formfield_overrides doesn't work

[Tim Johnson]

django 2.1.5 with python 3.7.2

I have a models.py class as follows:
class Article(models.Model):
title = models.CharField(max_length=255,)

And I want to override the rendered default size attribute to 100 in
the input/text form field.

the template rendering is done as follows
<form method="post">
{% csrf_token %}
{{ form.as_p}}
<button class="btn btn-dark ml-2" type="submit">Save</button>
</form>

in the application admin.py I have the following:
class ArticleAdmin(admin.ModelAdmin):
formfield_overrides = {
models.CharField: {'widget': TextInput(attrs={'size': '100'}), },
}
# registered as
admin.site.register(Article, ArticleAdmin)

Sadly it appears to have no effect.
Viewing the rendered source, I do not see a size attribute.
the field is rendered as:
<input type="text" name="title" maxlength="255" required id="id_title">

Have I ommited a step?
thanks
--
Tim Johnson
http://www.tj49.com

[Tim Johnson]

* Tim Johnson <t...@akwebsoft.com> [190511 11:20]:

Still no luck.
Tried a custom class:

class LongTextinput(TextInput):
def __init__(self, *args, **kwargs):
attrs = kwargs.setdefault('attrs', {})
attrs.setdefault('size', 100)
super(LongTextinput, self).__init__(*args, **kwargs)
...
formfield_overrides = {
models.CharField: {'widget': LongTextinput},
}

No luck.
Replace admin.site.register with decorator:
@admin.register(Article)
still no luck.

ArticleAdmin has an additional item, with
full code below
@admin.register(Article)
class ArticleAdmin(admin.ModelAdmin):
inlines = [CommentInline]
formfield_overrides = {
models.CharField: {'widget': LongTextinput},
}

It appears that inlines is being executed.
It says right here:
https://stackoverflow.com/questions/910169/resize-fields-in-django-admin

that it is supposed to be easy, but after hours of tweaking, I'm convinced that
formfield_overrides is being ignored.

[Joe Reitman]

Tim,

Here is an example of a custom form field limiting the input to 100 characters. The model is defined to accept 255 chars. BTW, the text widget 'attrs' sets the HTML form element attributes.

class SearchForm(forms.Form):

 search_for = forms.CharField(
 label='',
 label_suffix='',
 max_length=100,
 required=True,
 widget=forms.TextInput(attrs={'placeholder': 'search', ' autofocus': ''}),
 help_text='',
 error_messages={'required': ''},
 )

[Tim Johnson]

* Joe Reitman <jreit...@gmail.com> [190512 10:31]:

> Tim,
>
> Here is an example of a custom form field limiting the input to 100
> characters. The model is defined to accept 255 chars. BTW, the text widget
> 'attrs' sets the HTML form element attributes.
>
> class SearchForm(forms.Form):
>
> search_for = forms.CharField(
> label='',
> label_suffix='',
> max_length=100,
> required=True,
> widget=forms.TextInput(attrs={'placeholder': 'search', ' autofocus': ''}),
> help_text='',
> error_messages={'required': ''},
> )

Hi Joe:
Thanks for the reply.
I did try using a custom class in admin.py

class LongTextinput(TextInput):
def __init__(self, *args, **kwargs):
attrs = kwargs.setdefault('attrs', {})

# code below aims to add a size="100" attribute
# to rendered html

attrs.setdefault('size', 100)
super(LongTextinput, self).__init__(*args, **kwargs)

implemented with formfields_ovverides as
in :

formfield_overrides = {
models.CharField: {'widget': LongTextinput},
}

but did not have the desired effect.

the larger question is:
why is formfield_overrides not having the effect I expected?
I.E. size="100" is added to the rendered html.

According to documentation the implementation should be pretty straightforward.

Do you suppose that there is a particular plugin that enables formfield_overrides?

**OR** is {{ form.as_p }} in the template inhibiting the rendering?

My goal was not to change the max_length attribute, but the size attribute in
the rendered HTML code.

For the record, css widens the input field, and that gave me the
input width I sought, but the edification I seek is to understand
how to use formfield_overrides.

cheers

[Joe Reitman]

Tim,

I found this in the Django source code on Github searching for 'formfield_overrides'. It is in a test module testing formfield_overrides functionality. I'm assuming you imported TextInput from forms? This should work to change your admin display. Are trying to change your Admin panel form or a form going out to the user?

class BandAdmin(admin.ModelAdmin):  formfield_overrides = {  CharField: {'widget': forms.TextInput(attrs={'size': '10'})}  }

Regards,

Joe

On Saturday, May 11, 2019 at 2:10:06 PM UTC-5, tim042849 wrote:

[Tim Johnson]

* Joe Reitman <jreit...@gmail.com> [190512 13:34]:

> Tim,
>
> I found this in the Django source code on Github searching for
> 'formfield_overrides'. It is in a test module testing formfield_overrides
> functionality. I'm assuming you imported TextInput from forms? This should

> work to change your *admin* display. Are trying to change your Admin panel

> form or a form going out to the user?
>
>
> class BandAdmin(admin.ModelAdmin):
> formfield_overrides = {
> CharField: {'widget': forms.TextInput(attrs={'size': '10'})}
> }

I am trying to change a form going to the user.
The form in the admin page __does__ show the size attribute in
the HTML source code for input/text.

So it appears that formfield_overrides only affects the admin
page.

I'm going to call this solved - given that I can "widen" the field
with css.

Thanks again Joe. You've been a great help and I've learned a lot.
cheers

[Jim Illback]

Tim, this won’t help you to use or solve the formfield_overrides issues, but maybe it will be helpful. I’ve not tried this for a CharField, but it works great on a TextField (which has no max_length, so model size isn’t impacted):

1. Install  widget tweaks and add {% load widget_tweaks %} at the top of your HTML page.

2. On your HTML page, instantiate the field using this format: {{ form.notes|attr:"rows:20"|attr:"cols:50" }} - you can use either row/cols or both as in this case, and any char size.

Here’s a great usage example on widget tweaks: https://simpleisbetterthancomplex.com/2015/12/04/package-of-the-week-django-widget-tweaks.html.

I hope this is useful for you.

Jim Illback

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[Tim Johnson]

* Jim Illback <suba...@hotmail.com> [190512 14:22]:

> Tim, this won’t help you to use or solve the formfield_overrides issues, but maybe it will be helpful. I’ve not tried this for a CharField, but it works great on a TextField (which has no max_length, so model size isn’t impacted):
>
> 1. Install widget tweaks and add {% load widget_tweaks %} at the top of your HTML page.
> 2. On your HTML page, instantiate the field using this format: {{ form.notes|attr:"rows:20"|attr:"cols:50" }} - you can use either row/cols or both as in this case, and any char size.
>
> Here’s a great usage example on widget tweaks: https://simpleisbetterthancomplex.com/2015/12/04/package-of-the-week-django-widget-tweaks.html.
>
> I hope this is useful for you.

Thanks Jim. I had seen references to 'tweaks'
and I will give it a try.