问题
I have a NSTableView
populated by a Core Data entity and Add Item / Remove Item buttons all wired with a NSArrayController
and bindings in Interface Builder.
The Undo/Redo menu items can undo or redo the add / remove item actions.
But the menu entries are called only „Undo“ resp. „Redo“.
How can i name them like „Undo Add Item“, „Undo Remove Item“, etc.
(I am aware, something similar was asked before, but the accepted answers are either a single, now rotten link or the advice to subclass NSManagedObject and override a method that Apples documentation says about: "Important: You must not override this method.“)
回答1:
Add a subclass of NSArrayController as a file in your project. In the xib, in the Identity Inspector of the array controller, change the Class from NSArrayController
to your new subclass.
Override the - newObject
method.
- (id)newObject
{
id newObj = [super newObject];
NSUndoManager *undoManager = [[[NSApp delegate] window] undoManager];
[undoManager setActionName:@"Add Item"];
return newObj;
}
Also the - remove:sender
method.
- (void)remove:(id)sender
{
[super remove:sender];
NSUndoManager *undoManager = [[[NSApp delegate] window] undoManager];
[undoManager setActionName:@"Remove Item"];
}
回答2:
Register for NSManagedObjectContextObjectsDidChangeNotification:
[[NSNotificationCenter defaultCenter] addObserver: self
selector: @selector(mocDidChangeNotification:)
name:NSManagedObjectContextObjectsDidChangeNotification
object: nil];
And parse the userInfo dictionary in the corresponding method:
- (void)mocDidChangeNotification:(NSNotification *)notification
{
NSManagedObjectContext* savedContext = [notification object];
// Ignore change notifications for anything but the mainQueue MOC
if (savedContext != self.managedObjectContext) {
return;
}
// Ignore updates -- lots of noise from maintaining user-irrelevant data
// Set actionName for insertion
for (NSManagedObject* insertedObject in
[notification.userInfo valueForKeyPath:NSInsertedObjectsKey])
{
NSString* objectClass = NSStringFromClass([insertedObject class]);
savedContext.undoManager.actionName = savedContext.undoManager.isUndoing ?
[NSString stringWithFormat:@"Delete %@", objectClass] :
[NSString stringWithFormat:@"Insert %@", objectClass];
}
// Set actionName for deletion
for (NSManagedObject* deletedObject in
[notification.userInfo valueForKeyPath:NSDeletedObjectsKey])
{
NSString* objectClass = NSStringFromClass([deletedObject class]);
savedContext.undoManager.actionName = savedContext.undoManager.isUndoing ?
[NSString stringWithFormat:@"Insert %@", objectClass] :
[NSString stringWithFormat:@"Delete %@", objectClass];
}
}
I've tested this in my own code-- it's rough. Can spend a lot more time making the actionName nicer. I deleted parsing of updates because: 1) insertions and deletions of objects in to-many relationships generate updates of other objects 2) I don't care to figure out how to discover what properties changed at this time
I also have class names that aren't user-friendly, so this is a great time to implement the description function for all entities, and use that rather than the class name.
But this at least works for all object controllers in a project, and easily enough for insert and delete.
[edit] Updated with mikeD's suggestion to cover redo having an inverse name. Thanks!
来源:https://stackoverflow.com/questions/23687651/how-to-name-undo-menu-entries-for-core-data-add-remove-items-via-bindings-and-ns