Technical Stuff

• NSString (not modifiable)
• NSMutableString (can modify)

 
 //Immutable string , cant modify
 NSString *firstName = @"Pasumarthi";
 //mutable string can modify
 NSMutableString *nameString = [NSMutableString stringWithString:@"Chandu"];
 
 // invalid - trying to make mutable string to non-mutable string 
 //nameString = firstName;
 //invalid - we cant make normal string copy to the mutable.
 //nameString = [firstName copy]; 
 
 // valid as mutablestring is subclass of string
 nameString = [firstName mutableCopy]; 
 
 // valid as mutablestring is subclass of string 
 firstName = nameString;
 //valid as nameString is mutable 
 [nameString appendString:@" Appu"];

 NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"king",@"name",@"9985396338",@"phone", nil];
 // using objectForKey method
 NSLog(@"name is %@", [dict objectForKey:@"name"]);
 // displays null as name1 not found in NSDictionary
 NSLog(@"name1 is %@", [dict objectForKey:@"name1"]);
 // using valueForKey method 
 NSLog(@"phone is %@", [dict valueForKey:@"phone"]);
 // displays null as phone1 not found in NSDictionary
 NSLog(@"phone is %@", [dict valueForKey:@"phone1"]);

// .h file
@interface valueForKeyTest : NSObject
@property NSString *name,*phone;
@end
// .m file
@implementation valueForKeyTest
@synthesize name, phone;
@end
// main.m file
#import "valueForKeyTest.h"
int main(int argc, const char * argv[]) {
 valueForKeyTest *obj = [[valueForKeyTest alloc] init];
 obj.name = @"king";
 obj.phone = @"9985396338";
 
 // valueForKey on accessor methods
 NSLog(@"name is %@", [obj valueForKey:@"name"]);
 NSLog(@"phone is %@", [obj valueForKey:@"phone"]);
 // this will throw valueForUndefinedKey: as name1 is not a property
 NSLog(@"name is %@", [obj valueForKey:@"name1"]);
}

• setValue:forKey:
• valueForKey:
• setValue:forKeyPath:
• valueForKeyPath:
• setValuesForKeysWithDictionary:
• dictionaryWithValuesForKeys:

1. Introduction to iOS
2. Views in iOS
3. ViewControllers
4. StoryBoards
5. Notifications n KeyPadHiding
6. Gestures
7. CustomeGestures
8. ViewHeirarchy, ResponderChain
9. iOSArchitecture
10. DataPersistence
11. SQLite3
12. CoreData
13. XML n JSONParsing
14. Communicating with WebServices
15. AudioVideo Foundation
16. Camera, Accelorometer
17. Memory Crash issues
18. UIPageViewController
19. AutoLayout, iCloud

1. Introductin to ObjectiveC
2. Objects, Classes, Messages in ObjectiveC
3. OOPS concepts in ObjectiveC
4. Properties in ObjectiveC
5. protocols n Categories in ObjectiveC
6. Selectors in ObjectiveC
7. FoundationClasses in ObjectiveC
8. NSString n NSNumber in ObjectiveC
9. NSArray n NSData in ObjectiveC
10. Dictionary, Range, Date in ObjectiveC
11. NSFileManager, NSFileHandle in ObjectiveC
12. Memory Management in ObjectiveC
13. Blocks and GCD

//need to add both in .m file
@interface className (categoryName)
//new methods
@end
@implementation className (categoryName)
//new method definitions
@end

@interface NSObject (display)
-(void) privateDisplay;
@end
@implementation NSObject (display)
-(void) privateDisplay
{
 printf("This is private display\n");
}
@end
//This class is declared in the .h file 
//and inherited from NSObject
@implementation categoryClass
@end

• Used to add the new methods to the exiting class and not variables
• Used to create the private methods in objectiveC
• No keyword is used for declaring category. Only enclosed in braces(see the syntax).
• You can take as many catefories as you want, but they should be unique.

//.h file
@interface className (categoryName)
//new methods
@end
//.m file
@implementation className (categoryName)
//new method definitions
@end

// this is .h file
@interface NSObject (print)
-(void) display;
@end
@interface categoryClass : NSObject
@end
//this is in .m file
@implementation NSObject (print)
-(void) display
{
 NSLog(@"this is display function");
}
@end
@implementation categoryClass
@end
int main()
{
 categoryClass *obj = [[categoryClass alloc] init];
 [obj display];
}

@interface example : NSObject
{
 //compiler dont know where this class located
 forwardDemo *obj;
}
@end
@interface forwardDemo : NSObject
{
 //data
}
@end

//forward declaration
@class forwardDemo;
@interface example : NSObject
{
 forwardDemo *obj;
}
@end
@interface forwardDemo : NSObject
{
 //data
}
@end

@protocol protocolName 
//new methods
@end
//class name and protocol names separated by spaces
@interface className : parentClass <protocolName>
//class methods
@end

// these are in .h file
@protocol player 
-(void) bowling;
-(void) batting;
-(void) fielding;
@end
@interface cricketPlayer : NSObject <player>
-(void) display;
@end
// this is in .m file
@implementation cricketPlayer
-(void) display
{
 NSLog(@"this is display function");
}
-(void)batting
{
 NSLog(@"this is batting");
}
-(void)bowling
{
 NSLog(@"this is bowling");
}
-(void)fielding
{
 NSLog(@"this is fielding");
}
@end
int main(int argc, const char * argv[])
{
 
 cricketPlayer *obj = [[cricketPlayer alloc] init];
 [obj display];
 [obj batting];
 [obj fielding];
 return 0;
}

$gcc `gnustep-config --objc-flags` -L /GNUstep/System/Library/Libraries hello.m -o hello -lgnustep-base -lobjc
sh: gcc: command not found 

$ gcc 'gnustep-config --objc-flags' -L /GNUstep/System/Library/Libraries hello.m -o hello -lgnustep-base -lobjc
gcc.exe: error: gnustep-config --objc-flags: No such file or directory

$ gcc -L /GNUstep/System/Library/Libraries hello.m -o hello -lgnustep-base -lobjc
hello.m:1:34: fatal error: Foundation/Foundation.h: No such file or directory compilation terminated

$ gcc `gnustep-config --objc-flags` -L /GNUstep/System/Library/Libraries hello.m -o hello
C:\Users\CPASUM~1\AppData\Local\Temp\ccifGII6.o:hello.m:(.data+0x0): undefined reference to `__objc_class_name_NSConstantString'
C:\Users\CPASUM~1\AppData\Local\Temp\ccifGII6.o:hello.m:(.data+0x4): undefined reference to `__objc_class_name_NSAutoreleasePool'
AppData\Local\Temp\ccifGII6.o: In function `main':
hello.m:5: undefined reference to `objc_get_class'
hello.m:5: undefined reference to `objc_msg_lookup'
hello.m:5: undefined reference to `objc_msg_lookup'
hello.m:7: undefined reference to `_imp__NSLog'
hello.m:8: undefined reference to `objc_msg_lookup'
ccifGII6.o: In function `_objc_gnu_init':
hello.m:10: undefined reference to `__objc_exec_class'
collect2: ld returned 1 exit status

$ gcc `gnustep-config --objc-flags` hello.m -o hello -lgnustep-base -lobjc
c:/gnustep/bin/../lib/gcc/mingw32/4.6.1/../../../../mingw32/bin/ld.exe: cannot find -lgnustep-base
c:/gnustep/bin/../lib/gcc/mingw32/4.6.1/../../../../mingw32/bin/ld.exe: cannot find -lobjc
collect2: ld returned 1 exit status

• Download the windows installation package which includes three System, Core and Dev exe files from official website.
• Install the packages System, Core and Dev in order.

#import <Foundation/Foundation.h> 
int main (int argc, const char * argv[])
{
 NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
 NSLog (@"Hello World!");
 [pool drain];
 return 0;
}

gcc `gnustep-config --objc-flags` -L /GNUstep/System/Library/Libraries 
hello.m -o hello -lgnustep-base -lobjc

$ ./hello.exe
2012年09月05日 11:57:49.615 hello[1168] Hello World!