Implement view logic in selection containers.

IPython/html/static/widgets/js/widget.js

@@ -1,683 +1,681
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define(["widgets/js/manager",
         "underscore",
         "backbone",
         "jquery",
         "base/js/utils",
         "base/js/namespace",
 ], function(widgetmanager, _, Backbone, $, utils, IPython){
 
     var WidgetModel = Backbone.Model.extend({
         constructor: function (widget_manager, model_id, comm) {
             // Constructor
             //
             // Creates a WidgetModel instance.
             //
             // Parameters
             // ----------
             // widget_manager : WidgetManager instance
             // model_id : string
             //      An ID unique to this model.
             // comm : Comm instance (optional)
             this.widget_manager = widget_manager;
             this.state_change = Promise.resolve();
             this._buffered_state_diff = {};
             this.pending_msgs = 0;
             this.msg_buffer = null;
             this.state_lock = null;
             this.id = model_id;
             this.views = {};
 
             if (comm !== undefined) {
                 // Remember comm associated with the model.
                 this.comm = comm;
                 comm.model = this;
 
                 // Hook comm messages up to model.
                 comm.on_close($.proxy(this._handle_comm_closed, this));
                 comm.on_msg($.proxy(this._handle_comm_msg, this));
             }
             return Backbone.Model.apply(this);
         },
 
         send: function (content, callbacks) {
             // Send a custom msg over the comm.
             if (this.comm !== undefined) {
                 var data = {method: 'custom', content: content};
                 this.comm.send(data, callbacks);
                 this.pending_msgs++;
             }
         },
 
         _handle_comm_closed: function (msg) {
             // Handle when a widget is closed.
             this.trigger('comm:close');
             this.stopListening();
             this.trigger('destroy', this);
             delete this.comm.model; // Delete ref so GC will collect widget model.
             delete this.comm;
             delete this.model_id; // Delete id from model so widget manager cleans up.
             for (var id in this.views) {
                 if (this.views.hasOwnProperty(id)) {
                     this.views[id].remove();
                 }
             }
         },
 
         _handle_comm_msg: function (msg) {
             // Handle incoming comm msg.
             var method = msg.content.data.method;
             var that = this;
             switch (method) {
                 case 'update':
                     this.state_change = this.state_change.then(function() {
                         return that.set_state(msg.content.data.state);
                     }).catch(utils.reject("Couldn't process update msg for model id '" + String(that.id) + "'", true));
                     break;
                 case 'custom':
                     this.trigger('msg:custom', msg.content.data.content);
                     break;
                 case 'display':
                     this.widget_manager.display_view(msg, this);
                     break;
             }
         },
 
         set_state: function (state) {
             var that = this;
             // Handle when a widget is updated via the python side.
             return this._unpack_models(state).then(function(state) {
                 that.state_lock = state;
                 try {
                     WidgetModel.__super__.set.call(that, state);
                 } finally {
                     that.state_lock = null;
                 }
             }, utils.reject("Couldn't set model state", true));
         },
 
         _handle_status: function (msg, callbacks) {
             // Handle status msgs.
 
             // execution_state : ('busy', 'idle', 'starting')
             if (this.comm !== undefined) {
                 if (msg.content.execution_state ==='idle') {
                     // Send buffer if this message caused another message to be
                     // throttled.
                     if (this.msg_buffer !== null &&
                         (this.get('msg_throttle') || 3) === this.pending_msgs) {
                         var data = {method: 'backbone', sync_method: 'update', sync_data: this.msg_buffer};
                         this.comm.send(data, callbacks);
                         this.msg_buffer = null;
                     } else {
                         --this.pending_msgs;
                     }
                 }
             }
         },
 
         callbacks: function(view) {
             // Create msg callbacks for a comm msg.
             var callbacks = this.widget_manager.callbacks(view);
 
             if (callbacks.iopub === undefined) {
                 callbacks.iopub = {};
             }
 
             var that = this;
             callbacks.iopub.status = function (msg) {
                 that._handle_status(msg, callbacks);
             };
             return callbacks;
         },
 
         set: function(key, val, options) {
             // Set a value.
             var return_value = WidgetModel.__super__.set.apply(this, arguments);
 
             // Backbone only remembers the diff of the most recent set()
             // operation.  Calling set multiple times in a row results in a 
             // loss of diff information.  Here we keep our own running diff.
             this._buffered_state_diff = $.extend(this._buffered_state_diff, this.changedAttributes() || {});
             return return_value;
         },
 
         sync: function (method, model, options) {
             // Handle sync to the back-end.  Called when a model.save() is called.
 
             // Make sure a comm exists.
             var error = options.error || function() {
                 console.error('Backbone sync error:', arguments);
             };
             if (this.comm === undefined) {
                 error();
                 return false;
             }
 
             // Delete any key value pairs that the back-end already knows about.
             var attrs = (method === 'patch') ? options.attrs : model.toJSON(options);
             if (this.state_lock !== null) {
                 var keys = Object.keys(this.state_lock);
                 for (var i=0; i<keys.length; i++) {
                     var key = keys[i];
                     if (attrs[key] === this.state_lock[key]) {
                         delete attrs[key];
                     }
                 }
             }
 
             // Only sync if there are attributes to send to the back-end.
             attrs = this._pack_models(attrs);
             if (_.size(attrs) > 0) {
 
                 // If this message was sent via backbone itself, it will not
                 // have any callbacks.  It's important that we create callbacks
                 // so we can listen for status messages, etc...
                 var callbacks = options.callbacks || this.callbacks();
 
                 // Check throttle.
                 if (this.pending_msgs >= (this.get('msg_throttle') || 3)) {
                     // The throttle has been exceeded, buffer the current msg so
                     // it can be sent once the kernel has finished processing 
                     // some of the existing messages.
                     
                     // Combine updates if it is a 'patch' sync, otherwise replace updates
                     switch (method) {
                         case 'patch':
                             this.msg_buffer = $.extend(this.msg_buffer || {}, attrs);
                             break;
                         case 'update':
                         case 'create':
                             this.msg_buffer = attrs;
                             break;
                         default:
                             error();
                             return false;
                     }
                     this.msg_buffer_callbacks = callbacks;
 
                 } else {
                     // We haven't exceeded the throttle, send the message like 
                     // normal.
                     var data = {method: 'backbone', sync_data: attrs};
                     this.comm.send(data, callbacks);
                     this.pending_msgs++;
                 }
             }
             // Since the comm is a one-way communication, assume the message 
             // arrived.  Don't call success since we don't have a model back from the server
             // this means we miss out on the 'sync' event.
             this._buffered_state_diff = {};
         },
 
         save_changes: function(callbacks) {
             // Push this model's state to the back-end
             //
             // This invokes a Backbone.Sync.
             this.save(this._buffered_state_diff, {patch: true, callbacks: callbacks});
         },
 
         _pack_models: function(value) {
             // Replace models with model ids recursively.
             var that = this;
             var packed;
             if (value instanceof Backbone.Model) {
                 return "IPY_MODEL_" + value.id;
 
             } else if ($.isArray(value)) {
                 packed = [];
                 _.each(value, function(sub_value, key) {
                     packed.push(that._pack_models(sub_value));
                 });
                 return packed;
             } else if (value instanceof Date || value instanceof String) {
                 return value;
             } else if (value instanceof Object) {
                 packed = {};
                 _.each(value, function(sub_value, key) {
                     packed[key] = that._pack_models(sub_value);
                 });
                 return packed;
 
             } else {
                 return value;
             }
         },
 
         _unpack_models: function(value) {
             // Replace model ids with models recursively.
             var that = this;
             var unpacked;
             if ($.isArray(value)) {
                 unpacked = [];
                 _.each(value, function(sub_value, key) {
                     unpacked.push(that._unpack_models(sub_value));
                 });
                 return Promise.all(unpacked);
             } else if (value instanceof Object) {
                 unpacked = {};
                 _.each(value, function(sub_value, key) {
                     unpacked[key] = that._unpack_models(sub_value);
                 });
                 return utils.resolve_promises_dict(unpacked);
             } else if (typeof value === 'string' && value.slice(0,10) === "IPY_MODEL_") {
                 // get_model returns a promise already
                 return this.widget_manager.get_model(value.slice(10, value.length));
             } else {
                 return Promise.resolve(value);
             }
         },
 
         on_some_change: function(keys, callback, context) {
             // on_some_change(["key1", "key2"], foo, context) differs from
             // on("change:key1 change:key2", foo, context).
             // If the widget attributes key1 and key2 are both modified, 
             // the second form will result in foo being called twice
             // while the first will call foo only once.
             this.on('change', function() {
                 if (keys.some(this.hasChanged, this)) {
                     callback.apply(context);
                 }
             }, this);
 
        },
     });
     widgetmanager.WidgetManager.register_widget_model('WidgetModel', WidgetModel);
 
 
     var WidgetView = Backbone.View.extend({
         initialize: function(parameters) {
             // Public constructor.
             this.model.on('change',this.update,this);
             this.options = parameters.options;
             this.child_model_views = {};
             this.child_views = {};
             this.id = this.id || utils.uuid();
             this.model.views[this.id] = this;
             this.on('displayed', function() { 
                 this.is_displayed = true; 
             }, this);
         },
 
         update: function(){
             // Triggered on model change.
             //
             // Update view to be consistent with this.model
         },
 
         create_child_view: function(child_model, options) {
             // Create and promise that resolves to a child view of a given model
             var that = this;
             options = $.extend({ parent: this }, options || {});
             return this.model.widget_manager.create_view(child_model, options).then(function(child_view) {
                 // Associate the view id with the model id.
                 if (that.child_model_views[child_model.id] === undefined) {
                     that.child_model_views[child_model.id] = [];
                 }
                 that.child_model_views[child_model.id].push(child_view.id);
                 // Remember the view by id.
                 that.child_views[child_view.id] = child_view;
                 return child_view;
             }, utils.reject("Couldn't create child view"));
         },
 
         pop_child_view: function(child_model) {
             // Delete a child view that was previously created using create_child_view.
             console.error("Deprecated pop_child_view; use a ViewList or similar class instead");
             var view_ids = this.child_model_views[child_model.id];
             if (view_ids !== undefined) {
 
                 // Only delete the first view in the list.
                 var view_id = view_ids[0];
                 var view = this.child_views[view_id];
                 delete this.child_views[view_id];
                 view_ids.splice(0,1);
                 delete child_model.views[view_id];
             
                 // Remove the view list specific to this model if it is empty.
                 if (view_ids.length === 0) {
                     delete this.child_model_views[child_model.id];
                 }
                 return view;
             }
             return null;
         },
 
         do_diff: function(old_list, new_list, removed_callback, added_callback) {
             // Difference a changed list and call remove and add callbacks for 
             // each removed and added item in the new list.
             //
             // Parameters
             // ----------
             // old_list : array
             // new_list : array
             // removed_callback : Callback(item)
             //      Callback that is called for each item removed.
             // added_callback : Callback(item)
             //      Callback that is called for each item added.
 
             // Walk the lists until an unequal entry is found.
-            console.error("Deprecated _do_diff; use a ViewList or similar class instead");
-
             var i;
             for (i = 0; i < new_list.length; i++) {
                 if (i >= old_list.length || new_list[i] !== old_list[i]) {
                     break;
                 }
             }
 
             // Remove the non-matching items from the old list.
             for (var j = i; j < old_list.length; j++) {
                 removed_callback(old_list[j]);
             }
 
             // Add the rest of the new list items.
             for (; i < new_list.length; i++) {
                 added_callback(new_list[i]);
             }
         },
 
         callbacks: function(){
             // Create msg callbacks for a comm msg.
             return this.model.callbacks(this);
         },
 
         render: function(){
             // Render the view.
             //
             // By default, this is only called the first time the view is created
         },
 
         show: function(){
             // Show the widget-area
             if (this.options && this.options.cell &&
                 this.options.cell.widget_area !== undefined) {
                 this.options.cell.widget_area.show();
             }
         },
 
         send: function (content) {
             // Send a custom msg associated with this view.
             this.model.send(content, this.callbacks());
         },
 
         touch: function () {
             this.model.save_changes(this.callbacks());
         },
 
         after_displayed: function (callback, context) {
             // Calls the callback right away is the view is already displayed
             // otherwise, register the callback to the 'displayed' event.
             if (this.is_displayed) {
                 callback.apply(context);
             } else {
                 this.on('displayed', callback, context);
             }
         },
     });
 
 
     var DOMWidgetView = WidgetView.extend({
         initialize: function (parameters) {
             // Public constructor
             DOMWidgetView.__super__.initialize.apply(this, [parameters]);
             this.on('displayed', this.show, this);
             this.model.on('change:visible', this.update_visible, this);
             this.model.on('change:_css', this.update_css, this);
 
             this.model.on('change:_dom_classes', function(model, new_classes) {
                 var old_classes = model.previous('_dom_classes');
                 this.update_classes(old_classes, new_classes);
             }, this);
 
             this.model.on('change:color', function (model, value) { 
                 this.update_attr('color', value); }, this);
 
             this.model.on('change:background_color', function (model, value) { 
                 this.update_attr('background', value); }, this);
 
             this.model.on('change:width', function (model, value) { 
                 this.update_attr('width', value); }, this);
 
             this.model.on('change:height', function (model, value) { 
                 this.update_attr('height', value); }, this);
 
             this.model.on('change:border_color', function (model, value) { 
                 this.update_attr('border-color', value); }, this);
 
             this.model.on('change:border_width', function (model, value) { 
                 this.update_attr('border-width', value); }, this);
 
             this.model.on('change:border_style', function (model, value) { 
                 this.update_attr('border-style', value); }, this);
 
             this.model.on('change:font_style', function (model, value) { 
                 this.update_attr('font-style', value); }, this);
 
             this.model.on('change:font_weight', function (model, value) { 
                 this.update_attr('font-weight', value); }, this);
 
             this.model.on('change:font_size', function (model, value) { 
                 this.update_attr('font-size', this._default_px(value)); }, this);
 
             this.model.on('change:font_family', function (model, value) { 
                 this.update_attr('font-family', value); }, this);
 
             this.model.on('change:padding', function (model, value) { 
                 this.update_attr('padding', value); }, this);
 
             this.model.on('change:margin', function (model, value) { 
                 this.update_attr('margin', this._default_px(value)); }, this);
 
             this.model.on('change:border_radius', function (model, value) { 
                 this.update_attr('border-radius', this._default_px(value)); }, this);
 
             this.after_displayed(function() {
                 this.update_visible(this.model, this.model.get("visible"));
                 this.update_classes([], this.model.get('_dom_classes'));
                 
                 this.update_attr('color', this.model.get('color'));
                 this.update_attr('background', this.model.get('background_color'));
                 this.update_attr('width', this.model.get('width'));
                 this.update_attr('height', this.model.get('height'));
                 this.update_attr('border-color', this.model.get('border_color'));
                 this.update_attr('border-width', this.model.get('border_width'));
                 this.update_attr('border-style', this.model.get('border_style'));
                 this.update_attr('font-style', this.model.get('font_style'));
                 this.update_attr('font-weight', this.model.get('font_weight'));
                 this.update_attr('font-size', this.model.get('font_size'));
                 this.update_attr('font-family', this.model.get('font_family'));
                 this.update_attr('padding', this.model.get('padding'));
                 this.update_attr('margin', this.model.get('margin'));
                 this.update_attr('border-radius', this.model.get('border_radius'));
 
                 this.update_css(this.model, this.model.get("_css"));
             }, this);
         },
 
         _default_px: function(value) {
             // Makes browser interpret a numerical string as a pixel value.
             if (/^\d+\.?(\d+)?$/.test(value.trim())) {
                 return value.trim() + 'px';
             }
             return value;
         },
 
         update_attr: function(name, value) {
             // Set a css attr of the widget view.
             this.$el.css(name, value);
         },
 
         update_visible: function(model, value) {
             // Update visibility
             this.$el.toggle(value);
          },
 
         update_css: function (model, css) {
             // Update the css styling of this view.
             var e = this.$el;
             if (css === undefined) {return;}
             for (var i = 0; i < css.length; i++) {
                 // Apply the css traits to all elements that match the selector.
                 var selector = css[i][0];
                 var elements = this._get_selector_element(selector);
                 if (elements.length > 0) {
                     var trait_key = css[i][1];
                     var trait_value = css[i][2];
                     elements.css(trait_key ,trait_value);
                 }
             }
         },
 
         update_classes: function (old_classes, new_classes, $el) {
             // Update the DOM classes applied to an element, default to this.$el.
             if ($el===undefined) {
                 $el = this.$el;
             }
             this.do_diff(old_classes, new_classes, function(removed) {
                 $el.removeClass(removed);
             }, function(added) {
                 $el.addClass(added);
             });
         },
 
         update_mapped_classes: function(class_map, trait_name, previous_trait_value, $el) {
             // Update the DOM classes applied to the widget based on a single
             // trait's value.
             //
             // Given a trait value classes map, this function automatically
             // handles applying the appropriate classes to the widget element
             // and removing classes that are no longer valid.
             //
             // Parameters
             // ----------
             // class_map: dictionary
             //  Dictionary of trait values to class lists.
             //  Example:
             //      {
             //          success: ['alert', 'alert-success'],
             //          info: ['alert', 'alert-info'],
             //          warning: ['alert', 'alert-warning'],
             //          danger: ['alert', 'alert-danger']
             //      };
             // trait_name: string
             //  Name of the trait to check the value of.
             // previous_trait_value: optional string, default ''
             //  Last trait value
             // $el: optional jQuery element handle, defaults to this.$el
             //  Element that the classes are applied to.
             var key = previous_trait_value;
             if (key === undefined) {
                 key = this.model.previous(trait_name);
             }
             var old_classes = class_map[key] ? class_map[key] : [];
             key = this.model.get(trait_name);
             var new_classes = class_map[key] ? class_map[key] : [];
 
             this.update_classes(old_classes, new_classes, $el || this.$el);
         },
         
         _get_selector_element: function (selector) {
             // Get the elements via the css selector.
             var elements;
             if (!selector) {
                 elements = this.$el;
             } else {
                 elements = this.$el.find(selector).addBack(selector);
             }
             return elements;
         },
     });
 
 
     var ViewList = function(create_view, remove_view, context) {
         // * create_view and remove_view are default functions called when adding or removing views
         // * create_view takes a model and returns a view or a promise for a view for that model
         // * remove_view takes a view and destroys it (including calling `view.remove()`)
         // * each time the update() function is called with a new list, the create and remove
         //   callbacks will be called in an order so that if you append the views created in the
         //   create callback and remove the views in the remove callback, you will duplicate 
         //   the order of the list.
         // * the remove callback defaults to just removing the view (e.g., pass in null for the second parameter)
         // * the context defaults to the created ViewList.  If you pass another context, the create and remove
         //   will be called in that context.
 
         this.initialize.apply(this, arguments);
-    }
+    };
 
     _.extend(ViewList.prototype, {
         initialize: function(create_view, remove_view, context) {
             this.state_change = Promise.resolve();
             this._handler_context = context || this;
             this._models = [];
             this.views = [];
             this._create_view = create_view;
             this._remove_view = remove_view || function(view) {view.remove();};
         },
 
         update: function(new_models, create_view, remove_view, context) {
             // the create_view, remove_view, and context arguments override the defaults
             // specified when the list is created.
             // returns a promise that resolves after this update is done
             var remove = remove_view || this._remove_view;
             var create = create_view || this._create_view;
             var context = context || this._handler_context;
             var added_views = [];
             var that = this;
             this.state_change = this.state_change.then(function() {
                 var i;
                  // first, skip past the beginning of the lists if they are identical
                 for (i = 0; i < new_models.length; i++) {
                     if (i >= that._models.length || new_models[i] !== that._models[i]) {
                         break;
                     }
                 }
                 var first_removed = i;
                 // Remove the non-matching items from the old list.
                 for (var j = first_removed; j < that._models.length; j++) {
                     remove.call(context, that.views[j]);
                 }
 
                 // Add the rest of the new list items.
                 for (; i < new_models.length; i++) {
                     added_views.push(create.call(context, new_models[i]));
                 }
                 // make a copy of the input array
                 that._models = new_models.slice();
                 return Promise.all(added_views, function(added) {
                     that.views = that.views.slice(0,first_removed).concat(added);
                 });
             });
             return this.state_change;
         },
 
         remove: function() {
             // removes every view in the list; convenience function for `.update([])`
             // that should be faster
             // returns a promise that resolves after this removal is done
             var that = this;
             this.state_change = this.state_change.then(function() {
                 for (var i = 0, len=that.views.length; i <len; i++) {
                     that._remove_view.call(that._handler_context, that.views[i]);
-                };
+                }
                 that._models = [];
                 that.views = [];
             });
             return this.state_change;
         },
     });
 
     var widget = {
         'WidgetModel': WidgetModel,
         'WidgetView': WidgetView,
         'DOMWidgetView': DOMWidgetView,
         'ViewList': ViewList,
     };
 
     // For backwards compatability.
     $.extend(IPython, widget);
 
     return widget;
 });

IPython/html/static/widgets/js/widget_selectioncontainer.js

@@ -1,263 +1,264
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     "widgets/js/widget",
     "base/js/utils",
     "jquery",
     "bootstrap",
 ], function(widget, utils, $){
 
     var AccordionView = widget.DOMWidgetView.extend({
+        initialize: function(){
+            AccordionView.__super__.initialize.apply(this, arguments);
+
+            this.containers = [];
+            this.model_containers = {};
+            this.children_views = new widget.ViewList(this.add_child_model, this.remove_child_model, this);
+            this.listenTo(this.model, 'change:children', function(model, value) {
+                this.children_views.update(value);
+            }, this);
+        },
+
         render: function(){
             // Called when view is rendered.
             var guid = 'panel-group' + utils.uuid();
             this.$el
                 .attr('id', guid)
                 .addClass('panel-group');
-            this.containers = [];
-            this.model_containers = {};
-            this.update_children([], this.model.get('children'));
-            this.model.on('change:children', function(model, value, options) {
-                this.update_children(model.previous('children'), value);
-            }, this);
             this.model.on('change:selected_index', function(model, value, options) {
                 this.update_selected_index(model.previous('selected_index'), value, options);
             }, this);
             this.model.on('change:_titles', function(model, value, options) {
                 this.update_titles(value);
             }, this);
             var that = this;
             this.on('displayed', function() {
                 this.update_titles();
             }, this);
+            this.children_views.update(this.model.get('children'));
         },
 
         update_titles: function(titles) {
             // Set tab titles
             if (!titles) {
                 titles = this.model.get('_titles');
             }
 
             var that = this;
             _.each(titles, function(title, page_index) {
                 var accordian = that.containers[page_index];
                 if (accordian !== undefined) {
                     accordian
                         .find('.panel-heading')
                         .find('.accordion-toggle')
                         .text(title);
                 }
             });
         },
 
         update_selected_index: function(old_index, new_index, options) {
             // Only update the selection if the selection wasn't triggered
             // by the front-end.  It must be triggered by the back-end.
             if (options === undefined || options.updated_view != this) {
                 this.containers[old_index].find('.panel-collapse').collapse('hide');
                 if (0 <= new_index && new_index < this.containers.length) {
                     this.containers[new_index].find('.panel-collapse').collapse('show');
                 }
             }
         },
         
-        update_children: function(old_list, new_list) {
-            // Called when the children list is modified.
-            this.do_diff(old_list, 
-                new_list, 
-                $.proxy(this.remove_child_model, this),
-                $.proxy(this.add_child_model, this));
-        },
-
         remove_child_model: function(model) {
             // Called when a child is removed from children list.
             var accordion_group = this.model_containers[model.id];
             this.containers.splice(accordion_group.container_index, 1);
             delete this.model_containers[model.id];
             accordion_group.remove();
             this.pop_child_view(model);
         },
 
         add_child_model: function(model) {
             // Called when a child is added to children list.
             var index = this.containers.length;
             var uuid = utils.uuid();
             var accordion_group = $('<div />')
                 .addClass('panel panel-default')
                 .appendTo(this.$el);
             var accordion_heading = $('<div />')
                 .addClass('panel-heading')
                 .appendTo(accordion_group);
             var that = this;
             var accordion_toggle = $('<a />')
                 .addClass('accordion-toggle')
                 .attr('data-toggle', 'collapse')
                 .attr('data-parent', '#' + this.$el.attr('id'))
                 .attr('href', '#' + uuid)
                 .click(function(evt){ 
             
                     // Calling model.set will trigger all of the other views of the 
                     // model to update.
                     that.model.set("selected_index", index, {updated_view: that});
                     that.touch();
                  })
                 .text('Page ' + index)
                 .appendTo(accordion_heading);
             var accordion_body = $('<div />', {id: uuid})
                 .addClass('panel-collapse collapse')
                 .appendTo(accordion_group);
             var accordion_inner = $('<div />')
                 .addClass('panel-body')
                 .appendTo(accordion_body);
             var container_index = this.containers.push(accordion_group) - 1;
             accordion_group.container_index = container_index;
             this.model_containers[model.id] = accordion_group;
             
             var dummy = $('<div/>');
             accordion_inner.append(dummy);
             return this.create_child_view(model).then(function(view) {
                 dummy.replaceWith(view.$el);
                 that.update();
                 that.update_titles();
 
                 // Trigger the displayed event of the child view.
                 that.after_displayed(function() {
                     view.trigger('displayed');
                 });
                 return view;
             }, utils.reject("Couldn't add child view to box", true));
         },
+        
+        remove: function() {
+            AccordionView.__super__.remove.apply(this, arguments);
+            this.children_views.remove();
+        },
     });
     
 
     var TabView = widget.DOMWidgetView.extend({    
         initialize: function() {
             // Public constructor.
-            this.containers = [];
             TabView.__super__.initialize.apply(this, arguments);
+            
+            this.containers = [];
+            this.children_views = new widget.ViewList(this.add_child_model, this.remove_child_model, this);
+            this.listenTo(this.model, 'change:children', function(model, value) {
+                this.children_views.update(value);
+            }, this);
         },
 
         render: function(){
             // Called when view is rendered.
             var uuid = 'tabs'+utils.uuid();
             var that = this;
             this.$tabs = $('<div />', {id: uuid})
                 .addClass('nav')
                 .addClass('nav-tabs')
                 .appendTo(this.$el);
             this.$tab_contents = $('<div />', {id: uuid + 'Content'})
                 .addClass('tab-content')
                 .appendTo(this.$el);
-            this.containers = [];
-            this.update_children([], this.model.get('children'));
-            this.model.on('change:children', function(model, value, options) {
-                this.update_children(model.previous('children'), value);
-            }, this);
+            this.children_views.update(this.model.get('children'));
         },
 
         update_attr: function(name, value) {
             // Set a css attr of the widget view.
             this.$tabs.css(name, value);
         },
 
-        update_children: function(old_list, new_list) {
-            // Called when the children list is modified.
-            this.do_diff(old_list, 
-                new_list, 
-                $.proxy(this.remove_child_model, this),
-                $.proxy(this.add_child_model, this));
-        },
-
         remove_child_model: function(model) {
             // Called when a child is removed from children list.
             var view = this.pop_child_view(model);
             this.containers.splice(view.parent_tab.tab_text_index, 1);
             view.parent_tab.remove();
             view.parent_container.remove();
             view.remove();
         },
 
         add_child_model: function(model) {
             // Called when a child is added to children list.
             var index = this.containers.length;
             var uuid = utils.uuid();
 
             var that = this;
             var tab = $('<li />')
                 .css('list-style-type', 'none')
                 .appendTo(this.$tabs);
             
 
             var tab_text = $('<a />')
                 .attr('href', '#' + uuid)
                 .attr('data-toggle', 'tab') 
                 .text('Page ' + index)
                 .appendTo(tab)
                 .click(function (e) {
             
                     // Calling model.set will trigger all of the other views of the 
                     // model to update.
                     that.model.set("selected_index", index, {updated_view: that});
                     that.touch();
                     that.select_page(index);
                 });
             tab.tab_text_index = that.containers.push(tab_text) - 1;
 
             var dummy = $('<div />');
             var contents_div = $('<div />', {id: uuid})
                 .addClass('tab-pane')
                 .addClass('fade')
                 .append(dummy)
                 .appendTo(that.$tab_contents);
 
             return this.create_child_view(model).then(function(view) {
                 dummy.replaceWith(view.$el);
                 view.parent_tab = tab;
                 view.parent_container = contents_div;
 
                 // Trigger the displayed event of the child view.
                 that.after_displayed(function() {
                     view.trigger('displayed');
                 });
                 return view;
             }, utils.reject("Couldn't add child view to box", true));
         },
 
         update: function(options) {
             // Update the contents of this view
             //
             // Called when the model is changed.  The model may have been 
             // changed by another view or by a state update from the back-end.
             if (options === undefined || options.updated_view != this) {
                 // Set tab titles
                 var titles = this.model.get('_titles');
                 var that = this;
                 _.each(titles, function(title, page_index) {
                    var tab_text = that.containers[page_index];
                     if (tab_text !== undefined) {
                         tab_text.text(title);
                     } 
                 });
 
                 var selected_index = this.model.get('selected_index');
                 if (0 <= selected_index && selected_index < this.containers.length) {
                     this.select_page(selected_index);
                 }
             }
             return TabView.__super__.update.apply(this);
         },
 
         select_page: function(index) {
             // Select a page.
             this.$tabs.find('li')
                 .removeClass('active');
             this.containers[index].tab('show');
         },
+        
+        remove: function() {
+            TabView.__super__.remove.apply(this, arguments);
+            this.children_views.remove();
+        },
     });
 
     return {
         'AccordionView': AccordionView,
         'TabView': TabView,
     };
 });