[Django]-Django admin: How to display the field marked as "editable=False" in the model?

Update

This solution is useful if you want to keep the field editable in Admin but non-editable everywhere else. If you want to keep the field non-editable throughout then @Till Backhaus’ answer is the better option.

Original Answer

One way to do this would be to use a custom ModelForm in admin. This form can override the required field to make it editable. Thereby you retain editable=False everywhere else but Admin. For e.g. (tested with Django 1.2.3)

# models.py
class FooModel(models.Model):
    first = models.CharField(max_length = 255, editable = False)
    second  = models.CharField(max_length = 255)

    def __unicode__(self):
        return "{0} {1}".format(self.first, self.second)

# admin.py
class CustomFooForm(forms.ModelForm):
    first = forms.CharField()

    class Meta:
        model = FooModel
        fields = ('second',)

class FooAdmin(admin.ModelAdmin):
    form = CustomFooForm

admin.site.register(FooModel, FooAdmin)

Add the fields you want to display on your admin page.

Then add the fields you want to be read-only.

Your read-only fields must be in fields as well.

class MyModelAdmin(admin.ModelAdmin):
    fields = ['title', 'author', 'published_date', 'updated_date', 'created_date']
    readonly_fields = ('updated_date', 'created_date')

You could also set the readonly fields as editable=False in the model (django doc reference for editable here). And then in the Admin overriding the get_readonly_fields method.

# models.py
class MyModel(models.Model):
  first = models.CharField(max_length=255, editable=False)

# admin.py
class MyModelAdmin(admin.ModelAdmin):
  def get_readonly_fields(self, request, obj=None):
    return [f.name for f in obj._meta.fields if not f.editable]

With the above solution I was able to display hidden fields for several objects but got an exception when trying to add a new object.

So I enhanced it like follows:

class HiddenFieldsAdmin(admin.ModelAdmin):
def get_readonly_fields(self, request, obj=None):
    try:
        return [f.name for f in obj._meta.fields if not f.editable]
    except:
        # if a new object is to be created the try clause will fail due to missing _meta.fields
        return ""

And in the corresponding admin.py file I just had to import the new class and add it whenever registering a new model class

from django.contrib import admin
from .models import Example, HiddenFieldsAdmin

admin.site.register(Example, HiddenFieldsAdmin)

Now I can use it on every class with non-editable fields and so far I saw no unwanted side effects.

You can try this

@admin.register(AgentLinks)
class AgentLinksAdmin(admin.ModelAdmin):
    readonly_fields = ('link', )

You can display editable=False fields with readonly_fields as shown below:

@admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
    readonly_fields = ('updated_date', 'created_date')

And, if assigning editable=False fields to fields, you also need to assign them to readonly_fields as shown below:

@admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
    fields = ('updated_date', 'created_date')
    readonly_fields = ('updated_date', 'created_date')

Because, if only assigning editable=False fields to fields without assigning them to readonly_fields as shown below:

@admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
    fields = ('updated_date', 'created_date')
    # readonly_fields = ('updated_date', 'created_date')

Then, the error below occurs:

django.core.exceptions.FieldError: ‘updated_date’ cannot be specified
for MyModel model form as it is a non-editable field. Check
fields/fieldsets/exclude attributes of class MyModelAdmin.