 'First and only')]
Widgets which offer a choices attribute can however be used with fields which are not based on choice – such as a CharField – but it is recommended to use a ChoiceField-based field when the choices are inherent to the model and not just the representational widget.
When Django renders a widget as HTML, it only renders the bare minimum HTML - Django doesn’t add a class definition, or any other widget-specific attributes. This means that all TextInput widgets will appear the same on your Web page.
If you want to make one widget look different to another, you need to specify additional attributes for each widget. When you specify a widget, you can provide a list of attributes that will be added to the rendered HTML for the widget.
For example, take the following simple form:
from django import forms
class CommentForm(forms.Form):
name = forms.CharField()
url = forms.URLField()
comment = forms.CharField()
This form will include three default TextInput widgets, with default rendering – no CSS class, no extra attributes. This means that the input boxes provided for each widget will be rendered exactly the same:
>>> f = CommentForm(auto_id=False)
>>> f.as_table()
<tr><th>Name:</th><td><input type="text" name="name" /></td></tr>
<tr><th>Url:</th><td><input type="text" name="url"/></td></tr>
<tr><th>Comment:</th><td><input type="text" name="comment" /></td></tr>
On a real Web page, you probably don’t want every widget to look the same. You might want a larger input element for the comment, and you might want the ‘name’ widget to have some special CSS class. To do this, you use the Widget.attrs argument when creating the widget:
For example:
class CommentForm(forms.Form):
name = forms.CharField(
widget=forms.TextInput(attrs={'class':'special'}))
url = forms.URLField()
comment = forms.CharField(
widget=forms.TextInput(attrs={'size':'40'}))
Django will then include the extra attributes in the rendered output:
>>> f = CommentForm(auto_id=False)
>>> f.as_table()
<tr><th>Name:</th><td><input type="text" name="name" class="special"/></td></tr>
<tr><th>Url:</th><td><input type="text" name="url"/></td></tr>
<tr><th>Comment:</th><td><input type="text" name="comment" size="40"/></td></tr>
Django provides a representation of all the basic HTML widgets, plus some commonly used groups of widgets:
This abstract class cannot be rendered, but provides the basic attribute attrs.
A dictionary containing HTML attributes to be set on the rendered widget.
>>> name = forms.TextInput(attrs={'size': 10, 'title': 'Your name',})
>>> name.render('name', 'A name')
u'<input title="Your name" type="text" name="name" value="A name" size="10" />'
File upload input: <input type='file' ...>, with an additional checkbox input to clear the field’s value, if the field is not required and has initial data.
Date input as a simple text box: <input type='text' ...>
Takes one optional argument:
The format in which this field’s initial value will be displayed.
If no format argument is provided, the default format is the first format found in DATE_INPUT_FORMATS and respects Format localization.
Date/time input as a simple text box: <input type='text' ...>
Takes one optional argument:
The format in which this field’s initial value will be displayed.
If no format argument is provided, the default format is the first format found in DATETIME_INPUT_FORMATS and respects Format localization.
Time input as a simple text box: <input type='text' ...>
Takes one optional argument:
The format in which this field’s initial value will be displayed.
If no format argument is provided, the default format is the first format found in TIME_INPUT_FORMATS and respects Format localization.
Similar to Select, but rendered as a list of radio buttons within <li> tags:
<ul>
<li><input type='radio' ...></li>
...
</ul>
For more granular control over the generated markup, you can loop over the radio buttons in the template. Assuming a form myform with a field beatles that uses a RadioSelect as its widget:
{% for radio in myform.beatles %}
<div class="myradio">
{{ radio }}
</div>
{% endfor %}
This would generate the following HTML:
<div class="myradio">
<label><input type="radio" name="beatles" value="john" /> John</label>
</div>
<div class="myradio">
<label><input type="radio" name="beatles" value="paul" /> Paul</label>
</div>
<div class="myradio">
<label><input type="radio" name="beatles" value="george" /> George</label>
</div>
<div class="myradio">
<label><input type="radio" name="beatles" value="ringo" /> Ringo</label>
</div>
That included the <label> tags. To get more granular, you can use each radio button’s tag and choice_label attributes. For example, this template...
{% for radio in myform.beatles %}
<label>
{{ radio.choice_label }}
<span class="radio">{{ radio.tag }}</span>
</label>
{% endfor %}
...will result in the following HTML:
<label>
John
<span class="radio"><input type="radio" name="beatles" value="john" /></span>
</label>
<label>
Paul
<span class="radio"><input type="radio" name="beatles" value="paul" /></span>
</label>
<label>
George
<span class="radio"><input type="radio" name="beatles" value="george" /></span>
</label>
<label>
Ringo
<span class="radio"><input type="radio" name="beatles" value="ringo" /></span>
</label>
If you decide not to loop over the radio buttons – e.g., if your template simply includes {{ myform.beatles }} – they’ll be output in a <ul> with <li> tags, as above.
Similar to SelectMultiple, but rendered as a list of check buttons:
<ul>
<li><input type='checkbox' ...></li>
...
</ul>
Wrapper around multiple other widgets. You’ll probably want to use this class with MultiValueField.
Its render() method is different than other widgets’, because it has to figure out how to split a single value for display in multiple widgets.
Subclasses may implement format_output, which takes the list of rendered widgets and returns a string of HTML that formats them any way you’d like.
The value argument used when rendering can be one of two things:
In the second case – i.e., if the value is not a list – render() will first decompress the value into a list before rendering it. It does so by calling the decompress() method, which MultiWidget‘s subclasses must implement. This method takes a single “compressed” value and returns a list. An example of this is how SplitDateTimeWidget turns a datetime value into a list with date and time split into two seperate values:
class SplitDateTimeWidget(MultiWidget):
# ...
def decompress(self, value):
if value:
return [value.date(), value.time().replace(microsecond=0)]
return [None, None]
When render() executes its HTML rendering, each value in the list is rendered with the corresponding widget – the first value is rendered in the first widget, the second value is rendered in the second widget, etc.
MultiWidget has one required argument:
An iterable containing the widgets needed.
Wrapper (using MultiWidget) around two widgets: DateInput for the date, and TimeInput for the time.
SplitDateTimeWidget has two optional attributes:
Similar to DateInput.format
Similar to TimeInput.format
Wrapper around three Select widgets: one each for month, day, and year. Note that this widget lives in a separate file from the standard widgets.
Takes one optional argument:
An optional list/tuple of years to use in the “year” select box. The default is a list containing the current year and the next 9 years.
Dec 14, 2013