iOS DevelopmentMd. Shakil AhmedSoftware EngineerAstha it research & consultancy ltd.Dhaka, Bangladesh16th October 2011
IntroductionTopic Focus:- What is iOS & iOS Development?- iOS Dvelopment tools- Creating a new iOS application.- Getting Familiar with Xcode and iOS SDK- Delegate- Objective C- Memory Management- Crash Reports- iPhone frameworks
What is iOS & iOS Development?• iOS stands for iPhone Operating System• iOS made for iPhone, iPod Touch & iPad• iOS development is developing applications for iOS Devices.
iOS ApplicationThere is three ways to do mobile applications• Mobile Web Interface• Develop by Flash• Develop by the native platform
Flash• Can be used if the application is all about interface• currently flash can be used to act like real application, it has access to camera, GPS... Etc• Performance in not good like the native platform.
Native Applications• You can do what ever you want to do, except what the framework doesn’t allow you to do.
Create New Application1. Open Xcode.2. Select File→New Project.3. In the dialog that opens, select iPhone OS, then View-Based Application and click Choose.4. Name the project “HelloWorld” and click Save.5. At this point, you can build and run (click the Build and Go icon in the toolbar). The HelloWorld application shows only a blank gray screen when run in the Simulator.
nib---file?• Interface Builder is used for creating Uis• The interface is stored in a file .n/xib – .nib = Next Interface Builder – .xib = new version (Interface Builder 3) of nib• The xib file is xml!
Design Pattern: Delegate• Xcode project template has provided UIApplicaIonDelegate for you• Can implement: - applicationDidFinishLaunching - applicationWillTerminate – applicationDidReceiveMemoryWarning• One object sends periodically messages to another object specified as its delegate
Objective C• You can consider it Extension for C language• ObjC add more dynamicity to C Language• Single inheritance from super class and protocols is used as interfaces• Totally new syntax but still can use C with it.
Objective CNew concepts – Class definition – Protocol implementation – Class messages – Many more …
Classes and Objects• Classes declare the state and behavior• State (class data) is instance variables• Behavior is methods
Class and instance methods• Instances responds to “Instance methods” 1. -(id)init; 2. -(char*)getName;• Class responds to “Static methods” 1. +(id)alloc; 2. +(char*)getClassName;
Message syntax (calling methods)• Function calling in Objective C called message, this is to give more dynamicity to the language, some times if the method is not implemented the calling result will be nil = null – [objectOfClass functionName]; – [objectOfClass functionName:Arg1];• Calling staic method – [Class functionName]; – [Class functionName:Arg1];
Objective C• Dot Syntax – It is only working in Objective C 2.0 – It is only used for properties of object• Dynamic Casting – Using type “id” , id is pointer to void “C Style void*” – id object = [Class new];• Static casting – Class* object = [Class new];
Objective C• nil is equivalents to null• Objective C Class has no operators overloading• Objective C Class has no constructors or destructors• Boolean type is, BOOL – YES is TRUE – NO is FALSE
Memory ManagementRules :You only release or autorelease objects you own.• If you own the object by alloc, copy or retain, you have to release or autorelease• If the object is not owned by you, don’t call release or autorelease