iOS System Frameworks

Apple System Frameworks

iOS System Layers

• Cocoa Touch Layer
• Media Layer
• Core Services Layer
• Core OS Layer

Details of Each Layer

• Cocoa Touch Layer
  • UIKit (UI-related)
  • EventKit (calendar events and reminders)
  • Notification Center
  • MapKit (map display)
  • Address Book (contacts)
  • iAd (advertising)
  • Message UI (email and SMS display)
  • PushKit (new push mechanism in iOS 8)

• Media Layer

  • Graphics engines

    • Core Graphics
    • Core Image
    • Core Animation
    • OpenGL ES

  • Audio engines

    • Core Audio
    • AV Foundation
    • OpenAL

  • Video engines

    • AV Foundation
    • Core Media)

• Core Services Layer
  • CFNetwork (network access)
  • CoreData (data storage)
  • CoreLocation (location services)
  • CoreMotion (accelerometer and gyroscope)
  • Foundation (fundamentals such as NSString)
  • Webkit (browser engine)
  • JavaScript (JavaScript engine)

• Core OS Layer
  • OS kernel services (BSD sockets, I/O access, memory allocation, file system, math computations, etc.)
  • Local authentication (fingerprint verification, etc.)
  • Security (interfaces for managing certificates, public keys, secret keys, etc.)
  • Accelerate (performs math, large-number, and DSP computations; these interfaces match iOS device hardware)

Several Key Frameworks

1. Foundation

   • Provides basic system services for all applications
   • UIKit in your applications is built on top of the Foundation framework.
   • The Foundation framework is an Objective-C wrapper around many of the features of the Core Foundation framework.
   • With Foundation you can:
     • Create and manage collections, such as arrays and dictionaries
     • Access images and other resources stored in the app
     • Create and manage strings
     • Post and receive notifications
     • Create date and time objects
     • Automatically discover devices on an IP network
     • Work with URL streams
     • Run asynchronous code

2. UIKit

   • The framework provides classes for building touch-based user interfaces
   • All iOS apps are based on UIKit; you cannot take your app out of this framework.
   • UIKit provides mechanisms for drawing on screen, capturing events, and creating standard interface elements.
   • UIKit also organizes complex projects by managing the components displayed on screen.
   • With UIKit you can:
     • Build and manage your user interface
     • Handle touch and motion-based events
     • Present text and web content
     • Optimize your app for multitasking
     • Create custom interface elements

3. CoreData

   • The framework manages your application’s data model
   • Core Data provides object management; with CoreData you can create model objects and manage them.
   • You manage the relationships between these objects and change the data.
   • CoreData’s built-in SQLite technology manages data efficiently.
   • With Core Data you can:
     • Store and fetch objects in the store
     • Provide basic undo/redo
     • Automatically validate property values
     • Filter, group, and optimize data in memory
     • Manage results in table views with [NSFetchedResultsController]
     • Support document-based applications

4. The Core Graphics framework helps you create graphics

   • High-quality graphics matter to every iOS app.
   • The simplest and fastest way to create graphics in iOS is to use the pre-rendered views and controls provided by the UIKit framework and let UIKit and iOS handle the drawing.
   • When you need to create complex graphics, Core Graphics offers lower-level libraries to help.
   • With Core Graphics you can:
     • Create path-based drawing
     • Anti-aliased rendering
     • Add gradients, images, and colors
     • Use coordinate-space transformations.
     • Create, display, and analyze PDF documents

5. Core Animation lets you create advanced animations and visual effects

   • UIKit provides animations built on top of Core Animation.
   • If you need capabilities beyond what UIKit offers, you can use Core Animation directly.
   • The Core Animation interfaces are part of the QuartzCore framework.
   • With Core Animation you can create nested objects and manipulate, rotate, scale, and transform them.
   • With Core Animation you can create dynamic user interfaces without resorting to lower-level graphics APIs such as OpenGL ES.
   • With Core Animation you can:
     • Create custom animations
     • Add timing functions and graphics
     • Support frame animations
     • Specify graphical layout constraints.
     • Group multiple-layer changes into anatomic update.

6. The OpenGL ES framework provides 2D and 3D drawing tools

   • OpenGL ES supports 2D and 3D drawing; Apple’s OpenGL ES implementation leverages the hardware to deliver high-speed, full-screen, game-style applications.
   • With OpenGL ES you can:
     • Create 2D and 3D graphics
     • Create more complex graphics, such as data visualization, flight simulators, or video games
     • Access the underlying graphics hardware

These make up the skeleton of iOS/macOS the architecture at its highest level.