Object
O.ViewEventsController
Most DOM events are handled via delegation. When an event occurs, it is passed to the O.ViewEventsController. This maintains a list of event targets that should receive the event before the view handles it, and a list of targets that should receive it after it has traversed the view hierarchy.
When an event is dispatched, it passes through all targets in the first
list, then is dispatched at the view which owns the node on which the event
occurred (and will bubble up the view tree from there), then passes through
all the targets that are queued to handle it after the view. Any event
handler may call event.stopPropagation(), which will stop the view from
passing to any further targets.
Standard event target priorities used in library:
| 40 | MouseEventRemover |
|---|---|
| 30 | GestureManager |
| 20 | DragController |
| 10 | ModalViewHandler -10 - GlobalKeyboardShortcuts |
"use strict";
( function ( NS ) {
var etSearch = function ( candidate, b ) {
var a = candidate[0];
return a < b ? -1 : a > b ? 1 : 0;
};
var ViewEventsController = {Private Property
O.ViewEventsController._activeViews
- Object
- private
Maps from id to the view object for all views currently in a document.
_activeViews: {},Method
O.ViewEventsController.registerActiveView( view )
Automatically called when a view is inserted into a document. Adds an internal id -> O.View mapping.
Parameters
| view | O.View The view object that has entered the document. |
|---|
Returns
O.ViewEventsController Returns self.
registerActiveView: function ( view ) {
this._activeViews[ view.get( 'id' ) ] = view;
return this;
},Method
O.ViewEventsController.deregisterActiveView( view )
Automatically called when a view is removed from a document. Removes an internal id -> O.View mapping.
Parameters
| view | O.View The view object that has left the document. |
|---|
Returns
O.ViewEventsController Returns self.
deregisterActiveView: function ( view ) {
delete this._activeViews[ view.get( 'id' ) ];
return this;
},Method
O.ViewEventsController.getViewFromNode( node )
Returns the view object that the given DOM node is a part of.
Parameters
| node | Element a DOM node. |
|---|
Returns
O.View|null The view which owns the node.
getViewFromNode: function ( node ) {
var activeViews = this._activeViews,
doc = node.ownerDocument,
view = null;
while ( !view && node && node !== doc ) {
view = activeViews[ node.id ];
node = node.parentNode;
}
return view;
},Private Property
O.ViewEventsController._eventTargets
- [Number,O.EventTarget][]
- private
List of event targets to dispatch events to.
_eventTargets: [],Method
O.ViewEventsController.addEventTarget( eventTarget, priority )
Adds an event target to queue to receive view events. The position in the queue is determined by the priority argument:
- Greater than 0 => before the view hierarchy receives the event.
- Less than 0 => after the view hierarchy receives the event.
If an existing target in the queue has the same priority as the new one, the new one will be inserted such that it fires before the old one.
Parameters
| eventTarget | O.EventTarget The event target to add. |
|---|---|
| priority | Number The priority of the event target. |
Returns
O.ViewEventsController Returns self.
addEventTarget: function ( eventTarget, priority ) {
if ( !priority ) { priority = 0; }
var eventTargets = this._eventTargets,
index = eventTargets.binarySearch( priority, etSearch ),
length = eventTargets.length;
while ( index < length && eventTargets[ index ][0] === priority ) {
index += 1;
}
eventTargets.splice( index, 0, [ priority, eventTarget ] );
return this;
},Method
O.ViewEventsController.removeEventTarget( eventTarget )
Removes an event target from the queue that was previously added via O.ViewEventsController.addEventTarget.
Parameters
| eventTarget | O.EventTarget The event target to remove from the queue. |
|---|
Returns
O.ViewEventsController Returns self.
removeEventTarget: function ( eventTarget ) {
var eventTargets = this._eventTargets,
l = eventTargets.length;
while ( l-- ) {
if ( eventTargets[l][1] === eventTarget ) {
eventTargets.splice( l, 1 );
}
}
return this;
},Method
O.ViewEventsController.handleEvent( event, view )
Dispatches an event to each of the targets registered with the
controller, until it reaches the end of the list or one of them calls
event.stopPropagation().
Parameters
| event | Event The event object to dispatch. |
|---|---|
| view | O.View Optional The view at which the event originated. This is the view the event will be fired upon after it has been through all the pushed targets. If not supplied, the view will be looked up via the DOM node in the `event.target` property. |
handleEvent: function ( event, view, _rootView ) {
var eventTargets = this._eventTargets,
l = eventTargets.length,
eventTarget;
if ( !view ) {
view = this.getViewFromNode( event.target ) || _rootView;
}
event.targetView = view;
while ( l-- ) {
eventTarget = eventTargets[l][1];
if ( eventTarget === this ) {
eventTarget = view;
}
if ( eventTarget && eventTarget.fire( event.type, event ) ) {
break;
}
}
}.invokeInRunLoop()
};
ViewEventsController.addEventTarget( ViewEventsController, 0 );
NS.ViewEventsController = ViewEventsController;
}( O ) );