Question

I’ve a little doubt for writing a Python application follow the MVC rules on wxPython.

Example:

MainForm

PanelLst (ListCtrl + Some buttons)

PanelTree (TreeCtrl + ProgressBar)

I created 3 views (ListView, TreeView, ButtonView)
I created also 3 controllers (ListController, TreeController, ButtonControllor)
In the main app, I have an object (objManager) that manage some models.

All 3 controllers have a pointer to the App.objManager() for executing some stuff.

Eg: click on a row in ListController execute App.objManager().foo1

click on a button in ButtonController execute App.objManager().bar1, ecc…

Here the question…I’m in doubt about those “my” structure…

1. is correct pass a pointer to objManager in each controller that use that?
2. how View/Controllers can communicate between others, in correct way?
   Actually I use a similar way like model. Using wxPython publisher.sendMessage(EVENT, data) and publisher.subscribe(EVENT, onEvent) but I think isn’t the best way..

Next doubt:

TreeController, receive a message from a model. Must load a big list in the tree, showing progress.
I already user a thread with some wx.PostEvent, but what solution is better?

Solution 1:

ProgressBar()

# Callback via publisher.subscrive(self.onUpdateStatus, "UPDATE_STATUS")
def onUpdateStatus(self, msg)
    nValue = msg.data
    self.gauge.setValue(nValue)

TreeView()

def loadTree(self, items):
    for nItem, item in enumerate(items):
        tree.addItem(item)
        pub.sendMessage(UPDATE_STATUS, item)

TreeCTRL()

 # Callback function via publisher.subscribe(self.onLoadTree, "LOAD_TREE")
 def onLoadTree():
     items = self.objManager.getList()
     self.hTreeView.loadTree(items)

Solution 2

ProgressBar()

# Callback via publisher.subscrive(self.onUpdateStatus, "UPDATE_STATUS")
def onUpdateStatus(self, msg)
    nValue = msg.data
    self.gauge.setValue(nValue)

TreeView()

def loadTree(self, item):
    self.addTreeItem(item)

TreeCTRL()

 # Callback function via publisher.subscribe(self.onLoadTree, "LOAD_TREE")
 def onLoadTree():
     items = self.objManager.getList()
     for nItem, item in enumerate(items):
         self.hTreeView.loadTree(item)
         pub.sendMessage(UPDATE_STATUS, item)

What solution is better? In first solution, is the VIEW that send a message for updating the GUI. In second solution is the CONTROLLER that send a message..
Not sure that those 2 solution is anyway the best-practice for communicating between controller/view..

Thanks and sorry for my bad English…

Answer 1

I think using pubsub is a perfectly legitimate way to communicate between the model and the controllers. A couple months ago, I worked with another wxPython developer to create an example application that demonstrates one way to do this. You can see our code here: https://bitbucket.org/driscollis/medialocker

I hope that helps you organize your code. Of course, code design is a very personal and subjective topic. You need to use what you’re comfortable with and understand best.