I'm still learning Python, so I tried to build a basic MVC app using wxPython and pubsub. While it seems to work fine, the code seems to be getting out of hand.
In model I decided against using traditional (e.g. Java) accessors and went with the more Pythonic approach of properties. I only wanted to set the setters, but ended up needing to set the getters too (because the variable name had to change to prevent recursion). What's the preferred way to do this?
Next, the flow for setting each variable seems a mess. Right now, changing the name in view publishes a message which controller is subscribed to, so it sets the name in model, which publisher another message which controller is subscribed to, which sends a message to view, which finally does something with the values (the last part is not really required at the moment, but should be in many cases). Is this all peachy, or am I missing something?
As for any other blunders, I'd be happy to hear them!
I mostly followed Mike Rooney's Code Sample.
"""
A simple attempt at a pubsub-driven MVC application with wxPython
"""
import wx
import wx.lib.pubsub
# this seems to be required -- bug?
pub = wx.lib.pubsub.Publisher()
class Model(object):
def __init__(self, name, age):
self._name = name
self._age = age
@property
def name(self):
return self._name
@name.setter
def name(self, value):
self._name = value
pub.sendMessage("name.changed", self.name)
@property
def age(self):
return self._age
@age.setter
def age(self, value):
self._age = value
pub.sendMessage("age.changed", self.age)
class View(wx.Frame):
def __init__(self, parent):
wx.Frame.__init__(self, parent, title="MVC test", size=(200, 150))
# setup sizers
self.padding_sizer = wx.BoxSizer(wx.HORIZONTAL)
self.sizer = wx.FlexGridSizer(2, 2, 8, 25)
self.sizer.AddGrowableCol(1, 1) # make the second column fit available space
self.padding_sizer.Add(self.sizer, proportion=1, flag=wx.ALL|wx.EXPAND, border=14)
self.SetSizer(self.padding_sizer)
# setup widgets
# name
self.name_label = wx.StaticText(self, label="Name:")
self.name = wx.TextCtrl(self, style=wx.TE_PROCESS_ENTER)
self.sizer.Add(self.name_label)
self.sizer.Add(self.name, 1, wx.EXPAND)
# age
self.age_label = wx.StaticText(self, label="Age:")
self.age = wx.TextCtrl(self, style=wx.TE_PROCESS_ENTER)
self.sizer.Add(self.age_label)
self.sizer.Add(self.age, 1, wx.EXPAND)
# setters for wx controls
def set_name(self, name):
self.name.SetValue(name)
def set_age(self, age):
self.age.SetValue(str(age))
class Controller(object):
def __init__(self, app):
# controller holds refs to models, app and views
self.model = Model('Goku', 9001)
self.app = app
self.view = View(None)
# set up the view
self.view.set_name(self.model.name)
self.view.set_age(self.model.age)
# bind view events to methods
self.view.name.Bind(wx.EVT_TEXT_ENTER, self.change_name)
self.view.age.Bind(wx.EVT_TEXT_ENTER, self.change_age)
# subscriptions
pub.subscribe(self.name_changed, "name.changed")
pub.subscribe(self.age_changed, "age.changed")
# finally,show the view
self.view.Show()
def change_name(self, evt):
self.model.name = evt.String
print "Name was changed to", self.model.name
def name_changed(self, message):
# unnecessary at the moment, for illustration only
self.view.set_name(message.data)
def change_age(self, evt):
self.model.age = int(evt.String)
print "Age was changed to", self.model.age
def age_changed(self, message):
# unnecessary at the moment, for illustration only
self.view.set_age(message.data)
if __name__ == '__main__':
#create the wx app
app = wx.App(False)
# pass the app to the controller
controller = Controller(app)
# start the app running
app.MainLoop()