Iphone Development (I) Basic knowledge

What you need to know before developing the iPhone SDK:

I. iphone features:

1. iphone screen resolution: 640*960;

2. Garbage collection supported in objective-c is not supported in iphone development;

3. In principle, the iphone does not support backend services. Although Apple provides a set of multi-task APIs, they are only used in a few cases and are not necessarily reliable: the smoothness of programs running on the current screen is greater than that of all programs;

4. All applications run in an independent File System (sandbox). If you want to call system resources, you need APIs;

5. The simulator cannot be installed with officially released programs;

6. The iphone system is called iOS;

7. The default iphone application icon is icon.png and the size is 57*57.

Ii. Technical hierarchy of iOS:


 

The top Cocoa Touch layer includes multiple frameworks: UIKit, MapKit, GameKit, Message UI/Address BookUI, iAd

Media is a multimedia layer, including: AV foundation Framework, CoreAudio, CoreGraphics, CoreText, Image I/O, Media Player, OpenGL ES, Quartz Core

The framework provided in the Core Services service layer is generally used for some basic operations, including: Address Book, CFNetwork, Core Data, Core Foundation, Foundation, Event Kit, Core Location, Core Motion, quick Look, Store Kit, System Configuration

At the bottom is the core system layer, which is basically not operated on.

I can't remember the above frameworks, but we need to understand three frameworks: CoreGraphics, Foundation, and UIKit. among them, the CG framework is used to process graphics and images. In the Foundation framework, there are mainly some classes and methods in Objective-c. The UIKit is the most important. We have a framework that is the most often used for programming, basically, Cocoa Touch is based on UIKit. These three frameworks are automatically generated when you create a project in Xcode. The importance of these three frameworks is obvious. Generally, applications can use these three frameworks.

3. File layout in Xcode (version 4.3)
Create a new project named "First Application". The following layout is displayed.



 

This is the format after Xcode's automatic layout. It is not in contrast to the file format on the disk. It is just for convenience of editing. We can see that there are four common frameworks attached. The main method is the program portal, the AppDelegate class is the delegate class, the ViewController class is the control class, and the event responses are all here. ViewController. xib is a layout file, which is similar to the xml function in android development. It used to be a nib suffix, so we can often see the nib file. "The first application-Info. plist" is the application configuration file, which contains various attributes of the app. You can modify icons and perform other operations. In summary, we can find that the iphone development model is a typical MVC model. In addition, we can drag and drop these files, not necessarily in this fixed typographical format, or even create folders for management. Now, let's get to know more about this. Next time, we will use helloworld to study the running track and lifecycle of iphone applications.

Keywords: iphone development, Iphone Foundation, iphone Development Foundation, iphone application framework, iphone application layout, iphone application characteristics.

 

From the holydancer Column