Python GtkTreeview; How to refresh the list when an item is selected

I'm making a rudimentary file manager and am stuck on the question in my post's title. First it looks in a directory, generates a list of items, and appends them to the treeview list.

If a subdirectory is clicked, it becomes the new current directory. All I need is to send this back into the def where it reads and display the current directories contents (I think).

    import gtk, os

    class PyApp(gtk.Window): 
        def __init__(self):
            super(PyApp, self).__init__()
            self.set_size_request(250, 200)
            self.set_position(gtk.WIN_POS_CENTER)
            self.connect("destroy", gtk.main_quit)
            self.set_title("SteveFM")
            vbox = gtk.VBox(False, 8)
            sw = gtk.ScrolledWindow()
            sw.set_shadow_type(gtk.SHADOW_ETCHED_IN)
            sw.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC)
            vbox.pack_start(sw, True, True, 0)
            store = self.create_model()
            treeView = gtk.TreeView(store)
            treeView.connect("row-activated", self.on_activated)
            treeView.set_rules_hint(True)
            sw.add(treeView)
            self.create_columns(treeView)        
            self.add(vbox)
            self.show_all()

        #  Take the names of files and subdirectories in 
        #  the current directory and sort them into a list for treeview

        def create_model(self):
            store = gtk.ListStore(str)
            dirList=os.listdir(os.getcwd())
            dircontents = []
            for item in dirList: 
                if item[0] != '.':
                    if os.path.isdir(item):
                        dircontents.append(['/'+item])
                    else:
                        dircontents.append([item])
            dircontents.sort() 
            for act in dircontents:
                store.append([act[0]])
            return store

        #  If a file is clicked, open with leafpad.
        #  If开发者_运维技巧 a directory is clicked, change the current working directory to it
        #  and (my hurdle) replace the current treeview list with the contents of the 
        #  new directory, just like a file manager.

        def on_activated(self, widget, row, col):
            model = widget.get_model()
            target = model[row][0]
            if target[0] != "/":
                cmd = "leafpad "+target
                os.system(cmd)
            else:
                os.chdir(os.getcwd()+target)
                print os.getcwd()   # Just for debugging

        def create_columns(self, treeView):
            rendererText = gtk.CellRendererText()
            column = gtk.TreeViewColumn(None, rendererText, text=0)
            column.set_sort_column_id(0)    
            treeView.append_column(column)     

PyApp() 
gtk.main()

Changes I made:

1. Replace treeView with self.treeView so I can access it easily in other methods.

2. In on_activated, create a new model with create_model, and set self.treeView to use that model using gtk.TreeView.set_model.

It seems to work. Code:

import gtk, os

class PyApp(gtk.Window): 
    def __init__(self):
        super(PyApp, self).__init__()
        self.set_size_request(250, 200)
        self.set_position(gtk.WIN_POS_CENTER)
        self.connect("destroy", gtk.main_quit)
        self.set_title("SteveFM")
        vbox = gtk.VBox(False, 8)
        sw = gtk.ScrolledWindow()
        sw.set_shadow_type(gtk.SHADOW_ETCHED_IN)
        sw.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC)
        vbox.pack_start(sw, True, True, 0)
        store = self.create_model()
        self.treeView = gtk.TreeView(store)
        self.treeView.connect("row-activated", self.on_activated)
        self.treeView.set_rules_hint(True)
        sw.add(self.treeView)
        self.create_columns(self.treeView)        
        self.add(vbox)
        self.show_all()

    #  Take the names of files and subdirectories in 
    #  the current directory and sort them into a list for treeview

    def create_model(self):
        store = gtk.ListStore(str)
        dirList=os.listdir(os.getcwd())
        dircontents = []
        for item in dirList: 
            if item[0] != '.':
                if os.path.isdir(item):
                    dircontents.append(['/'+item])
                else:
                    dircontents.append([item])
        dircontents.sort() 
        for act in dircontents:
            store.append([act[0]])
        return store

    #  If a file is clicked, open with leafpad.
    #  If a directory is clicked, change the current working directory to it
    #  and (my hurdle) replace the current treeview list with the contents of the 
    #  new directory, just like a file manager.

    def on_activated(self, widget, row, col):
        model = widget.get_model()
        target = model[row][0]
        if target[0] != "/":
            cmd = "leafpad "+target
            os.system(cmd)
        else:
            os.chdir(os.getcwd()+target)
            print os.getcwd()   # Just for debugging
            self.treeView.set_model(self.create_model())

    def create_columns(self, treeView):
        rendererText = gtk.CellRendererText()
        column = gtk.TreeViewColumn(None, rendererText, text=0)
        column.set_sort_column_id(0)    
        self.treeView.append_column(column)     

PyApp() 
gtk.main()