Added 'Button' type to build ViewItem objects, for embedding buttons with custom callbacks.

tkprop/build.py

@@ -72,7 +72,17 @@ class ViewItem(object):
 
         self.visibleWhen = visibleWhen
         self.enabledWhen = enabledWhen
- 
+
+
+class Button(ViewItem):
+    """
+    Represents a button which, when clicked, willl call a specified
+    callback function.
+    """
+
+    def __init__(self, callback=None, **kwargs):
+        self.callback = callback
+        ViewItem.__init__(self, **kwargs)
 
 
 class Widget(ViewItem):
@@ -222,6 +232,15 @@ def _createLabel(parent, viewItem, propObj):
     return label
 
 
+def _createButton(parent, widget):
+    """
+    Creates a ttk.Button object for the given Button widget.
+    """
+
+    button = ttk.Button(parent, text=widget.label, command=widget.callback)
+    return button
+
+
 def _createWidget(parent, widget, propObj):
     """
     Creates a widget for the given Widget object, using the
@@ -353,6 +372,9 @@ def _create(parent, viewItem, propObj):
 
     if isinstance(viewItem, Widget):
         return _createWidget(parent, viewItem, propObj)
+
+    elif isinstance(viewItem, Button):
+        return _createButton(parent, viewItem)
         
     elif isinstance(viewItem, NotebookGroup):
         return _createNotebookGroup(parent, viewItem, propObj)

tkprop/properties.py

@@ -77,6 +77,7 @@ import os.path as op
 
 import Tkinter as tk
 
+#
 # The classes below are used in place of the Tkinter.*Var classes.
 # They are identical to the Tkinter versions, with the following
 # exceptions:
@@ -88,7 +89,13 @@ import Tkinter as tk
 #      PropertyBase.validate method is called, to test that
 #      the new value is valid. If the new value is not valid,
 #      a ValueError is raised.
-
+#
+# NOTE TO SELF: Another way that I could provide this callback
+# functionality is to simply use the trace feature of Tkinter
+# variables. I'd need to come up with some sort of mechanism
+# for reverting to a previous value for invalid writes, though.
+# Better? Worse? I don't know.
+#
 class _StringVar(tk.StringVar):
     def __init__(self, tkProp, **kwargs):
         self.tkProp = tkProp