c# create barcode 2: EAAccessory Framework in Objective-C

Encoder QR Code ISO/IEC18004 in Objective-C 2: EAAccessory Framework

CHAPTER 2: EAAccessory Framework
Generate QR Code In Objective-C
Using Barcode drawer for iPhone Control to generate, create QR Code 2d barcode image in iPhone applications.
www.OnBarcode.com
Encoding GTIN - 12 In Objective-C
Using Barcode encoder for iPhone Control to generate, create UCC - 12 image in iPhone applications.
www.OnBarcode.com
auxiliary data fields. Remember that protocol names used by the accessory that you will use in your code must be entered into the project s property list file. Next, you dove down into the details of the three EAAccessory Framework components: the EAAccessory class, the EAAccessoryManager class, and the EASession class. The EAAccessory class references your attached accessory and provides ten properties about it, the most useful being the connected property, the delegate property, and the NSArray protocolStrings property. The EAAccessoryManager provides the list of available accessories to which you can connect. Remember that, as of this writing, Apple permits only a single accessory per iPhone, but that it still must be dealt with as the element in the NSArray. Finally, I covered the methods and properties associated with establishing an EASession which is the logical communications path between the accessory and your iPhone application.
Drawing QR In Objective-C
Using Barcode creation for iPhone Control to generate, create Quick Response Code image in iPhone applications.
www.OnBarcode.com
Printing Barcode In Objective-C
Using Barcode encoder for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
KEY POINTS
Generating Code 3/9 In Objective-C
Using Barcode generator for iPhone Control to generate, create Code 39 image in iPhone applications.
www.OnBarcode.com
Generate GTIN - 128 In Objective-C
Using Barcode printer for iPhone Control to generate, create EAN 128 image in iPhone applications.
www.OnBarcode.com
A Framework is a hierarchical directory containing shared resources such as a library, nib files, images, strings, header files, and even documentation. The overloaded term protocol refers both to the set of methods required to support communications between objects as well as the set of rules governing the communications over a logical connection. When developing code for external accessories, you will use both forms of protocols. The EAAccessory framework consists of the EAAccessory class, the EAAccessoryManager class, and the EASession class. You subclass EAAccessory to reference the accessory to which you are connecting. The most useful properties of the EAAccessory class are the connected property, the delegate property, and the NSArray protocolStrings property. The EAAccessoryManager provides the list of available accessories to which you can connect. NSStreams handle the communications between the iPhone application and the accessory. Both an NSInputStream and an NSOutputStream are required. Before you can use your accessory, an EASession must be established.
Draw EAN13 In Objective-C
Using Barcode creator for iPhone Control to generate, create EAN / UCC - 13 image in iPhone applications.
www.OnBarcode.com
UCC - 12 Creator In Objective-C
Using Barcode drawer for iPhone Control to generate, create UPC - E0 image in iPhone applications.
www.OnBarcode.com
EA Framework Design Patterns
Recognizing QR Code JIS X 0510 In C#
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
QR Code Generator In VB.NET
Using Barcode generator for .NET Control to generate, create QR Code image in .NET framework applications.
www.OnBarcode.com
Now that the guts of the EAAccessory framework have been covered, I want to look at some templates, or design patterns, for common functionality that you will be using. By working through several common design patterns now, you will be able to quickly grasp the finer points of what s going on in subsequent chapters and not get buried. I will begin with the usual suspects: MVC, delegation, singletons, and notifications. You may be familiar with some or all of these from your previous iPhone application development. I m going to focus on how they are used with the EAAccessory framework. After reviewing these standard design patterns, I am going to describe what I have chosen to call the EA Pattern. The EA Pattern is really nothing more than the judicious use of the common Cocoa patterns in a structured format. Think of it like the difference between frameworks and libraries. Just as a framework is a hierarchical structure that includes libraries as well as other elements, our EA Pattern will include lower-level design patterns organized into a hierarchy of its own.
USS Code 39 Drawer In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create Code-39 image in Visual Studio .NET applications.
www.OnBarcode.com
GTIN - 13 Drawer In Objective-C
Using Barcode drawer for iPad Control to generate, create EAN-13 image in iPad applications.
www.OnBarcode.com
Object-Oriented Programming
Barcode Creation In Java
Using Barcode creation for Eclipse BIRT Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
Barcode Generation In None
Using Barcode encoder for Word Control to generate, create Barcode image in Word applications.
www.OnBarcode.com
No discussion of design patterns would be complete without paying allegiance to its predecessor, object-oriented programming (OOP). We all should understand what OOP is and how it differs from what we did in ancient times: functional programming. In a nutshell, before OOP, we programmers looked at the problem, broke it down into its constituent parts, created a map of how those parts fit together, implemented the various pieces, and put them all together. Table 3 1 describes this process along with the common terminology.
Printing Code39 In None
Using Barcode creator for Online Control to generate, create USS Code 39 image in Online applications.
www.OnBarcode.com
Generate EAN-13 In VS .NET
Using Barcode generation for Reporting Service Control to generate, create EAN13 image in Reporting Service applications.
www.OnBarcode.com
CHAPTER 3: EA Framework Design Patterns
Creating PDF417 In Java
Using Barcode printer for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
EAN / UCC - 14 Encoder In Objective-C
Using Barcode generation for iPad Control to generate, create GS1 128 image in iPad applications.
www.OnBarcode.com
Table 3 1. Functional System Design
Create Code 3 Of 9 In Java
Using Barcode generator for Java Control to generate, create Code 39 image in Java applications.
www.OnBarcode.com
Generating ECC200 In C#.NET
Using Barcode generation for VS .NET Control to generate, create Data Matrix image in .NET framework applications.
www.OnBarcode.com
What We Did
Looked at the problem Broke down the problem into its constituent parts Created a map of how all the parts fit together Implemented the various pieces Put them all back together
What We Called It
System Analysis Functional Decomposition
Systems Design or Systems Architecture Unit Code and Test Systems Integration and Test
This process tended to work really well, in the beginning. The problems began as soon as whatever was designed needed to be changed. Take the scenario where John, an experienced individual in the programming department of a printer manufacturer, is asked to design and implement a computerized system for moving completed printers from the assembly area to the shipping area. John, along with his hardware engineering partner, go out to the manufacturing floor and observe, talk to people, ask questions, and so forth. They get an idea of what is going on. They decide what works, what doesn t, what can be added, what can be subtracted, what can change, and so on. They break the process down into the constituent parts and decide how all that should go back together. They come up with a design that utilizes hardware consisting of computers, switches, conveyors, marking systems, and so on. John begins working on his software design while his hardware counterpart puts in all the hardware. At night, when the floor is closed, John and the engineering team go out to the floor, install the software, and after a lot of trial and error achieve project completion. They re rewarded and productivity on the line improves and everything goes well. Two years later, the success of the low-cost printer the company has been selling gives rise to several new models. Rather than making individual lines for each printer, the company wants to maximize use of its skill base. They want the power supply guy to do all the power supplies for all the printers and not hire three different power supply workers. In general, for each functional area of manufacturing, they want to reuse the skill set for the new printers. Another problem surfaces in that these new printers are laser printers whereas the old printer was a line printer. So, the company adds a section of the assembly area for laser subassembly. They ask Chris, a new programmer who took over John s position, to make the changes to the software for the new lines.
Copyright © OnBarcode.com . All rights reserved.