Class Ember.View
Ember.View
is the class in Ember responsible for encapsulating templates of
HTML content, combining templates with data to render as sections of a page's
DOM, and registering and responding to user-initiated events.
HTML Tag
The default HTML tag name used for a view's DOM representation is div
. This
can be customized by setting the tagName
property. The following view
class:
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ParagraphView = Ember.View.extend({
tagName: 'em'
}); |
Would result in instances with the following HTML:
1 |
<em id="ember1" class="ember-view"></em> |
HTML class
Attribute
The HTML class
attribute of a view's tag can be set by providing a
classNames
property that is set to an array of strings:
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MyView = Ember.View.extend({ classNames: ['my-class', 'my-other-class'] }); |
Will result in view instances with an HTML representation of:
1 |
<div id="ember1" class="ember-view my-class my-other-class"></div> |
class
attribute values can also be set by providing a classNameBindings
property set to an array of properties names for the view. The return value
of these properties will be added as part of the value for the view's class
attribute. These properties can be computed properties:
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MyView = Ember.View.extend({ classNameBindings: ['propertyA', 'propertyB'], propertyA: 'from-a', propertyB: function() { if (someLogic) { return 'from-b'; } }.property() }); |
Will result in view instances with an HTML representation of:
1 |
<div id="ember1" class="ember-view from-a from-b"></div> |
If the value of a class name binding returns a boolean the property name
itself will be used as the class name if the property is true. The class name
will not be added if the value is false
or undefined
.
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MyView = Ember.View.extend({ classNameBindings: ['hovered'], hovered: true }); |
Will result in view instances with an HTML representation of:
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<div id="ember1" class="ember-view hovered"></div> |
When using boolean class name bindings you can supply a string value other
than the property name for use as the class
HTML attribute by appending the
preferred value after a ":" character when defining the binding:
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MyView = Ember.View.extend({ classNameBindings: ['awesome:so-very-cool'], awesome: true }); |
Will result in view instances with an HTML representation of:
1 |
<div id="ember1" class="ember-view so-very-cool"></div> |
Boolean value class name bindings whose property names are in a camelCase-style format will be converted to a dasherized format:
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MyView = Ember.View.extend({ classNameBindings: ['isUrgent'], isUrgent: true }); |
Will result in view instances with an HTML representation of:
1 |
<div id="ember1" class="ember-view is-urgent"></div> |
Class name bindings can also refer to object values that are found by traversing a path relative to the view itself:
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MyView = Ember.View.extend({ classNameBindings: ['messages.empty'] messages: Ember.Object.create({ empty: true }) }); |
Will result in view instances with an HTML representation of:
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<div id="ember1" class="ember-view empty"></div> |
If you want to add a class name for a property which evaluates to true and and a different class name if it evaluates to false, you can pass a binding like this:
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// Applies 'enabled' class when isEnabled is true and 'disabled' when isEnabled is false Ember.View.extend({ classNameBindings: ['isEnabled:enabled:disabled'] isEnabled: true }); |
Will result in view instances with an HTML representation of:
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<div id="ember1" class="ember-view enabled"></div> |
When isEnabled is false
, the resulting HTML reprensentation looks like
this:
1 |
<div id="ember1" class="ember-view disabled"></div> |
This syntax offers the convenience to add a class if a property is false
:
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// Applies no class when isEnabled is true and class 'disabled' when isEnabled is false Ember.View.extend({ classNameBindings: ['isEnabled::disabled'] isEnabled: true }); |
Will result in view instances with an HTML representation of:
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<div id="ember1" class="ember-view"></div> |
When the isEnabled
property on the view is set to false
, it will result
in view instances with an HTML representation of:
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<div id="ember1" class="ember-view disabled"></div> |
Updates to the the value of a class name binding will result in automatic
update of the HTML class
attribute in the view's rendered HTML
representation. If the value becomes false
or undefined
the class name
will be removed.
Both classNames
and classNameBindings
are concatenated properties. See
Ember.Object documentation for more
information about concatenated properties.
HTML Attributes
The HTML attribute section of a view's tag can be set by providing an
attributeBindings
property set to an array of property names on the view.
The return value of these properties will be used as the value of the view's
HTML associated attribute:
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AnchorView = Ember.View.extend({ tagName: 'a', attributeBindings: ['href'], href: 'http://google.com' }); |
Will result in view instances with an HTML representation of:
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<a id="ember1" class="ember-view" href="http://google.com"></a> |
If the return value of an attributeBindings
monitored property is a boolean
the property will follow HTML's pattern of repeating the attribute's name as
its value:
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MyTextInput = Ember.View.extend({ tagName: 'input', attributeBindings: ['disabled'], disabled: true }); |
Will result in view instances with an HTML representation of:
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<input id="ember1" class="ember-view" disabled="disabled" /> |
attributeBindings
can refer to computed properties:
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MyTextInput = Ember.View.extend({ tagName: 'input', attributeBindings: ['disabled'], disabled: function() { if (someLogic) { return true; } else { return false; } }.property() }); |
Updates to the the property of an attribute binding will result in automatic update of the HTML attribute in the view's rendered HTML representation.
attributeBindings
is a concatenated property. See Ember.Object
documentation for more information about concatenated properties.
Templates
The HTML contents of a view's rendered representation are determined by its
template. Templates can be any function that accepts an optional context
parameter and returns a string of HTML that will be inserted within the
view's tag. Most typically in Ember this function will be a compiled
Ember.Handlebars
template.
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AView = Ember.View.extend({ template: Ember.Handlebars.compile('I am the template') }); |
Will result in view instances with an HTML representation of:
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<div id="ember1" class="ember-view">I am the template</div> |
Within an Ember application is more common to define a Handlebars templates as part of a page:
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<script type='text/x-handlebars' data-template-name='some-template'> Hello </script> |
And associate it by name using a view's templateName
property:
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AView = Ember.View.extend({
templateName: 'some-template'
}); |
Using a value for templateName
that does not have a Handlebars template
with a matching data-template-name
attribute will throw an error.
For views classes that may have a template later defined (e.g. as the block
portion of a {{view}}
Handlebars helper call in another template or in
a subclass), you can provide a defaultTemplate
property set to compiled
template function. If a template is not later provided for the view instance
the defaultTemplate
value will be used:
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AView = Ember.View.extend({ defaultTemplate: Ember.Handlebars.compile('I was the default'), template: null, templateName: null }); |
Will result in instances with an HTML representation of:
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<div id="ember1" class="ember-view">I was the default</div> |
If a template
or templateName
is provided it will take precedence over
defaultTemplate
:
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AView = Ember.View.extend({ defaultTemplate: Ember.Handlebars.compile('I was the default') }); aView = AView.create({ template: Ember.Handlebars.compile('I was the template, not default') }); |
Will result in the following HTML representation when rendered:
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<div id="ember1" class="ember-view">I was the template, not default</div> |
View Context
The default context of the compiled template is the view's controller:
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AView = Ember.View.extend({ template: Ember.Handlebars.compile('Hello {{excitedGreeting}}') }); aController = Ember.Object.create({ firstName: 'Barry', excitedGreeting: function() { return this.get("content.firstName") + "!!!" }.property() }); aView = AView.create({ controller: aController, }); |
Will result in an HTML representation of:
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<div id="ember1" class="ember-view">Hello Barry!!!</div> |
A context can also be explicitly supplied through the view's context
property. If the view has neither context
nor controller
properties, the
parentView
's context will be used.
Layouts
Views can have a secondary template that wraps their main template. Like
primary templates, layouts can be any function that accepts an optional
context parameter and returns a string of HTML that will be inserted inside
view's tag. Views whose HTML element is self closing (e.g. <input />
)
cannot have a layout and this property will be ignored.
Most typically in Ember a layout will be a compiled Ember.Handlebars
template.
A view's layout can be set directly with the layout
property or reference
an existing Handlebars template by name with the layoutName
property.
A template used as a layout must contain a single use of the Handlebars
{{yield}}
helper. The HTML contents of a view's rendered template
will be
inserted at this location:
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AViewWithLayout = Ember.View.extend({ layout: Ember.Handlebars.compile("<div class='my-decorative-class'>{{yield}}</div>") template: Ember.Handlebars.compile("I got wrapped"), }); |
Will result in view instances with an HTML representation of:
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<div id="ember1" class="ember-view"> <div class="my-decorative-class"> I got wrapped </div> </div> |
See Ember.Handlebars.helpers.yield for more information.
Responding to Browser Events
Views can respond to user-initiated events in one of three ways: method
implementation, through an event manager, and through {{action}}
helper use
in their template or layout.
Method Implementation
Views can respond to user-initiated events by implementing a method that
matches the event name. A jQuery.Event
object will be passed as the
argument to this method.
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AView = Ember.View.extend({ click: function(event) { // will be called when when an instance's // rendered element is clicked } }); |
Event Managers
Views can define an object as their eventManager
property. This object can
then implement methods that match the desired event names. Matching events
that occur on the view's rendered HTML or the rendered HTML of any of its DOM
descendants will trigger this method. A jQuery.Event
object will be passed
as the first argument to the method and an Ember.View
object as the
second. The Ember.View
will be the view whose rendered HTML was interacted
with. This may be the view with the eventManager
property or one of its
descendent views.
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AView = Ember.View.extend({ eventManager: Ember.Object.create({ doubleClick: function(event, view) { // will be called when when an instance's // rendered element or any rendering // of this views's descendent // elements is clicked } }) }); |
An event defined for an event manager takes precedence over events of the same name handled through methods on the view.
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AView = Ember.View.extend({ mouseEnter: function(event) { // will never trigger. }, eventManager: Ember.Object.create({ mouseEnter: function(event, view) { // takes precedence over AView#mouseEnter } }) }); |
Similarly a view's event manager will take precedence for events of any views
rendered as a descendent. A method name that matches an event name will not
be called if the view instance was rendered inside the HTML representation of
a view that has an eventManager
property defined that handles events of the
name. Events not handled by the event manager will still trigger method calls
on the descendent.
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OuterView = Ember.View.extend({ template: Ember.Handlebars.compile("outer {{#view InnerView}}inner{{/view}} outer"), eventManager: Ember.Object.create({ mouseEnter: function(event, view) { // view might be instance of either // OuterView or InnerView depending on // where on the page the user interaction occured } }) }); InnerView = Ember.View.extend({ click: function(event) { // will be called if rendered inside // an OuterView because OuterView's // eventManager doesn't handle click events }, mouseEnter: function(event) { // will never be called if rendered inside // an OuterView. } }); |
Handlebars {{action}}
Helper
See Handlebars.helpers.action.
Event Names
All of the event handling approaches described above respond to the same set
of events. The names of the built-in events are listed below. (The hash of
built-in events exists in Ember.EventDispatcher
.) Additional, custom events
can be registered by using Ember.Application.customEvents
.
Touch events:
touchStart
touchMove
touchEnd
touchCancel
Keyboard events
keyDown
keyUp
keyPress
Mouse events
mouseDown
mouseUp
contextMenu
click
doubleClick
mouseMove
focusIn
focusOut
mouseEnter
mouseLeave
Form events:
submit
change
focusIn
focusOut
input
HTML5 drag and drop events:
dragStart
drag
dragEnter
dragLeave
drop
dragEnd
Handlebars {{view}}
Helper
Other Ember.View
instances can be included as part of a view's template by
using the {{view}}
Handlebars helper. See Ember.Handlebars.helpers.view
for additional information.
Methods
- $
- addObserver
- append
- appendTo
- beginPropertyChanges
- cacheFor
- create
- createChildView
- createElement
- createWithMixins
- decrementProperty
- destroy
- destroyElement
- eachComputedProperty
- endPropertyChanges
- findElementInParentElement
- get
- getProperties
- getWithDefault
- has
- hasObserverFor
- incrementProperty
- init
- metaForProperty
- notifyPropertyChange
- off
- on
- one
- propertyDidChange
- propertyWillChange
- remove
- removeAllChildren
- removeChild
- removeFromParent
- removeObserver
- render
- reopen
- reopenClass
- replaceIn
- rerender
- set
- setProperties
- toString
- toggleProperty
- trigger
- willDestroy
Properties
- ariaRole
- attributeBindings
- classNameBindings
- classNames
- concatenatedProperties
- context
- controller
- element
- isDestroyed
- isDestroying
- isView
- isVisible
- layout
- layoutName
- nearestChildOf
- nearestOfType
- nearestWithProperty
- parentView
- tagName
- template
- templateName
- templates
- views