The following implements a Poll product (add it as zope/app/demo/poll) which has poll options defined as:
Simple stuff.
Our Poll product holds an editable list of the PollOption instances. This is shown in the poll.py source below:
from persistent import Persistent from interfaces import IPoll, IPollOption from zope.interface import implements, classImplements class PollOption(Persistent, object): implements(IPollOption) class Poll(Persistent, object): implements(IPoll) def getResponse(self, option): return self._responses[option] def choose(self, option): self._responses[option] += 1 self._p_changed = 1 def get_options(self): return self._options def set_options(self, options): self._options = options self._responses = {} for option in self._options: self._responses[option.label] = 0 options = property(get_options, set_options, None, 'fiddle options')
And the Schemas are defined in the interfaces.py file below:
from zope.interface import Interface from zope.schema import Object, Tuple, TextLine from zope.schema.interfaces import ITextLine from zope.i18nmessageid import MessageFactory _ = MessageFactory("poll") class IPollOption(Interface): label = TextLine(title=u'Label', min_length=1) description = TextLine(title=u'Description', min_length=1) class IPoll(Interface): options = Tuple(title=u'Options', value_type=Object(IPollOption, title=u'Poll Option')) def getResponse(option): "get the response for an option" def choose(option): 'user chooses an option'
Note the use of the Tuple and Object schema fields above. The Tuple could optionally have restrictions on the min or max number of items - these will be enforced by the SequenceWidget form handling code. The Object must specify the schema that is used to generate its data.
Now we have to specify the actual add and edit views. We use the existing AddView and EditView, but we pre-define the widget for the sequence because we need to pass in additional information. This is given in the browser.py file:
from zope.app.form.browser.editview import EditView from zope.app.form.browser.add import AddView from zope.app.form import CustomWidgetFactory from zope.app.form.browser import SequenceWidget, ObjectWidget from interfaces import IPoll from poll import Poll, PollOption class PollVoteView: __used_for__ = IPoll def choose(self, option): self.context.choose(option) self.request.response.redirect('.') ow = CustomWidgetFactory(ObjectWidget, PollOption) sw = CustomWidgetFactory(SequenceWidget, subwidget=ow) class PollEditView(EditView): __used_for__ = IPoll options_widget = sw class PollAddView(AddView): __used_for__ = IPoll options_widget = sw
Note the creation of the widget via a CustomWidgetFactory. So, whenever the options_widget is used, a new SequenceWidget(subwidget=CustomWidgetFactory(ObjectWidget, PollOption)) is created. The subwidget argument indicates that each item in the sequence should be represented by the indicated widget instead of their default. If the contents of the sequence were just Text fields, then the default would be just fine - the only odd cases are Sequence and Object Widgets because they need additional arguments when they're created.
Each item in the sequence will be represented by a CustomWidgetFactory(ObjectWidget, PollOption) - thus a new ObjectWidget(context, request, PollOption) is created for each one. The PollOption class ("factory") is used to create new instances when new data is created in add forms (or edit forms when we're adding new items to a Sequence).
Tying all this together is the configure.zcml:
<configure xmlns='http://namespaces.zope.org/zope' xmlns:browser='http://namespaces.zope.org/browser'> <content class=".poll.Poll"> <factory id="zope.app.demo.poll" permission="zope.ManageContent" /> <implements interface="zope.annotation.interfaces.IAttributeAnnotatable" /> <require permission="zope.View" interface=".interfaces.IPoll" /> <require permission="zope.ManageContent" set_schema=".interfaces.IPoll" /> </content> <content class=".poll.PollOption"> <require permission="zope.View" interface=".interfaces.IPollOption" /> </content> <browser:page for=".interfaces.IPoll" name="index.html" template="results.zpt" permission="zope.View" menu="zmi_views" title="View" /> <browser:pages for=".interfaces.IPoll" class=".browser.PollVoteView" permission="zope.ManageContent"> <browser:page name="vote.html" template="vote.zpt" menu="zmi_views" title="Vote" /> <browser:page name="choose" attribute="choose" /> </browser:pages> <browser:addform schema=".interfaces.IPoll" label="Add a Poll" content_factory=".poll.Poll" name="AddPoll.html" class=".browser.PollAddView" permission="zope.ManageContent" /> <browser:addMenuItem title="Poll Demo" description="Poll Demo" content_factory=".poll.Poll" view="AddPoll.html" permission="zope.ManageContent" /> <browser:editform schema=".interfaces.IPoll" class=".browser.PollEditView" label="Change a Poll" name="edit.html" menu="zmi_views" title="Edit" permission="zope.ManageContent" /> </configure>
Note the use of the class attribute on the addform and editform elements. Otherwise, nothing much exciting here.
Finally, we have some additional views...
results.zpt:
<html metal:use-macro="context/@@standard_macros/page"> <title metal:fill-slot="title">Poll results</title> <div metal:fill-slot="body"> <table border="1"> <caption>Poll results</caption> <thead> <tr><th>Option</th><th>Results</th><th>Description</th></tr> </thead> <tbody> <tr tal:repeat="option context/options"> <td tal:content="option/label">Option</td> <td tal:content="python:context.getResponse(option.label)">Result</td> <td tal:content="option/description">Option</td> </tr> </tbody> </table> </div> </html>
vote.zpt:
<html metal:use-macro="context/@@standard_macros/page"> <title metal:fill-slot="title">Poll voting</title> <div metal:fill-slot="body"> <form action="choose"> <table border="1"> <caption>Poll voting</caption> <tbody> <tr tal:repeat="option context/options"> <td><input type="radio" name="option" tal:attributes="value option/label"></td> <td tal:content="option/label">Option</td> <td tal:content="option/description">Option</td> </tr> </tbody> </table> <input type="submit"> </form> </div> </html>