Changed on_submit to use custom messages instead of stateful communcation

IPython/html/static/notebook/js/widgets/string.js

@@ -151,8 +151,8 b' define(["notebook/js/widget"], function(widget_manager){'
         // Handles text submition
         handleKeypress: function(e) { 
             if (e.keyCode == 13) { // Return key
-                this.model.set('submits', this.model.get('submits') + 1);
-                this.model.update_other_views(this);
+                this.model.last_modified_view = this; // For callbacks.
+                this.model.send({event: 'submit'});
             }
         },
     });

IPython/html/widgets/widget_string.py

@@ -27,23 +27,52 b' class StringWidget(Widget):'
     default_view_name = Unicode('TextBoxView')
 
     # Keys
-    _keys = ['value', 'disabled', 'description', 'submits', 'scroll_to_bottoms']
+    _keys = ['value', 'disabled', 'description', 'scroll_to_bottoms']
     value = Unicode(help="String value")
     disabled = Bool(False, help="Enable or disable user changes")
     description = Unicode(help="Description of the value this widget represents")
-    submits = Int(0, help="Used to capture and fire submission ")
     scroll_to_bottoms = Int(0, help="Used to scroll a TextAreaView to the bottom")
 
 
     def __init__(self, **kwargs):
         super(StringWidget, self).__init__(**kwargs)
-        self._submission_callbacks = []
+        self._submission_callbacks = []        
+        self.on_msg(self._handle_string_msg)
 
 
     def scroll_to_bottom(self):
         self.scroll_to_bottoms += 1
 
 
+    def on_click(self, callback, remove=False):
+        """Register a callback to execute when the button is clicked.  The
+        callback can either accept no parameters or one sender parameter:
+        - callback()
+        - callback(sender)
+        If the callback has a sender parameter, the ButtonWidget instance that
+        called the callback will be passed into the method as the sender.
+
+        Parameters
+        ----------
+        remove : bool (optional)
+            Set to true to remove the callback from the list of callbacks."""
+        if remove:
+            self._click_handlers.remove(callback)
+        elif not callback in self._click_handlers:
+            self._click_handlers.append(callback)
+
+
+    def _handle_string_msg(self, content):
+        """Handle a msg from the front-end
+
+        Parameters
+        ----------
+        content: dict
+            Content of the msg."""
+        if 'event' in content and content['event'] == 'submit':
+            self._handle_submit()
+
+
     def on_submit(self, callback, remove=False):
         """Register a callback to handle text submission (triggered when the 
         user clicks enter).
@@ -62,23 +91,22 b' class StringWidget(Widget):'
             self._submission_callbacks.append(callback)
 
 
-    def _submits_changed(self, name, old_value, new_value):
+    def _handle_submit(self):
         """Handles when a string widget view is submitted."""
-        if new_value > old_value:
-            for handler in self._submission_callbacks:
-                if callable(handler):
-                    argspec = inspect.getargspec(handler)
-                    nargs = len(argspec[0])
-
-                    # Bound methods have an additional 'self' argument
-                    if isinstance(handler, types.MethodType):
-                        nargs -= 1
-
-                    # Call the callback
-                    if nargs == 0:
-                        handler()
-                    elif nargs == 1:
-                        handler(self)
-                    else:
-                        raise TypeError('StringWidget submit callback must ' \
-                            'accept 0 or 1 arguments.')
+        for handler in self._submission_callbacks:
+            if callable(handler):
+                argspec = inspect.getargspec(handler)
+                nargs = len(argspec[0])
+
+                # Bound methods have an additional 'self' argument
+                if isinstance(handler, types.MethodType):
+                    nargs -= 1
+
+                # Call the callback
+                if nargs == 0:
+                    handler()
+                elif nargs == 1:
+                    handler(self)
+                else:
+                    raise TypeError('StringWidget submit callback must ' \
+                        'accept 0 or 1 arguments.')