How to use radio buttons in python web.py

问题:

I am using web.py framework to create a simple web application

I want to create a radio button so I wrote the following code

from web import form
from web.contrib.auth import DBAuth
import MySQLdb as mdb



render = web.template.render('templates/')

urls = (
  '/project_details',  'Project_Details',  
)

class Project_Details:

    project_details = form.Form( 
        form.Radio('Home Page'),
        form.Radio('Content'),
        form.Radio('Contact Us'),
        form.Radio('Sitemap'),
        )

    def GET(self):
        project_details = self.project_details()
        return render.projectdetails(project_details)  

When I run the code with url localhost:8080 I am seeing following error

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/web/application.py", line 237, in process
    return p(lambda: process(processors))
  File "/usr/lib/python2.7/site-packages/web/application.py", line 565, in processor
    h()
  File "/usr/lib/python2.7/site-packages/web/application.py", line 661, in __call__
    self.check(mod)
  File "/usr/lib/python2.7/site-packages/web/application.py", line 680, in check
    reload(mod)
  File "/home/local/user/python_webcode/index.py", line 68, in <module>
    class Project_Details:
  File "/home/local/user/python_webcode/index.py", line 72, in Project_Details
    form.Radio('password'),
TypeError: __init__() takes at least 3 arguments (2 given)

What parameter need to be passed in the radio button in order to avoid this error

回答1:

Looking at the source, it looks like you have to use one Radio constructor for all of your items as the same Radio object will actually generate multiple <input> elements.

Try something like::

project_details = form.Form( 
    form.Radio('details', ['Home Page', 'Content', 'Contact Us', 'Sitemap']),
    )

回答2:

Here's what I was able to decipher. checked='checked' seems to select a random (last?) item in the list. Without a default selection, my testing was coming back with a NoneType, if none of the radio-buttons got selected.

project_details = form.Form(
  form.Radio('selections', ['Home Page', 'Content', 'Contact Us','Sitemap'], checked='checked'),
  form.Button("Submit") 
)

To access your user selection as a string...

result = project_details['selections'].value

If you want to use javascript while your template is active, you can add, onchange='myFunction()' to the end of the Radio line-item. I'm also assigning an id for each element, to avoid frustration with my getElementById calls, so my declaration looks like this.

 project_details = form.Form(
   form.Radio('selections', ['Home Page', 'Content', 'Contact Us','Sitemap'], checked='checked', onchange='myFunction()', id='selections'),
   form.Button("Submit") 
)