Invoked when the user double clicks on an item (or single clicks of actOnSelect is true)

Set this to the name of the action you want to send down the responder chain when the user double clicks on an item (or single clicks if actOnSelect is true). You can optionally specify a specific target as well using the target property.

If you do not specify an action, then the collection view will also try to invoke the action named on the target item view.

Trigger the action method on a single click.

Normally, clicking on an item view in a collection will select the content object and double clicking will trigger the action method on the collection view.

If you set this property to YES, then clicking on a view will both select it (if isSelected is true) and trigger the action method.

Use this if you are using the collection view as a menu of items.

This computed property returns an index set selecting all content indexes. It will recompute anytime the length of the collection view changes.

This is used by the default contentIndexesInRect() implementation.

Allow the user to delete items using the delete key

If true the user will be allowed to delete selected items using the delete key. Otherwise deletes will not be permitted.

When canDeleteContent is true, item views will have the isDeletable property set to true (if the isEditable is true on the collection).

Allow user to edit the content by double clicking on it or hitting return. This will only work if isEditable is YES and the item view implements the beginEditing() method.

When canEditContent is true, item views will have the isEditable property set to true (if the isEditable is true on the collection).

Allow user to reorder items using drag and drop.

If true, the user can use drag and drop to reorder items in the list. If you also accept drops, this will allow the user to drop items into specific points in the list. Otherwise items will be added to the end.

When canReorderContent is true, item views will have the isReorderable property set to true (if the isEditable is true on the collection).

An array of content objects

This array should contain the content objects you want the collection view to display. An item view (based on the exampleView view class) will be created for each content object, in the order the content objects appear in this array.

If you make the collection editable, the collection view will also modify this array using the observable array methods of SC.Array.

Usually you will want to bind this property to a controller property that actually contains the array of objects you to display.

The delegate responsible for providing additional display information about the content. If you bind a collection view to a controller, this the content will usually also be the content delegate, though you could implement your own delegate if you prefer.

If set, this key will be used to get the example view for a given content object. The exampleView property will be ignored.

If set, this key will be used to get the example view for a given content object. The groupExampleView property will be ignored.

Property on content items to use for display.

Built-in item views such as the LabelViews and ImageViews will use the value of this property as a key on the content object to determine the value they should display.

For example, if you set contentValueKey to 'name' and set the exampleView to an SC.LabelView, then the label views created by the collection view will display the value of the content.name.

If you are writing your own custom item view for a collection, you can get this behavior automatically by including the SC.Control mixin on your view. You can also ignore this property if you like. The collection view itself does not use this property to impact rendering.

Delegate used to implement fine-grained control over collection view behaviors.

You can assign a delegate object to this property that will be consulted for various decisions regarding drag and drop, selection behavior, and even rendering. The object you place here must implement some or all of the SC.CollectionViewDelegate mixin.

If you do not supply a delegate but the content object you set implements the SC.CollectionViewDelegate mixin, then the content will be automatically set as the delegate. Usually you will work with a CollectionView in this way rather than setting a delegate explicitly.

This property is set to the IndexSet of content objects that are the subject of a drag whenever a drag is initiated on the collection view. You can consult this property when implementing your collection view delegate methods, but otherwise you should not use this property in your code.

Implements the drag data source protocol for the collection view. This property will consult the collection view delegate if one is provided. It will also do the right thing if you have set canReorderContent to YES.

The view class to use when creating new item views.

The collection view will automatically create an instance of the view class you set here for each item in its content array. You should provide your own subclass for this property to display the type of content you want.

The view you set here should understand the following properties, which it can use to alter its display:

• content -- The content object from the content array your view should display.
• isEnabled -- False if the view should appear disabled.
• isSelected -- True if the view should appear selected.
• contentIndex -- The current index of the view's content.
• isEditable -- True if the view should appear editable by clicking on it or hitting the Return key.
• isReorderable -- True if the view should appear reorderable by dragging it.
• isDeletable -- True if the view should appear deletable, by clicking on a delete button within it or hitting the Delete key.

Working with View and Element Pooling

As noted in the SC.CollectionView description above, by default the few instances that are needed of the exampleView class will be created and then reused. Reusing an exampleView means that the content, isSelected, isEnabled, isEditable, isReorderable, isDeletable and contentIndex properties will be updated as an existing view is pulled from the pool to be displayed.

If your custom exampleView class has trouble being reused, you may want to implement the sleepInPool and awakeFromPool methods in your exampleView. These two methods will be called on the view, one before it is pooled, sleepInPool, and the other before it is unpooled, awakeFromPool. For example, if your item views have images and there is a delay for new images to appear, you may want to use sleepInPool to ensure the previous image is unloaded so it doesn't appear momentarily while the new image loads.

Also, if the rendered output of your exampleView does not update properly you can disable reuse of the layer by setting isLayerReusable to false. This will reduce the performance of your collection though and it is recommended that you instead look at ways to properly update the existing layer as the content changes.

Finally, if you really don't want view or element reuse at all, you may disable them both by setting isReusable to false in your exampleView class. Your collection will still benefit greatly from incremental rendering, but it will perform slightly less well than with optimal re-use.

Event handling

In general you do not want your child views to actually respond to mouse and keyboard events themselves. It is better to let the collection view do that.

If you do implement your own event handlers such as mouseDown or mouseUp, you should be sure to actually call the same method on the collection view to give it the chance to perform its own selection housekeeping.

The view class to use when creating new group item views.

The collection view will automatically create an instance of the view class you set here for each item in its content array. You should provide your own subclass for this property to display the type of content you want.

If you leave this set to null then the regular example view will be used with the isGroupView property set to YES on the item view.

Changing this property value by default will cause the CollectionView to add/remove an 'active' class name to the root element.

Accept drops for data other than reordering.

Setting this property to return true when the view is instantiated will cause it to be registered as a drop target, activating the other drop machinery.

Allow user to edit content views.

Whenever isEditable is false, the user will not be able to reorder, add, or delete items regardless of the canReorderContent and canDeleteContent and isDropTarget properties.

Enable or disable the view.

The collection view will set the isEnabled property of its item views to reflect the same view of this property. Whenever isEnabled is false, the collection view will also be not selectable or editable, regardless of the settings for isEditable & isSelectable.

Allow user to select content using the mouse and keyboard.

Set this property to NO to disallow the user from selecting items. If you have items in your selectedIndexes property, they will still be reflected visually.

The set of indexes that are currently tracked by the collection view. This property is used to determine the range of items the collection view should monitor for changes.

The default implementation of this property returns an index set covering the entire range of the content. It changes automatically whenever the length changes.

Note that the returned index set for this property will always be frozen. To change the nowShowing index set, you must create a new index set and apply it.

This property is set to the proposed drop operation during a call to collectionViewValidateDragOperation(). Your delegate implementations can change the value of this property to enforce a different type of drop operation.

This property is set to the proposed insertion index during a call to collectionViewValidateDragOperation(). Your delegate implementations can change the value of this property to enforce a drop some in some other location.

When reordering its content, the collection view will store its reorder data using this special data type. The data type is unique to each collection view instance. You can use this data type to detect reorders if necessary.

Invoked when the user single clicks on the right icon of an item.

Set this to the name of the action you want to send down the responder chain when the user single clicks on the right icon of an item You can optionally specify a specific target as well using the rightIconTarget property.

Optional target to send the action to when the user clicks on the right icon of an item.

If you set the rightIconAction property to the name of an action, you can optionally specify the target object you want the action to be sent to. This can be either an actual object or a property path that will resolve to an object at the time that the action is invoked.

Indexes of selected content objects. This SC.SelectionSet is modified automatically by the collection view when the user changes the selection on the collection.

Any item views representing content objects in this set will have their isSelected property set to YES automatically.

The delegate responsible for handling selection changes. This property will be either the delegate, content, or the collection view itself, whichever implements the SC.CollectionViewDelegate mixin.

Select an item immediately on mouse down

Normally as soon as you begin a click the item will be selected.

In some UI scenarios, you might want to prevent selection until the mouse is released, so you can perform, for instance, a drag operation without actually selecting the target item.

Optional target to send the action to when the user double clicks.

If you set the action property to the name of an action, you can optionally specify the target object you want the action to be sent to. This can be either an actual object or a property path that will resolve to an object at the time that the action is invoked.

If YES, uses the experimental fast CollectionView path. Note* The performance improvements in the experimental code have been integrated directly into SC.CollectionView. If you have set this property to true, you should set it to false and refer to the class documentation explaining how to modify the performance boost behavior if necessary.

Generally, no modifications should be necessary and you should see an immediate performance improvement in all collections, especially on mobile devices.

Use toggle selection instead of normal click behavior.

If set to true, then selection will use a toggle instead of the normal click behavior. Command modifiers will be ignored and instead clicking once will select an item and clicking on it again will deselect it.