November 2011
Intermediate to advanced
528 pages
10h 14m
English
Content preview from Cocoa® Programming for Mac® OS X, Fourth EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 9. NSUndoManager
Using NSUndoManager, you can add undo capabilities to your applications in a very elegant manner. As objects are added, deleted, and edited, the undo manager keeps track of all messages that must be sent to undo these changes. As you invoke the undo mechanism, the undo manager keeps track of all messages that must be sent to redo those changes. This mechanism works by utilizing two stacks of NSInvocation objects.
This is a pretty heavy topic to cover so early in a book. (Sometimes when we think about undo, our heads start to swim a bit.) However, undo interacts with the document architecture. If we tackle this work now, you will see in the next chapter how the document architecture is supposed to work.
NSInvocation
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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