IOS comes with frames

Foundation framework: Provides OC base classes (eg:nsobject), basic data types

UIKIt framework: Creating and managing Application interfaces

Quartzcore: Provides animation effects and the ability to render through hardware

Coregraphics: C-based API for 2D rendering

SystemConfiguration: Detects if the current network is available and hardware device status

Avfoundation: Provides the underlying API for audio recording and playback, as well as managing audio hardware

Cfnetwork Access and configure networks, such as HTTP, FTP, and Bonjour Services

Corefoundation: Provides abstract common data types such as Unicode strings, XML, URLs, etc.

Corelocation: Get location information using GPS and WiFi

Gamekit: Provides network functions for games, point-to-point interconnection and in-Game voice communication

Address Book: Provides access to user contact information

Addressbookui: Provides a user interface for displaying contact information stored in the Address Book

Audiotoolbox: Provides the underlying API for audio recording and playback, as well as managing audio hardware

AudioUnit: Provides an interface that allows our applications to process audio

Mapkit: An interface that provides an inline map for an application

MediaPlayer: Provides the ability to play video and audio

Messageui: Provides a view control interface to handle e-mail and SMS

Opengles provides animation effects and the ability to render through hardware

Storekit: Provides support for application consumption during program operation

IOS System Architecture

iOS is UNIX-based and relatively stable

IOS system architecture can be divided into four levels (from the bottom up)

1. Core OS layer: (Core OS) It includes memory management, file management, power management, and some other operating system tasks. It can interact directly with the hardware device.

2. Core Services we can access some of the iOS services, such as network connectivity, file access, databases, user targeting, and more.

3. Media layer through which we can use various media files in the application, for audio recording of video, drawing of graphics, as well as animating the basis of production.

4. Touch Layer (CoCoa touch) It is responsible for user touch interaction on iOS devices.

IOS comes with frames