Wiley Professional iPhone Programming with MonoTouch and .NET/C#
Contents
1. limited purpose functions but they should not do everything that a desktop application does gt The iPhone simulator is a fine tool but don t limit testing to the iPhone simulator A simulator is just a simulator There is a keyboard and a mouse associated with the iPhone simulator To really test a complicated design the application must be tested from a physical iPhone APPLE IPHONE SDK TOOLS When the iPhone originally shipped you could not run third party native applications directly on the device until March 6 2008 when Apple released the first beta of the SDK The iPhone SDK allows third parties to write applications and run them natively on the device Since that date there have been a steady stream of updated beta and released versions of the iPhone SDK Originally the iPhone SDK supported both the iPhone and the iPod Touch With the beta release of the iPhone SDK Version 3 2 Apple added support for the iPad tablet device Tools The Apple SDK contains a number of tools that are important to the MonoTouch developer These tools are gt Xcode A suite of tools for development in an Apple environment the main tool being the IDE Although MonoTouch does not directly use the Xcode IDE it can help you create a simple app to deploy to a device You can also use it to verify that the certificates and provi sioning information on the associated devices are working properly gt Interface Builder Interface Builder IB a2. Jailbreaking requires the iPhone s owner to perform the operation and many iPhone users are not technically proficient enough to do this gt Legality The legality of jailbreaking is unclear at the time of this writing It is not clear where jailbreaking falls within the Digital Millennium Copyright Act The Electronic Frontier Foundation has asked the United States Copyright Office to recognize an exception to the DMCA that allows iPhone owners to jailbreak their devices Apple has argued in response that jailbreaking an iPhone is a copyright violation gt Unknowns It comes with a series of unknowns How well can a jailbroken iPhone be upgraded to new versions of the iPhone operating system OS Will jailbreaking an iPhone open it up to security issues In 2008 Apple introduced the second generation of the iPhone referred to as the iPhone 3G With this generation and the new version of the iPhone OS Apple released a number of enhancements including the ability to run applications natively on the device In addition to this Apple has put together an eco system whereby users can find and install applications on their iPhone device called the App Store These native applications are a great improvement over web based applications which are limited in what they can do on a device Fundamentally they have to be loaded over the Web and are not able to access all device features Native applications tend to have more support for device fea
3. The iPhone operating system does not allow for software code that is interpreted or dynami cally compiled in any way gt Apple s licensing for the SDK and developing with the iPhone does not allow for applications to have interpreted or dynamically compiled code gt Apple has an extensive validation process for iPhone applications Some of the automated tests for an application will check for dynamically compiled and interpreted code These issues and licensing are something that developers need to be knowledgeable of and some what limit the choices that a developer has for writing applications that run on the iPhone MOBILE DEVELOPMENT There are a few things developers need to know when building applications on the iPhone with MonoTouch gt The iPhone has a startup timer If an application takes longer than 20 seconds to start up the iPhone OS kills it gt The iPhone OS will kill any application that is unresponsive for longer than 20 seconds while the application is running To work around this you need to perform some type of asynchro nous operation gt The time spent processing the FinishedLaunching event counts against the startup timer As a result you do not want any long term synchronous processing in the FinishedLaunching event gt The iPhone simulator is good for initial testing however it is not necessarily accurate for all testing Just because something works in the simulator doesn t mean it wil
4. designed to be a smartphone that provided web browsing 6 CHAPTER1 INTRODUCTION TO IPHONE DEVELOPMENT WITH MONOTOUCH FOR C DEVELOPERS e mail and multimedia capabilities The first generation iPhone connected to a wireless network and applications were delivered to the user over the mobile version of Safari Writing a web based application for the iPhone is fairly simple The Safari web browser is a great tool it does an excellent job of scaling web based applications to run an iPhone sized screen It also does well running applications that are highly dependent on JavaScript Upgrading an iPhone web based application is also a simple matter of deploying a new version of the application to a web server Many applications have taken this approach Unfortunately web applications are not suitable for all applications applica tions that require some background processing access to local resources must work when a network connection is unavailable and some other application types don t work well in this model So the question becomes how does one write an application that fits into the iPhone The first generation iPhone did not have support for users to load applications on the device For a few users this was not acceptable and they began jailbreaking their iPhones which is the process where users run software on their devices that Apple has not approved Jailbreaking has several problems gt Technical Issues
5. Introduction to iPhone Development with MonoTouch for C Developers WHAT S IN THIS CHAPTER The history of the iPhone and its mindshare A short history of Mono and its relationship to the NET Framework How MonoTouch opens the iPhone to NET Developers yv yv y Why MonoTouch is so attractive to developers The past several years have seen an amazing growth in the use of smartphones and USA Today recently reported how smartphones have become an indispensable part of people s lives Although Windows based computers running 32 bit x86 or 64 bit x64 processors dominate the desktop computer marketplace and the NET Framework is the dominant development environment for the Windows platform no single vendor or platform dominates the mobile device marketplace devices based on Symbian Research in Motion Blackberry Windows Mobile Android and other platforms are available In addition devices may run the same operating system and be presented to the user in separate form factors This fracture in the marketplace is problematic for developers how can they take a development framework or tool that they already know and use that knowledge in a device that has a large and growing market share This chapter looks at how the largest segment of developers can target the smartphone with the highest mindshare and that the smartphone is growing faster in marketshare than any other device 2 CHAPTER1 INTRODUCTION TO IPHONE DEVELOPMENT
6. Mono runs on Mac Linux BSD and other operating systems Product Comparison 3 Mono was officially announced in 2001 and is the brainchild of Miguel de Icaza Mono version 1 0 shipped in 2004 and currently Mono is at Version 2 6 Mono continues to be led by Miguel de Icaza and is under the general leadership and support of Novell As much as there is the desire to match the NET Framework s features this is not possible due to the fact that Microsoft has more resources and a head start in the development of those features At the same time the Mono project has parity with a large number of NET Framework features Along with Mono there is an open source IDE called MonoDevelop which started as a port of the SharpDevelop IDE MonoDevelop began as a project to allow for Mono development on Linux but with the release of MonoDevelop 2 2 the ability to develop with Mono expanded to the Mac Windows and several other non Linux UNIX platforms Though the NET Framework is very popular two issues make it unsuitable for running on the iPhone gt At some level Apple and Microsoft are competitors and are likely not too excited to work together gt The NET Framework fundamentally is dynamically compiled at runtime This is the just in time compilation of the NET Framework This is a violation of the Apple license and the operating principles of the iPhone OS Given that code running on the Microsoft NET Framework is compiled to ma
7. WITH MONOTOUCH FOR C DEVELOPERS PRODUCT COMPARISON This section takes a quick look at NET Framework Mono and MonoTouch three products that have allowed the largest segment of developers to target the iPhone the most exciting mobile plat form currently in the marketplace NET Framework In the late 1990s Microsoft began work on the NET Framework The first version of the framework shipped in 2002 Microsoft proceeded to introduce subsequent versions of the NET Framework and has recently introduced the NET Framework 4 The NET Framework comes in various versions including 32 bit versions 64 bit versions a version for the XBOX gaming plat form and a version for Microsoft s mobile devices referred to as the Compact Framework CF A few facts about NET Framework gt Microsoft released a development tool Visual Studio NET with the Framework This tool is the Integrated Development Environment for NET gt It s based on a virtual machine that executes software written for the framework This vir tual machine environment is referred to as the Common Language Runtime CLR and it is responsible for security memory management program execution and exception handling gt Applications written in the INET Framework are initially compiled from source code such as Visual Basic or C to an intermediate language called MSIL The initial compilation is performed by calling the language specific command line compi
8. chine code at run time using the just in time compilation one would expect that applications written for Mono would have the same behavior and thus not be suitable for running on the iPhone However Mono has a technology that allows for appli cations to be compiled ahead of time referred to as AOT technology A disadvantage of NET Mono and the iPhone is that NET Mono developers cannot take their NET Mono C knowledge and apply it to the iPhone platform As illustrated in Figure 1 1 you see that the reason NET Mono developers can t target the iPhone is because they re two separate entities FIGURE 1 1 MonoTouch In 2009 Novell announced and shipped MonoTouch which allows NET developers to create native iPhone applications in C With MonoTouch applications are compiled into executable code that runs on the iPhone The significance of this should not be understated NET Mono developers can target the iPhone through MonoTouch This is illustrated in Figure 1 2 How does MonoTouch accomplish this Does it somehow allow Windows Forms applications to be translated or recom piled and deployed on the iPhone MonoTouch provides a FIGURE 1 2 4 CHAPTER1 INTRODUCTION TO IPHONE DEVELOPMENT WITH MONOTOUCH FOR C DEVELOPERS NET layer over the native iPhone programming layer present on the iPhone OS referred to as Cocoa Touch Cocoa Touch is based on the Cocoa layer in the Mac OS X and is available on the iPh
9. dated to use CoreGraphics and to only expose the functionality available on the iPhone In addition MonoTouch provides a set of additional namespaces that may be important to you These are gt MonoTouch AddressBook MonoTouch CoreGraphics MonoTouch AddressBookUI MonoTouch AudioToolbox MonoTouch MapKit MonoTouch MediaPlayer MonoTouch AVFoundation MonoTouch MediaPlayer MonoTouch CoreAnimation Vv VV VV VV Y MonoTouch SystemConfiguration These namespaces are fairly self explanatory in their functionalities and are specific to the iPhone MonoDevelop MonoDevelop is a free IDE used for developing with Mono and is an early branch of the SharpDevelop IDE Originally MonoDevelop ran only on Linux but with version 2 2 MonoDevelop began running on the Mac MonoDevelop on the Mac allows for the creation and management of iPhone projects as well as debugging and deployment to the simulator and devices for testing iPhone There s no doubt that Apple has changed the mobile device marketplace since the introduction of the original iPod in 2001 Although the iPod was not the first device to play mp3 files it was the first product that played mp3 files made it easy to use and provided an easy to use marketplace to pur chase audio files The iPod really caused the mp3 device marketplace to explode In January 2007 Apple turned the smartphone upside down when it officially announced the first generation iPhone The iPhone was
10. er explores the specifics of building a MonoTouch application with MonoDevelop Chapters 3 and 4 describe how to work with the user controls for user input and for presenting data to a user in a standard form factor Other chapters in the book will explore specific parts of the iPhone such as maps acceleration and the iPad
11. hone MonoTouch Foundation This namespace provides support for the data types necessary to communicate with the Objective C world of the iPhone Most types are directly mapped For example the NSobject Objective C base class is mapped to the MonoTouch Foundation NSObject class in C Some classes are not directly mapped and are instead mapped to their native NET types For example NSString maps to the basic string type and NSArray maps to a strongly typed array MonoTouch UIKit This namespace provides a direct mapping between the UI components within Cocoa Touch The mapping is done by providing NET classes for each UI compo nent and this is the namespace that developers will likely spend most of their time working with For NET developers Cocoa Touch is an abstraction layer or API for building pro grams that run in the iPhone Cocoa Touch is based on the Cocoa API used in building pro grams that run on the Mac OS X operating system Cocoa Touch can be thought of as Cocoa tuned for the touch based iPhone operating system Product Comparison 5 gt OpenTK This namespace is a modified version of the OpenTK API OpenTK is an object oriented binding for OpenGL which stands for the Open Graphics Library OpenGL is an API for using three dimensional graphics OpenTK is a library for performing OpenGL OpenAL and OpenCL It is written in C and runs on Windows Mac OS X and Linux The OpenTK implementation on the iPhone has been up
12. l run in the iPhone in the same way Final testing should be completed in the iPhone 8 CHAPTER1 INTRODUCTION TO IPHONE DEVELOPMENT WITH MONOTOUCH FOR C DEVELOPERS gt With NET executables are fairly small Every application shares the NET Framework so the applications don t have their own copy of the framework MonoTouch is not built into the iPhone and its applications must have their own copy of the framework MonoTouch is compiled into your application The result is that MonoTouch applications are larger on disk than a comparable Objective C application Although MonoTouch is a commercially licensed product it is still a product that is under continual development and MonoTouch may not have support for a specific namespace or assembly You have two options for this situation gt Wait on the implementation of that assembly from the MonoTouch product gt Pull the necessary code or assembly into to your project This is fairly common if the applica tion needs to use code within the system wWeb namespaces In addition to the technical issues of building an application for the iPhone some design issues that developers should be aware of include gt Don t design an application for a desktop environment and think that it can be scaled down to an iPhone or any mobile device An iPhone does not have the display hardware or stor age of a desktop computer iPhone and mobile device applications are really good for simple
13. ler Visual Studio or some other build tool A second compilation set is typically done when an application is executed This second compilation takes the intermediate language and compiles it into executable code that can be run on the operating system This second compilation is referred to as just in time compilation gt It s language independent and numerous languages are available for the Framework In the Visual Studio Microsoft has shipped various languages including Visual Basic F C and C gt It has a series of libraries that provide consistent functionality across the various languages These libraries are referred to as the Base Class Libraries gt Microsoft has submitted various parts of the NET Framework to various standard organiza tions Some of these are the C language the Common Language Infrastructure Common Type System CTS Common Language Specification CLS and Virtual Execution System VES gt It has the largest number of developers for any development framework out there As a result more developers are familiar with the NET Framework than any other development framework gt A disadvantage of the NET Framework is that it is not available for non Microsoft platforms Mono Mono is an open source project that provides a C compiler and Common Language Runtime on non Windows operating systems Mono is currently licensed under GPL version 2 LGPL version 2 the MIT and dual licenses
14. llows for the graphical creation of a user interface The MonoDevelop IDE integrates with IB and converts the interface created within IB into a user interface callable by MonoTouch Summary 9 gt Simulator Allows for emulating the iPhone iPod Touch and the iPad Note that the simula tor does not run ARM code It runs x86 code gt Libraries necessary to target the device This includes libraries for Cocoa Touch audio video networking SQLite threads power management and the general OS X Kernel Licensing The SDK is a free download Unfortunately to release software for the iPhone a developer must join the iPhone Development Program At the time of this writing the cost to join is 99 U S dol lars a year The cost of joining varies from country to country The ability to distribute applica tions to devices is dependent on having the necessary development certificates These are available through the Apple Developer site once a developer joins the iPhone Developer Program SUMMARY This chapter looked at the following items in the marketplace gt The iPhone its licensing and its operating system gt The NET Framework and Mono gt MonoTouch which allows NET developers to target the iPhone gt MonoDevelop which allows developers to have a good IDE to write code with MonoTouch You should now be familiar with which tools are needed to build a native application with NET C for the iPhone The next chapt
15. one iPod Touch and the iPad MonoTouch does not provide a mechanism to cross compile Windows Forms applications but allows developers to build applications that run natively on the iPhone Overall the application programming interface API exposed by the MonoTouch SDK is a com bination of the NET 2 0 Framework s core features the Silverlight 2 0 API and the APIs on the iPhone MonoTouch provides a bridge interop between the iPhone s native APIs based on Objective C and C based APIs to the NET world that C developers are accustomed to MonoTouch Components MonoTouch is made up of the following four components gt gt The Monotouch d11 is a C assembly that provides a binding API into the iPhone s native APIs A command line tool that compiles C and Common Intermediate Language CIL code This compiled code can then be run in the simulator or an actual iPhone An add in to MonoDevelop that allows for iPhone development and for Interface Builder to create graphical applications A commercial license of the Mono runtime which allows for the static linking of the Mono runtime with the code developed Namespaces and Classes MonoTouch provides a rich set of namespaces and classes to support building applications for the iPhone Some of the most popular namespaces and classes are gt MonoTouch ObjCRuntime This namespace provides the interop bridge between the NET C world and the Objective C world of the iP
16. tures like the accelerometer file system camera cross domain web services and other features that are out side of features available in HTML and JavaScript In addition native applications do not depend on the wireless network to be loaded whereas a web application is dependent on the wireless net work for loading Mobile Development 7 In 2009 Apple introduced the iPhone 3GS and version 3 of the iPhone operating system The iPhone 3GS a refinement of the iPhone 3G supports higher data rates than the iPhone 3G an improved camera an updated CPU and voice control In 2010 Apple announced and shipped the iPad The iPad is a tablet device and it has a larger screen than the iPhone Also significant is that it shipped with the iPhone operating system that is fundamentally different than the iPhone Along with the release of each new iPhone Apple has introduced a new iPod touch The iPod touch can be thought of as an iPhone without the phone camera and support for the 3G data services however the iPod touch does have support for wireless networking using WiFi Since its availability three years ago Apple has shipped more than 60 million units of the iPhone The iPad is estimated to ship several million units of the iPad in its first year of availability and this will likely result in the iPad being the most popular tablet in 2010 Unfortunately for developers three issues must be considered when running on the device gt
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