Contents

NSTreeController

A bindings-compatible controller that manages a tree of objects.

Declaration

class NSTreeController

Overview

The NSTreeController class provides selection and sort management. Its primary purpose is to act as the controller when binding NSOutlineView and NSBrowser instances to a hierarchical collection of objects. The root content object of the tree can be a single object, or an array of objects.

An NSTreeController object requires that you describe how the tree of objects is traversed by specifying the key-path for child objects specified by childrenKeyPath. All child objects for the tree must be key-value coding compliant for the same child key path. If necessary, you should add properties to your model classes that map the child key name to the appropriate class-specific property name.

Child objects can implement a count method (specified to the tree controller using countKeyPath) that, if provided, returns the number of child objects available. Your model objects are expected to update the value of the count key path in a key-value observing compliant method. Optionally, you can also provide a leaf key path using leafKeyPath that specifies a key in your model object that returns true if the object is a leaf node, and false if it is not. Changes to the leaf node value of the child object should be made in a key-value observing compliant manner. Providing the leaf node key path can improve performance, because it prevents the NSTreeController from having to examine the child object to determine if it is a leaf node.

For more information about using NSTreeController in your app, see Navigating Hierarchical Data Using Outline and Split Views.

Topics

Managing Sort Descriptors

Setting the content

Arranging Objects

Getting the current selection

Managing Selections

Adding, inserting and removing objects

Specifying model attributes

See Also

Tree-Based Data