IOS Technology Overview_introduction

About iOS technology

iOS is an operating system that runs on IPad,iphone and iPod touch devices. This operating system manages the hardware of these devices and provides the technology needed to implement native apps. The operating system also comes with a number of system apps, such as Phone,mail and Safari, which provide users with standard system services.

The iOS Software development tool (SDK) contains tools and interfaces for developing, installing, running, and testing native apps that run on iOS devices. Native apps are developed using the iOS system framework and the OBJECTIVE-C language and can be run directly on iOS. Unlike web apps, native apps are installed locally, so even when the device is in flight mode, it still provides users with effective services. These apps are installed with the System app and the app itself and the user's data can be synced to the user's computer via itunes.

Note: You can use HTML,CSS and JavaScript encoding in iOS to create a web app. Web apps run in Safari, Web Apps require a network connection to use network services. This document does not include content for creating Web apps. For more information on creating Web apps, see Safari Web Content Guide.

Overview

The IOS SDK provides resources for developing native apps. Understanding the techniques and tools in the SDK can help you make better choices when thinking about how to design and implement your application.

iOS is a layered structure

At the highest level, iOS plays a role in the media between the underlying hardware and the apps you create. The app does not communicate directly with the underlying hardware. Instead, the app communicates with the hardware through a defined set of system interfaces. These interfaces make it easy to create apps that can work on devices with different hardware performance.

The technical implementation of iOS can be seen as a combination of levels, as shown in. Low tiers include basic services and technologies. High-level and built on a low-level basis, they provide more complex services and technologies.

When you write code, it is recommended to use a high-level framework. The high-level framework provides an abstraction of the object-oriented underlying structure. These abstractions generally make coding simpler because of the reduced number of code that must be written or used to encapsulate potentially very complex features, such as sockets and threads. You can also use a low-level framework if you have a low-level framework that contains some techniques that are not exposed in the upper layers and frameworks.

Keywords: Cocoa Touch layer, Media layer, core Services layer, core OS layer

iOS technology is packaged as a framework

Most of the system interfaces provided by Apple are within a special package, which is called a framework. A framework is a dictionary that contains resources (such as header files, images, and ancillary applications) for a dynamic shared library and supporting libraries. When using the framework, you can add these frames to your project through Xcode.

Keyword: IOS frameworks

The developer library can help you

The iOS Developer Library is a very important resource to use when developing. The library contains API references, programming instructions, Release notes, technical documentation, code examples, and other resources that provide tips and guidelines to help you create your app in the best possible way.

You can use the iOS Developer Library on the Apple Developer website or from Xcode. In Xcode, choose Help > Documentation and API Reference to open the Xcode document window, which is a central resource for developing information using iOS. You can use the document window to browse, search, and mark documents.

How to use Documents

iOS Technology Overview This article is a getting Started guide for all the people who are just beginning to develop on the iOS platform. It provides an overview of the technology and tools that have an impact on the development process and provide links to relevant documentation and other sources of information. You should use the documentation like this:

• Adapt yourself to the iOS platform

• Learn about iOS software technology and think about why you want to use these technologies, and when to use them

• Understand the development opportunities of the Platform

• Get advice and guidance on getting to the iOS platform from other platforms

• Find key documents relevant to the technology you are interested in

This article does not provide information about user-level features, nor does it affect the software development process, and it is not possible to list specific iOS device hardware performance. The new developer should know that this article is used to familiarize with iOS. An experienced engineer can take this article as a map for exploring techniques and developing techniques.

See Also

If you are just in touch with iOS development, this book can only provide an overview of the system. To learn more about iOS app development, you need to read the following documentation:

· Start developing IOS Apps today provides guidance throughout the development process, from how to configure your system to the process of submitting your app to the App Store. If you're just starting out with iOS app development, this will be another starting point to explore iOS development.

iOS Human Interface Guidelines provides guidance and information on how to design your user interface

· APP Distribution Guide, which describes the development process of iOS from the perspective of development tools. This article describes the required configuration and device configuration for development, and also includes the use of Xcode and other tools to create, run, and test your software.

Developed on Apple devices, you register and pay for the iOS developer program, then configure a device for development. After you sign up, you'll get a backup of Xcode and iOS SDK in iOS Dev Center.

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About the IOS Technologies

IOS is the operating system-runs on IPad, IPhone, and iPod touch devices. The operating system manages the device hardware and provides the technologies required to implement native apps. The operating system also ships with various system apps, such as Phone, Mail, and Safari, which provide standard system SE Rvices to the user.

The IOS Software Development Kit (SDK) contains the tools and interfaces needed to develop, install, run, and test native Apps that appear on an IOS device's Home screen. Native apps is built using the iOS system frameworks and Objective-c language and run directly on IOS. Unlike web apps, native apps is installed physically on a device and is therefore always available to the user, even whe n the device is in airplane mode. They reside next to other system apps, and both the app and any user data are synced to the user ' s computer through ITunes.

Note: It is possible to create Web apps using a combination of HTML, cascading style sheets (CSS), and JavaScript code. Web apps run inside the Safari Web browser and require a network connection to access your Web server. This document does not cover the creation of web apps. For more information on creating Web Apps in Safari, see the Safari web Content Guide.

At a Glance

The iOS SDK provides the resources you need to develop native IOS apps. Understanding a little about the technologies and tools contained in the SDK can help you make better choices Design and implement your apps.

The IOS Architecture is layered

At the highest level, IOS acts as a intermediary between the underlying hardware and the apps you create. Apps don't talk to the underlying hardware directly. Instead, they communicate with the hardware through a set of well-defined system interfaces. These interfaces make it easy-to-write apps that work consistently on devices have different hardware capabilities.

The implementation of IOS technologies can be viewed as a set of layers, which is shown in Figure I-1. Lower layers contain fundamental services and technologies. Higher-level layers build upon the lower layers and provide more sophisticated services and technologies.

As you write your code, it's recommended that's prefer the use of higher-level frameworks over Lower-level frameworks W Henever possible. The higher-level frameworks is there to provide object-oriented abstractions for lower-level constructs. These abstractions generally make it much easier to write code because they reduce the amount of code that has to write a D encapsulate potentially complex features, such as sockets and threads. Lower-level frameworks and technologies, too, if they contain features not exposed by the higher-level Framewo Rks.

Relevant chapters: Cocoa Touch layer, Media layer, core Services layer, core OS layer

The IOS Technologies is Packaged as frameworks

Apple delivers most of its system interfaces in special packages called frameworks. A framework is a directory that contains a dynamic shared library and the resources (such as header files, images, and Hel Per apps) needed to support the that library. To use frameworks, you add them to your app for project from Xcode.

relevant sections: IOS Frameworks

The Developer Library is there

The IOS Developer Library is a important resource for your use during development. The library contains API reference, programming guides, Release notes, tech notes, sample code, and many other resources O Ffering tips and guidance about the ' best ' to create your apps.

You can access the IOS Developer Library from the Apple Developer website or from Xcode. In Xcode, choose Help > Documentation and APIs Reference to display the Xcode documentation window, which are the central Resource for accessing information about IOS development. Use the Documentation window to browse, search, and bookmark documents.

How to use the This Document

iOS Technology Overview is a introductory guide for anyone of the new to the iOS platform. It provides an overview of the technologies and tools that has an impact on the development process and provides links to Relevant documents and other sources of information. You should use the This document to:

• Orient yourself to the IOS platform
• Learn about IOS Software Technologies, why do you might want to use them, and when
• Learn about development opportunities for the platform
• Get tips and guidelines on what to move to IOS from other platforms
• Find key documents relating to the technologies is interested in

This document does not provide information for User-level features that has no impact on the software development Proce SS, nor does it list the hardware capabilities of specific IOS devices. New developers should find this document useful for getting familiar with IOS. Experienced developers can use it as a road map for exploring specific technologies and development techniques.

See Also

If you ' re new to IOS development, this book provides only a overview of the system. To learn the develop IOS apps, you should read the following documents:

• a target= "_self" Start developing IOS Apps today/a provides a guided to ur of the development process, starting with what to set up your system and ending with the process of how to submit apps t o the App Store. If you were new to developing iOS apps, the This is another good starting point for exploring iOS app development.
• ios Human Interface Guidelines provides Guidance and information about what to design your app s user interface.
• app Distribution Guide describes the IOS Development process from the perspective of the tools. This document covers the configuration and provisioning of devices for development and covers the use of Xcode (and other Tools) for building, running, and testing your software.

To develop on a device, your sign up for Apple's paid IOS Developer program and then configure a device for development pur Poses. Obtain a copy of Xcode and the iOS SDK at the iOS Dev Center

IOS Technology Overview_introduction