iOS Succinctly, Syncfusion

Mobile applications are one of the fastest growing segments of the technology industry, and the iPhone and iPad have been at the forefront of the mobile revolution. Developing applications for these platforms opens the door to a vast number of mobile users. Unfortunately, the variety of underlying technologies can be overwhelming for newcomers to iOS, and the 1,500+ official help documents available from the iOS Developer Library don’t exactly provide an approachable introduction to the platform. The goal of iOS Succinctly is to provide a concise overview of the iOS landscape.

iOS and the iOS SDK

iOS is the operating system behind iPhone and iPad applications. It takes care of the low-level system tasks like managing memory, opening and closing applications, and rendering pixels to the screen. On top of this core operating system rests a collection of frameworks, which are C and Objective-C libraries that provide reusable solutions to common programming problems. For example, the UIKit Framework defines classes for buttons, text fields, and several other user interface components. Instead of implementing your own buttons from the ground up, you can leverage the existing UIButton class.

Together, the core operating system and these higher-level frameworks compose the iOS software development kit (SDK). The goal of the iOS SDK is to let you focus on developing what your application does instead of getting bogged down by how it does it. The SDK is divided into layers based on what level of abstraction they provide. These layers, along with some of the popular frameworks they contain, are shown in the following diagram: