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The overall purpose of the network of objects is to expedite the work of the event and drawing cycle. Figure 6-1 (which you may recall from “Adding Behavior to a Cocoa Program”) illustrates this cycle.
The application presents a graphical user interface; users interact with that interface by using the mouse and keyboard to enter data or indicate a choice; and this input is transformed into an event that is routed to the application and placed in its event queue. For each event in its queue, the application locates the object or objects best suited to handle the event, and after the event is handled the application may appropriately modify what it displays to users. Then the application gets the next event in its queue and the cycle begins again.
The core objects that participate in this architecture are direct or indirect descendants of the NSApplication, NSWindow, and NSView classes.
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© 2006 Apple Computer, Inc. All Rights Reserved. (Last updated: 2006-12-20)
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