Legacy Document
Important: The information in this document is obsolete and should not be used for new development.
NSObjectController
| Inherits from | |
| Implements | |
| Package | com.apple.cocoa.application |
| Availability | Available in Mac OS X v10.3 and later. |
| Companion guides |
Overview
NSObjectController is a Cocoa bindings compatible controller class. Properties of the content object of an instance of this class can be bound to user interface elements to access and modify their values.
By default the content object of an NSObjectController instance is NSMutableDictionary. This allows a single NSObjectController instance to be used to manage many different properties referenced by key value paths. The default content object class can be changed by calling setObjectClass, which subclassers must override.
Tasks
Constructors
Managing Content
Setting the Content Class
Managing Objects
Managing Entity Names
Managing Editing
Managing Fetch Predicates
Core Data Object Contexts
Obtaining Selections
Validating Menu Items
Constructors
NSObjectController
Creates and returns an empty NSObjectController.
public NSObjectController()
Availability
- Available in Mac OS X v10.3 and later.
Creates and returns an NSObjectController with the specified content.
public NSObjectController(Object content)
Availability
- Available in Mac OS X v10.3 and later.
Instance Methods
add
Creates a new object of the class specified by objectClass and sets it as the receiver’s content object using addObject.
public void add(Object sender)
Discussion
The sender is typically the object that invoked this method.
Availability
- Available in Mac OS X v10.3 and later.
See Also
addObject
Sets object as the receiver’s content object.
public void addObject(Object object)
Discussion
If the receiver's content is bound to another object or controller through a relationship key, the relationship of the “master” object is changed.
Availability
- Available in Mac OS X v10.3 and later.
See Also
automaticallyPreparesContent
Returns true if the receiver invokes prepareContent automatically when the receiver is loaded from a nib.
public boolean automaticallyPreparesContent()
Discussion
If the receiver has a mananged object context set, it automatically fetches data from the managed object context using the current fetch predicate. The default is true..
Availability
- Available in Mac OS X v10.3 and later.
See Also
canAdd
Returns true if an object can be added to the receiver using add.
public boolean canAdd()
Discussion
Bindings can use this method to control the enabling of user interface objects.
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
canRemove
Returns true if an object can be removed from the receiver using remove.
public boolean canRemove()
Discussion
Bindings can use this method to control the enabling of user interface objects.
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
content
Returns the receiver’s content object.
public Object content()
Discussion
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
entityName
Returns the entity name used by the receiver to create new objects.
public NSString entityName()
Availability
- Available in Mac OS X v10.4 and later.
See Also
fetch
Causes the receiver to fetch the data objects specified by the entity name and fetch predicate.
public void fetch(Object sender)
Availability
- Available in Mac OS X v10.4 and later.
See Also
isEditable
Returns true if the receiver allows adding and removing objects.
public boolean isEditable()
Discussion
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
managedObjectContext
Returns the receiver’s managed object context.
public NSManagedObjectContext managedObjectContext()
Availability
- Available in Mac OS X v10.4 and later.
See Also
newObject
Creates and returns a new object of the class specified by objectClass.
public Object newObject()
Discussion
This method is called when adding and inserting objects if setAutomaticallyPreparesContent is true.
The default implementation assumes the class returned by objectClass has a standard initialization method.
Availability
- Available in Mac OS X v10.3 and later.
See Also
objectClass
Returns the class used when creating new objects.
public Class objectClass()
Discussion
The default class is NSMutableDictionary.
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
prepareContent
Typically overridden by subclasses that require additional control over the creation of new objects.
public void prepareContent()
Discussion
Subclasses that implement this method are responsible for creating the new content object and setting it as the receiver’s content object. This method is only called if setAutomaticallyPreparesContent has been set to true.
Availability
- Available in Mac OS X v10.3 and later.
See Also
remove
Removes the receiver’s content object using removeObject.
public void remove(Object sender)
Discussion
The sender is typically the object that invoked this method.
Availability
- Available in Mac OS X v10.3 and later.
See Also
removeObject
If object is the receiver’s content object, the receiver’s content is set to null.
public void removeObject(Object object)
Discussion
If the receiver's content is bound to another object or controller through a relationship key, the relationship of the ‘master’ object is cleared.
Availability
- Available in Mac OS X v10.3 and later.
See Also
selectedObjects
Returns an array of all objects to be affected by editing.
public NSArray selectedObjects()
Discussion
If the receiver supports a selection mechanism the array contains key value coding compliant proxies of the selected objects; otherwise proxies for all content objects are returned. If the receiver is a concrete instance of NSObjectController, returns an array containing the receiver’s content object.
You should avoid registering for key-value observing changes for key paths that pass through this method, that is selectedObjects.firstName. Using the proxy returned by the selection method is better for performance.
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
selection
Returns a proxy object representing the receiver’s selection.
public Object selection()
Discussion
If a value requested from the selection proxy using key-value coding returns multiple objects, the controller has no selection, or the proxy is not key-value coding compliant for the requested key, the appropriate marker (MultipleValuesMarker, NoSelectionMarker or NotApplicableMarker) is returned. Otherwise, the value of the key is returned. This proxy is fully key-value coding compliant.
This property is observable using key-value observing.
Availability
- Available in Mac OS X v10.3 and later.
See Also
setAutomaticallyPreparesContent
Sets whether the receiver creates and inserts new content objects automatically when loading from a nib file.
public void setAutomaticallyPreparesContent(boolean flag)
Discussion
If flag is true and the receiver is not using a managed object context, prepareContent is used to create the content object. If flag is true and a managed object context is set, the initial content is fetched from the managed object context using the current fetch predicate.
Setting flag to true is the same as checking the “Automatically Prepares Content” option in the Interface Builder controller inspector.
Availability
- Available in Mac OS X v10.3 and later.
See Also
setContent
Set’s the receiver’s content object to content.
public void setContent(Object content)
Availability
- Available in Mac OS X v10.3 and later.
See Also
setEditable
Sets whether the receiver allows adding and removing objects.
public void setEditable(boolean flag)
Discussion
The default is true.
Availability
- Available in Mac OS X v10.3 and later.
See Also
setEntityName
Sets the receiver’s entity name to entityName.
public void setEntityName(NSString entityName)
Availability
- Available in Mac OS X v10.4 and later.
See Also
setFetchPredicate
Sets the receiver’s fetch predicate to predicate.
public void setFetchPredicate(NSPredicate predicate)
Availability
- Available in Mac OS X v10.4 and later.
See Also
setManagedObjectContext
Sets the receiver’s managed object context to managedObjectContext.
public void setManagedObjectContext(NSManagedObjectContext managedObjectContext)
Availability
- Available in Mac OS X v10.4 and later.
See Also
setObjectClass
Sets the object class used when creating new objects.
public void setObjectClass(Class objectClass)
Discussion
NSObjectController’s default implementation assumes that instances of objectClass are initialized using a method that takes no arguments.
Availability
- Available in Mac OS X v10.3 and later.
See Also
validateMenuItem
Validates menu item anItem, returning true if it should be enabled, false otherwise.
public boolean validateMenuItem(_NSObsoleteMenuItemProtocol anItem)
Discussion
For example, if canAdd returns false, menu items with the add action and the receiver as the target object are disabled.
Availability
- Available in Mac OS X v10.3 and later.
© 1997, 2007 Apple Inc. All Rights Reserved. (Last updated: 2007-02-01)