iOS 15 Programming Fundamentals with Swift

Part III. Cocoa

The Cocoa Touch frameworks provide the general capabilities needed by any iOS application. Buttons can be tapped, text can be read, screens of interface can succeed one another, because Cocoa makes it so. To use the framework, you must learn to let the framework use you. You must put your code in the right place so that it will be called at the right time. You must fulfill certain obligations that Cocoa expects of you. You master Cocoa by being Cocoa’s obedient servant. In this part of the book, that’s what you’ll learn to do.

• Chapter 11 describes how Cocoa is organized and structured through such Objective-C language features as subclassing, categories, and protocols. Then some important built-in Cocoa object types are introduced. The chapter concludes with a description of Cocoa key–value coding and a look at how the root NSObject class is organized.

• Chapter 12 presents Cocoa’s event-driven model of activity, along with its major design patterns and event-related features — notifications, delegation, data sources, target–action, the responder chain, and key–value observing. The chapter concludes with some words of wisdom about managing the barrage of events Cocoa will be throwing at you, and how to escape that barrage momentarily with delayed performance.

• Chapter 13 is about Cocoa memory management. I’ll explain how memory management of reference types works. Then some special memory management situations are described: autorelease pools, retain cycles, ...