iPhone Seminar Part 2

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The PPTs from one of the event of iWillStudy.com - a leading start-up in the education space in India. This PPT is being used at an event where they taught iPhone programming and applications …

The PPTs from one of the event of iWillStudy.com - a leading start-up in the education space in India. This PPT is being used at an event where they taught iPhone programming and applications development.

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  • 1. SAY HELLO TO iPhone ProgrammingiWillStudy.com - Gargi Das, iPhone Geek !
  • 2. Development Tools Copyright xCode Interface Builder Instruments iPhone simulator
  • 3. xCode IDE Copyright
  • 4. Interface Builder Copyright
  • 5. iOS Simulator Copyright
  • 6. Instruments Copyright
  • 7. Objective C Copyright Objective C is simply a super set of c. One can easily compile c code using Objective C compiler and alternatively the developer can also put c code any where in the objective c code. Syntax of all non Object Oriented operations are similar as C. Rest syntax is taken from Smalltalk. Everything Happens At Runtime( Every error is just a warning).
  • 8. Objective C Terms Copyright Messages Interface, Implementations & Instantiation Protocols Memory Management
  • 9. Message Passing Copyright C++ Way(obj->methodName(Parameter)) Objective C Way([obj methodName:Parameter]) Target of the message is always resolved at runtime. In Objective-C one does not call a method; one sends a message
  • 10. Interfaces 1 Copyright@interface classname : superclassname{ // instance variables The interface of a class is} usually defined in a header file+ classMethod1;+ (return_type)classMethod2;+ (return_type)classMethod3:(param1_type)param1_varName;- (return_type)instanceMethod1:(param1_type)param1_varNameandOtherParameter:(param2_type)param2_varName;-(return_type)instanceMethod2WithParameter:(param1_type)param1_varName andOtherParameter:(param2_type)param2_varName;@end
  • 11. Interfaces Copyrightclass classname : public superclassname{ public: // instance variables The code above is roughly equivalent to the following C++ // Class (static) functions interface static void * classMethod1(); static return_type classMethod2(); static return_type classMethod3(param1_type param1_varName); // Instance (member) functionsreturn_type instanceMethod1(param1_type param1_varName, param2_typeparam2_varName);return_type instanceMethod2WithParameter(param1_type param1_varName,param2_type param2_varName=default);};
  • 12. Implementation CopyrightImplementation (method) files normally have the file extension .m, which originally signified "messages“@implementationclassname+classMethod {// implementation} The interface only declares-instanceMethod { the class interface and not the// implementation methods themselves: the actual} code is written in the@end implementation file
  • 13. Instantiation Copyright Object is instantiated by first allocating the memory for a new object and then initializing. Instantiation with default initializer  NSArray *array = [[NSArray alloc] init]; Or you can use  NSArray *array = [NSArray new]; Instantiation with Custom initializer  NSArray *array = [[NSArray alloc] initWithObjects:@"String1",@"String2",nil];
  • 14. Protocol Copyright Polymorphism in c++. Two Types:  Formal Protocol.  Informal Protocol.  Delegates are example of Informal Protocol.  Interface Classes from c++ are example of Formal Protocol. A formal protocol is similar to An informal protocol is a list of an interface in Java or C#. It is a list methods that a class can opt to of methods that any class can implement. declare itself to implement.
  • 15. Managing Memory Copyright Basic Fundamentals Memory Management Rules Passing objects between Methods Working with Properties Deallocating Object Leaks and Static Analyzer Rule #1 – If you create an object using alloc or copy, you need to free that object. Rule #2 – If you didn’t create an object directly, don’t attempt to release the memory for the object.
  • 16. Managing Memory:Fundamentals Copyright What is memory management?  “Managing the resources efficiently and effectively”. Memory management in other languages.  In C,C++ we have malloc, calloc and free.  In other object oriented languages we have Garbage Collectors. So what is there in Objective C?  “Retain Count”  No need to worry about Primitive Data Types
  • 17. Memory Management:Rules Copyright You own any object you create.  You “create” an object using a method whose name begins with “alloc” or “new” or contains “copy”.  e.g. Alloc MyClass *myObject = [[MyClass alloc] init]; // do your work with myObject [myObject release] ;  e.g. Copy
  • 18. Memory Management:Rules Copyright You can take ownership of an object using retain method. NSArray* componentArray = [[self cellforIndexPath:indexPath]retain]; /* */ [componentArray release]; You must relinquish ownership of objects you own when you’re finished with them.  You relinquish ownership of an object by sending it a release message or an autorelease message. You must not relinquish ownership of an object you do not own. NSString* myString = [NSString stringWithFormat:@"%@",[myItem currentItem]]; [myString release]; // this is absolutely wrong
  • 19. Memory Management:Passing Objects between Methods Copyright This is wrong– (NSArray *)sprockets {NSArray *array = [[NSArray alloc] initWithObjects:mainSprocket, auxiliarySprocket, nil];return array;} This is also wrong – (NSArray *)sprockets { NSArray *array = [[NSArray alloc] initWithObjects:mainSprocket, auxiliarySprocket,nil]; [array release]; return array; // array is invalid here }
  • 20. Memory Management: Passing Objects between Methods Copyright  The right way – (NSArray *)sprockets { NSArray *array = [NSArray arrayWithObjects:mainSprocket, auxiliarySprocket, nil]; return array; }  You can also do this– (NSArray *)sprockets {NSArray *array = [[NSArray alloc] initWithObjects:mainSprocket, auxiliarySprocket, nil];return [array autorelease];}
  • 21. Working with Properties Copyright Property Declaration @interface myClass:NSObject { float aValue; } @property float aValue; @end @property float aValue is equal to : float aValue; setValue(float iValue);
  • 22. Working with Properties Copyright Assign  No need to worry about Memory here. Just a pointer to the object is assigned to variable. Self.parentController = controller Copy self.controlArray = [someOtherArray copy]; //retain count controlArray = 1, someOtherArray = 1 [someOtherArray release]; //we need to release someOtherArray
  • 23. Deallocating Objects Copyright When object’s retain count drops to 0, its memory is reclaimed in Cocoa terminology it is “freed” or “deallocated.” Os does this calling the “dealloc” method. e.g. -(void)dealloc { [myObject1 release]; [someContainer release]; [super release]; } You should never invoke another object’s dealloc method directly.
  • 24. Installing App in iPhone Copyright
  • 25. Installing App in iPhone Copyright First Thing You need a Apple Developer Account. Once you have a account you will have a developer portal. Using the portal you can generate provisioning files for your device (which are nothing but certificates). And you need to add that certificate information to your application and then install that in the device.
  • 26. UI Controls Copyright Button – UIButton TextField – UITextField Image – UIImage&UIImageView Table/Lists – UITableView View – UIView View Controller – UIViewController Navigation -- UINavigationController
  • 27. Demo App 1 Copyright Hello World
  • 28. Demo App 2 Copyright Image viewer
  • 29. Worldis Yours! Play it  Copyright
  • 30. Be in Touch Copyright Event PPTs & Study Material: http://iwillstudy.com/event/seminar-on-Learn-iPhone- Programming-at-Rajkot-29 Join us on Facebook: www.facebook.com/iwillstudy Ask Questions: www.iwillstudy.com/forum Our Blog: http://blog.iwillstudy.com Email us: tech@iwillstudy.com