Ios development


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Ios development

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Ios development

  1. 1. iOS DevelopmentMd. Shakil AhmedSoftware EngineerAstha it research & consultancy ltd.Dhaka, Bangladesh16th October 2011
  2. 2. 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
  3. 3. 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.
  4. 4. iOS ApplicationThere is three ways to do mobile applications• Mobile Web Interface• Develop by Flash• Develop by the native platform
  5. 5. Mobile Web Applications• This application is mostly connected, so most of the time user can’t handle it without internet or cached history• Javascript provides reach function to access some hardware like GPS and other devices specific hardware• Developer doesn’t have much authority over the device, tied by the browser.
  6. 6. 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.
  7. 7. Native Applications• You can do what ever you want to do, except what the framework doesn’t allow you to do.
  8. 8. Smartphone OS Market Share, Q4 2010
  9. 9. Needed to develop for iPhone• Knowledge of Objective C• Mac OS X Intel based machine• iPhone Development tools• iPhone or iPod touch
  10. 10. iPhone Development tools• Xcode
  11. 11. 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.
  12. 12. Create New Application
  13. 13. Xcode
  14. 14. Xcode• Compiled Code -> yours and frameworks• Nib – files: UI--- elements• Resources: images, sounds.• Info.plist – file: app configuraIon
  15. 15. info.plist
  16. 16. Info.plist in Xcode
  17. 17. 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!
  18. 18. nib---file
  19. 19. Nib – files in Interface Builder
  20. 20. icons and images
  21. 21. Life Cycle
  22. 22. 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
  23. 23. Delegate#import <UIKit/UIKit.h>@interface HelloWorldAppDelegate : NSObject <UIApplicationDelegate> {UIWindow *window;UITextField *mytextfield;}@property (nonatomic, retain) IBOutlet UIWindow *window;@property (nonatomic, retain) IBOutlet UITextField *mytextfield;- (IBAction) userClicked: (id) sender;@end
  24. 24. Delegate• nonatomic - single threaded application• retain - memory management• IBOutlet - variables to attach to Interface Builder objects• IBAction - methods to attach to Interface Builder actions
  25. 25. In Interface Builder
  26. 26. Delegate classes implementation#import "HelloWorldAppDelegate.h"@implementation HelloWorldAppDelegate@synthesize window;@synthesize mytextfield;- (IBAction) userClicked: (id) sender{NSString* text = [mytextfield text];UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Hello“ message:text delegate:nil cancelButtonTitle:@"Ok“ otherButtonTitles:nil];[alert show];[alert release];}
  27. 27. Delegate classes implementation- (void)applicationDidFinishLaunching:(UIApplication *)application {// Override point for customization after application launch[window makeKeyAndVisible];}- (void)dealloc {[window release];[super dealloc];}@end
  28. 28. Result
  29. 29. 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.
  30. 30. Objective CNew concepts – Class definition – Protocol implementation – Class messages – Many more …
  31. 31. Classes and Objects• Classes declare the state and behavior• State (class data) is instance variables• Behavior is methods
  32. 32. 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;
  33. 33. 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];
  34. 34. 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];
  35. 35. 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
  36. 36. 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
  37. 37. Memory Management
  38. 38. Memory ManagementLocal Variable• Always release or autorelease in the same scope
  39. 39. Crash Reports
  40. 40. Crash Types• EXC_BAD_ACCESS (SIGBUS or SIGSEGV)• EXC_CRASH (SIGABRT)• Low Memory• 00000020
  41. 41. iPhone frameworks• Foundation MapKit• UIKit IOKit• CoreGrphics MediaPlayer• CFNetwork AddressBook• CoreLocation MobileCoreSerivces• CoreData• ExternalAccessory OpenGL• GameKit Security StoreKit And many more
  42. 42. CoreData
  43. 43. Core Location & MapKit
  44. 44. Multitasking• Available in iOS 4.
  45. 45. iPhone Development• It is true that Objective C is not as strong as any other language but the huge coverage of frameworks that is provided by Apple makes it Ok to use such SDK.
  46. 46. Thanks!