You can run two different types of custom applications on a device, and they are web and native applications. Native applications are installed directly on the device and can run without the presence of a network connection. Web applications use a combination of HTML, CSS, and JavaScript code to implement interactive applications that live on a web server and are transmitted over the network and run inside the Safari web browser.
It does not support the creation of other types of code, such as drivers, background applications, frameworks, or dynamic libraries. If you want to integrate code from a framework or dynamic library into your application, you should link that code statically into your application’s executable file when building your project.
The iPhone SDK supports the creation of native foreground applications that appear on the device’s Home screen only. Main components of the iPhone SDK (just to remind you, every time I write or say iPhone I mean iPod touch to) includs the following:
Xcode Tools – provides the tools that support iPhone application development, including the following key applications:
- Xcode – an integrated development environment that manages your application projects and lets you edit, compile, run, and debug your code. Xcode integrates with many other tools and is the main application you use during development.
- Interface Builder – a tool you use to assemble your user interface visually. The interface objects you create are then saved to a special resource file format and loaded into your application at runtime.
- Instruments – a runtime performance analysis and debugging tool. You can use Instruments to gather information about your application’s runtime behavior and identify potential problems.
iPhone Simulator – a Mac OS X application that simulates the iPhone technology stack, allowing you to test iPhone applications locally on your Intel–based Macintosh computer.
iPhone Reference Library- the SDK includes the reference documentation for iPhone OS by default and you can download a more complete version of the iPhone Reference Library (including sample code and conceptual documentation) by subscribing to the iPhone OS Library doc set.