"iOS learning" 1.IOS framework

1. Framework Overview

The system architecture of iOS is divided into four tiers: the core OS layer, the core service layer, the media layer, and the Cocoa touch layer. The following is an iOS system diagram.

• Core OS is the bottom layer of the iOS system architecture, which includes memory management, file systems, power management, and some other operating system tasks. It can interact directly with the hardware device. As an app developer, you don't have to deal with this layer.
• Core Services is the central service layer through which you can access some of the services of iOS.
• Media layer, through which we can use a variety of media files in the application, for audio and video recording, graphic drawing, as well as the production of basic animation effect.
• Cocoa Touch is a touch layer, a layer that provides a variety of useful frameworks for our application development, and most of it is about the user interface, which is essentially responsible for the user's touch interaction on the iOS device.

2.CocoaTouch Layer

Cocoatouch provides basic system behavior support, and minimizes your workload, and when you want to implement more complex behaviors and interfaces, consider seeking technical support from the bottom down.

• Uikit Framework: Uikit provides some of the key objects necessary for a program to run, allowing the app to capture user input and display content on the screen.

Uikit Framework Class Organization chart:

As can be seen in the figure, the responder class is the root class of the largest branch in the graph, and Uiresponder defines the interface and default behavior for handling response events and response chains. When the user scrolls through the list with a finger or enters on a virtual keyboard, the Uikit generates time to transmit to the uiresponder response chain until an object in the chain handles the event. The corresponding core objects, such as: UIApplication, Uiwindow,uiview are inherited directly or indirectly from Uiresponder.

• Mapkit Framework: IOS3.0 introduces the framework, which provides a map interface that can be embedded in the application, which contains a map view that can be scrolled.
• Address Book UI Framework: IOS3.0 introduces the framework that can be used to compose e-mail messages and place them in the user's Outbox queue for sending
• Message UI Framework: Displays the standard system interface for creating or editing contacts

3.Media Layer

Includes graphics, audio, video and other technologies

Quartz Core framework: Contains the core animation interface. Core animation is a high-level animation and blending technology that uses optimized render paths for complex animations and visual effects.

Media Player framework: Applications play video and audio content.

AV Foundation framework: The framework contains OBJECTIVE-C classes that can be used to play audio content.

Core Graphics frame: Contains the Quartz 2D drawing API interface.

4.Core Service Layer

• Fundation Frame

Foundation Class Organization Chart Note: The Gray in the figure is not supported by iOS

The classes in the foundation framework are logically categorized as follows:

1. Value Object
2. Collection
3. Operating system services include the following three: File system and URL interprocess communication. most of the classes in this category represent different system ports, sockets, and name servers, and are useful for implementing the underlying IPC.   Nspipe represents a BSD pipeline, a one-way communication channel between processes. threads and sub-tasks. the Nsthread class allows you to create multithreaded programs, while various lock classes provide a variety of control mechanisms for competing threads when accessing process resources. With Nstask, your program can separate a sub-process to perform other work or monitor progress.
4. Notice
5. Archiving and serialization
6. Expressions and conditional judgments
7. Objective-c Language Services

Reference:

http://blog.csdn.net/yuhuangc/article/details/7575519

http://blog.csdn.net/totogo2010/article/details/8081253

"iOS learning" 1.IOS framework