3 Copyright 2012 Yahoo! Inc. All rights reserved.
4 Licensed under the BSD License.
5 http://yuilibrary.com/license/
7 YUI.add('view', function (Y, NAME) {
10 Represents a logical piece of an application's user interface, and provides a
11 lightweight, overridable API for rendering content and handling delegated DOM
12 events on a container element.
20 Represents a logical piece of an application's user interface, and provides a
21 lightweight, overridable API for rendering content and handling delegated DOM
22 events on a container element.
24 The View class imposes little structure and provides only minimal functionality
25 of its own: it's basically just an overridable API interface that helps you
26 implement custom views.
28 As of YUI 3.5.0, View allows ad-hoc attributes to be specified at instantiation
29 time, so you don't need to subclass `Y.View` to add custom attributes. Just pass
30 them to the constructor:
32 var view = new Y.View({foo: 'bar'});
33 view.get('foo'); // => "bar"
42 View.superclass.constructor.apply(this, arguments);
45 Y.View = Y.extend(View, Y.Base, {
46 // -- Public Properties ----------------------------------------------------
49 Template for this view's container.
51 @property containerTemplate
56 containerTemplate: '<div/>',
59 Hash of CSS selectors mapped to events to delegate to elements matching
62 CSS selectors are relative to the `container` element. Events are attached
63 to the container, and delegation is used so that subscribers are only
64 notified of events that occur on elements inside the container that match
65 the specified selectors. This allows the container's contents to be re-
66 rendered as needed without losing event subscriptions.
68 Event handlers can be specified either as functions or as strings that map
69 to function names on this view instance or its prototype.
71 The `this` object in event handlers will refer to this view instance. If
72 you'd prefer `this` to be something else, use `Y.bind()` to bind a custom
77 var view = new Y.View({
79 // Call `this.toggle()` whenever the element with the id
80 // "toggle-button" is clicked.
81 '#toggle-button': {click: 'toggle'},
83 // Call `this.hoverOn()` when the mouse moves over any element
84 // with the "hoverable" class, and `this.hoverOff()` when the
85 // mouse moves out of any element with the "hoverable" class.
100 Template for this view's contents.
102 This is a convenience property that has no default behavior of its own.
103 It's only provided as a convention to allow you to store whatever you
104 consider to be a template, whether that's an HTML string, a `Y.Node`
105 instance, a Mustache template, or anything else your little heart
108 How this template gets used is entirely up to you and your custom
117 // -- Protected Properties -------------------------------------------------
120 This tells `Y.Base` that it should create ad-hoc attributes for config
121 properties passed to View's constructor. This makes it possible to
122 instantiate a view and set a bunch of attributes without having to subclass
123 `Y.View` and declare all those attributes first.
125 @property _allowAdHocAttrs
131 _allowAdHocAttrs: true,
133 // -- Lifecycle Methods ----------------------------------------------------
134 initializer: function (config) {
135 config || (config = {});
137 // Set instance properties specified in the config.
138 config.containerTemplate &&
139 (this.containerTemplate = config.containerTemplate);
141 config.template && (this.template = config.template);
143 // Merge events from the config into events in `this.events`.
144 this.events = config.events ? Y.merge(this.events, config.events) :
147 // When the container node changes (or when it's set for the first
148 // time), we'll attach events to it, but not until then. This allows the
149 // container to be created lazily the first time it's accessed rather
150 // than always on init.
151 this.after('containerChange', this._afterContainerChange);
155 Destroys this View, detaching any DOM events and optionally also destroying
158 By default, the container node will not be destroyed. Pass an _options_
159 object with a truthy `remove` property to destroy the container as well.
162 @param {Object} [options] Options.
163 @param {Boolean} [options.remove=false] If `true`, this View's container
164 will be removed from the DOM and destroyed as well.
167 destroy: function (options) {
168 // We also accept `delete` as a synonym for `remove`.
169 if (options && (options.remove || options['delete'])) {
170 // Attaching an event handler here because the `destroy` event is
171 // preventable. If we destroyed the container before calling the
172 // superclass's `destroy()` method and the event was prevented, the
173 // class would end up in a broken state.
174 this.onceAfter('destroy', function () {
175 this._destroyContainer();
179 return View.superclass.destroy.call(this);
182 destructor: function () {
184 delete this._container;
187 // -- Public Methods -------------------------------------------------------
190 Attaches delegated event handlers to this view's container element. This
191 method is called internally to subscribe to events configured in the
192 `events` attribute when the view is initialized.
194 You may override this method to customize the event attaching logic.
197 @param {Object} [events] Hash of events to attach. See the docs for the
198 `events` attribute for details on the format. If not specified, this
199 view's `events` property will be used.
203 attachEvents: function (events) {
204 var container = this.get('container'),
205 owns = Y.Object.owns,
206 handler, handlers, name, selector;
210 events || (events = this.events);
212 for (selector in events) {
213 if (!owns(events, selector)) { continue; }
215 handlers = events[selector];
217 for (name in handlers) {
218 if (!owns(handlers, name)) { continue; }
220 handler = handlers[name];
222 // TODO: Make this more robust by using lazy-binding:
223 // `handler = Y.bind(handler, this);`
224 if (typeof handler === 'string') {
225 handler = this[handler];
232 this._attachedViewEvents.push(
233 container.delegate(name, handler, selector, this));
241 Creates and returns a container node for this view.
243 By default, the container is created from the HTML template specified in the
244 `containerTemplate` property, and is _not_ added to the DOM automatically.
246 You may override this method to customize how the container node is created
247 (such as by rendering it from a custom template format). Your method must
248 return a `Y.Node` instance.
251 @param {HTMLElement|Node|String} [container] Selector string, `Y.Node`
252 instance, or DOM element to use at the container node.
253 @return {Node} Node instance of the created container node.
255 create: function (container) {
256 return container ? Y.one(container) :
257 Y.Node.create(this.containerTemplate);
261 Detaches DOM events that have previously been attached to the container by
268 detachEvents: function () {
269 Y.Array.each(this._attachedViewEvents, function (handle) {
275 this._attachedViewEvents = [];
280 Removes this view's container element from the DOM (if it's in the DOM),
281 but doesn't destroy it or any event listeners attached to it.
286 remove: function () {
287 var container = this.get('container');
288 container && container.remove();
295 This method is a noop by default. Override it to provide a custom
296 implementation that renders this view's content and appends it to the
297 container element. Ideally your `render` method should also return `this` as
298 the end to allow chaining, but that's up to you.
300 Since there's no default renderer, you're free to render your view however
301 you see fit, whether that means manipulating the DOM directly, dumping
302 strings into `innerHTML`, or using a template language of some kind.
304 For basic templating needs, `Y.Node.create()` and `Y.Lang.sub()` may
305 suffice, but there are no restrictions on what tools or techniques you can
306 use to render your view. All you need to do is append something to the
307 container element at some point, and optionally append the container
308 to the DOM if it's not there already.
313 render: function () {
317 // -- Protected Methods ----------------------------------------------------
320 Removes the `container` from the DOM and purges all its event listeners.
322 @method _destroyContainer
325 _destroyContainer: function () {
326 var container = this.get('container');
327 container && container.remove(true);
331 Getter for the `container` attribute.
333 @method _getContainer
334 @param {Node|null} value Current attribute value.
335 @return {Node} Container node.
339 _getContainer: function (value) {
340 // This wackiness is necessary to enable fully lazy creation of the
341 // container node both when no container is specified and when one is
342 // specified via a valueFn.
344 if (!this._container) {
346 // Attach events to the container when it's specified via a
347 // valueFn, which won't fire the containerChange event.
348 this._container = value;
351 // Create a default container and set that as the new attribute
352 // value. The `this._container` property prevents infinite
354 value = this._container = this.create();
355 this._set('container', value);
362 // -- Protected Event Handlers ---------------------------------------------
365 Handles `containerChange` events. Detaches event handlers from the old
366 container (if any) and attaches them to the new container.
368 Right now the `container` attr is initOnly so this event should only ever
369 fire the first time the container is created, but in the future (once Y.App
370 can handle it) we may allow runtime container changes.
372 @method _afterContainerChange
376 _afterContainerChange: function () {
377 this.attachEvents(this.events);
384 Container node into which this view's content will be rendered.
386 The container node serves as the host for all DOM events attached by the
387 view. Delegation is used to handle events on children of the container,
388 allowing the container's contents to be re-rendered at any time without
389 losing event subscriptions.
391 The default container is a `<div>` Node, but you can override this in
392 a subclass, or by passing in a custom `container` config value at
393 instantiation time. If you override the default container in a subclass
394 using `ATTRS`, you must use the `valueFn` property. The view's constructor
395 will ignore any assignments using `value`.
397 When `container` is overridden by a subclass or passed as a config
398 option at instantiation time, you can provide it as a selector string, a
399 DOM element, a `Y.Node` instance, or (if you are subclassing and modifying
400 the attribute), a `valueFn` function that returns a `Y.Node` instance.
401 The value will be converted into a `Y.Node` instance if it isn't one
404 The container is not added to the page automatically. This allows you to
405 have full control over how and when your view is actually rendered to
409 @type HTMLElement|Node|String
410 @default Y.Node.create(this.containerTemplate)
414 getter : '_getContainer',
421 Properties that shouldn't be turned into ad-hoc attributes when passed to
424 @property _NON_ATTRS_CFG
439 }, '3.7.2', {"requires": ["base-build", "node-event-delegate"]});