iPhone development in Objective-C

Issues when installing on device:

Check that iPhone Profile has been installed (in the Organizer, Window menu -> Organizer).

Project properties (Project icon -> Get Info): Check "Code Signing Identity", that the right iPhone Profile is selected.

Info.plist: "Bundle identifier", should be: com.adifferentgame.${PRODUCT_NAME:identifier}

"Base SDK Missing" Check targets -> info

Xcode Templates

(in Xcode.app): /Library/Developer/Xcode/Templates/

Simulator

// Check of running on Simulator #if !(TARGET_IPHONE_SIMULATOR) // Device #else // Simulator #endif

Managed Object Accessor Methods

//.h @property (nonatomic, retain) GameCharacter* selectedCharacter; //.m @synthesize selectedCharacter;

assign/retain/copy // "retain" will release old object readonly/readwrite nonatomic // for object types strong // replacement for the retain attribute, as part of Objective-C Automated Reference Counting (ARC). In non-ARC code it's just a synonym for retain. getter=newName setter=setterName

Remove ARC for files

-fno-objc-arc

Program Flow, Loops etc

if (touchPoint.y < viewController.view.bounds.size.height * 1.0/3.0) { NSLog(@"Top"); } else if (touchPoint.y > viewController.view.bounds.size.height * 2.0/3.0) { NSLog(@"Bottom"); } else { NSLog(@"Middle"); }

switch (expression) { case match1: { statements break; } case match2: statements break; default: statements break; }

int i = 10; do { i--; } while (i > 0)

while ( myCount < 100 ) { myCount++; }

Try and Catch

@try { a = [test characterAtIndex:index]; } @catch (NSException *exception) { NSLog(@"%@", exception.reason); } @finally { NSLog(@"Char at index %d cannot be found", index); NSLog(@"Max index is: %d", [test length]-1); }

Nil & Null

nil (all lower-case) is a null pointer to an Objective-C object. Nil (capitalized) is a null pointer to an Objective-C class. NULL (all caps) is a null pointer to anything else.

if (title == (id)[NSNull null] || title.length == 0 ) title = @"Something";

// This doesn't work for null objects, only nil objects if (!myobject)

bool & BOOL

BOOL = Objective-C, bool = C

Numbers

int myInt = (int) myFloat; float myFloat = (float) myInt;

// Naive Min/Max #define MIN(a,b) ((a) < (b) ? (a) : (b)) #define MAX(a,b) ((a) > (b) ? (a) : (b))

// Get random value between 0 and 99 int x = (arc4random() % 100); // Get random number between 500 and 1000 int y = 500 + (arc4random() % 501);

__block int rowNr = 0; // In loop: rowNr += 1;

Strings

length = [myString length];

[NSString stringWithFormat:@"%@, %@, %@", three, two, one];

if ([string hasSuffix:@"y"]) NSString *s = @"avant"; s = [s stringByAppendingString:@" - après"]; // or [NSString stringWithFormat:@"%@/%@/%@", three, two, one];

NSString *lower = [myString lowercaseString];

if ([returnedString isEqualToString:@"thisString"]) NSLog(@"Equal"); else NSLog(@"Not Equal");

// Substrings

str = [str substringToIndex: MIN(15, [str length])]; [@"abc xyz http://www.abc.com aaa bbb ccc" substringWithRange:NSMakeRange(8, 18)]

// Split: NSString *string = @"oop:ack:bork:greeble:ponies"; NSArray *array = [string componentsSeparatedByString: @":"]; // Join NSString *string2 = [array componentsJoinedByString: @":"];

// Search

// NSRange has location, length NSRange searchRange = [bigString rangeOfString:stringToFind options:NSCaseInsensitiveSearch]; if (searchRange.location != NSNotFound) { // Found something! }

// Backwards/reverse search [@"abc def ghi abc def ghi" rangeOfString:@"abc" options:NSBackwardsSearch];

// Search & Replace tempString = [tempString stringByReplacingOccurrencesOfString:@"oldText" withString:@"newText"];

NSRange endRange = [original rangeOfString:@"End."]; NSRange searchRange = NSMakeRange(0, endRange.location); NSString *noBrackets = [original stringByReplacingOccurrencesOfString:@"[" withString:@"" options:0 range:searchRange];

Arrays

strings = [NSArray array];

array = [[NSMutableArray alloc] initWithCapacity:4]; array.count;

NSArray *array = [NSArray arrayWithObjects: @"NameRowA",@"NameRowB",@"NameRowC", nil];

obj = [array objectAtIndex:2];

insertObject:atIndex: removeObjectAtIndex: addObject: // [array addObject:@"Ett"]; removeLastObject replaceObjectAtIndex:withObject:

__block int rowNr = 0; for (NSObject* o in array1) { rowNr += 1; NSLog(@"%@", o); }

Hashtables/Dictionaries

NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init]; [dictionary setObject:anObj forKey:@"foo"]; [dictionary objectForKey:@"foo"]; [dictionary removeObjectForKey:@"foo"]; [dictionary release];

Date & Time

// Get current date as string NSDateFormatter dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; NSString dateString = [dateFormatter stringFromDate:[NSDate date]]; [dateFormatter release]; // Remove if ARC. You might want to keep the formatter if you're doing this a lot.

// Rails // 2012-07-25T12:32:28+02:00 -> remove colons first

// Date to String NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; NSString *dateString=[dateFormatter stringFromDate:[NSDate date]];

// String to Date NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; NSDate *myDate =[dateFormatter dateFromString:dateString];

// Rails date NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZZZ"]; NSLog(@"DATE FORMAT:%@", [dateFormatter dateFromString:@"2008-12-29T00:27:42-0800"]);

// Time Zones NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];

Class check

[myObject isKindOfClass:[NSString class]]

if (self == (MyClass*)0x5633b0) NSLog(@"Allocated object at address 0x5633b0"); // put a breakpoint on this line

#import <objc/runtime.h>

const char* className = class_getName([yourObject class]); NSLog(@"Object is of class: %s", className);

Methods

min:(int)a :(int)b; ... [Utils min:a :b]

Super Class

(void)viewDidLoad { [super viewDidLoad]; }

Class Properties & Methods

static NSString * const kAFIncrementalStoreExampleAPIBaseURLString = @"http://localhost:5000";

// Header

(SongAPIClient *)sharedClient;

// Implementation

(SongAPIClient *)sharedClient { static SongAPIClient *_sharedClient = nil; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ _sharedClient = [[self alloc] initWithBaseURL:[NSURL URLWithString:kAFIncrementalStoreExampleAPIBaseURLString]]; }); return _sharedClient; }

Constructors

(id) init { self = [super init]; if (self != nil) { // initializations go here. } return self; }

Protocols

@protocol NewsViewController //@optional

(void) newDataAvailable:(NSArray*)data; @end

Exceptions

[NSException raise:@"Invalid foo value" format:@"foo of %d is invalid", foo];

IBOutlet and IBAction

MyViewController.h

@interface FirstViewController : UIViewController

@property (strong, nonatomic) NSMutableArray* allExistingPlayersData; @property (nonatomic, retain) IBOutlet UITextField* searchTextField; @property (nonatomic, retain) IBOutlet UIButton* searchButton; @property (nonatomic, retain) IBOutlet UILabel *statusLabel; @property (weak, nonatomic) IBOutlet UIButton *startButton;

(IBAction) doActionEvent:(id)sender;

@end

MyViewController.m

@synthesize searchTextField; @synthesize searchButton;

(IBAction) doActionEvent { // Do something }

UI elements - UIView

targetView.hidden = YES;

urlField.text = @"Hello!";

[CLName setStringValue:name];

// Position and Size viewController.view.bounds.position.x viewController.view.bounds.size.height

Selectors

[newSprite runAction:[CCSequence actions: action, [CCCallFuncN actionWithTarget:self selector:@selector(myCustomMethod:)], nil]];

-(void)myCustomMethod: (id)node { }

runAction:[CCSequence actions: action, [CCCallFuncN actionWithTarget:self selector:@selector(removeRing:)], nil]

Events

Timers

updateTimer = [NSTimer scheduledTimerWithTimeInterval:1.5 target:self selector:@selector(onTimerUpdate:) userInfo:nil repeats:YES];

(void)onTimerUpdate:(NSTimer*)timer { }

[updateTimer invalidate]; updateTimer = nil;

Animations

// Simple [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:2]; [view1 setAlpha:0.00]; [UIView commitAnimations];

// Linked

(void) fadeOut:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:2]; [UIView setAnimationDelegate:self]; if(animationRunning){ [UIView setAnimationDidStopSelector:@selector(fadeIn:finished:context:) ]; } [view1 setAlpha:0.00]; [UIView commitAnimations]; }
(void) fadeIn:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:2]; [UIView setAnimationDelegate:self]; if(animationRunning){ [UIView setAnimationDidStopSelector:@selector(fadeOut:finished:context:) ]; } [view1 setAlpha:1.00]; [UIView commitAnimations]; }

[self fadeOut:nil finished:nil context:nil];

Images - UIImage

[countDownImage setImage:[UIImage imageNamed:@"firstLaunch.png"]];

CAF Sound Files

afconvert -f caff -d ima4 in.wav out.caf //afconvert -f caff -d LEI16@44100 -c 1 in.wav out.caf

User Preferences/Settings

// Read NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults]; NSString *userName = [prefs stringForKey:@"userName"];

// Write NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults]; [prefs setObject:userName forKey:@"userName"]; [prefs synchronize];

NSInteger myInt = [prefs integerForKey:@"integerKey"]; float myFloat = [prefs floatForKey:@"floatKey"];

[prefs setInteger:42 forKey:@"integerKey"]; [prefs setDouble:3.1415 forKey:@"doubleKey"]; [prefs setFloat:1.2345678 forKey:@"floatKey"];

Memory management: Alloc, Release, Dealloc

alloc <-> release For every 'alloc', a 'release' - 'dealloc' happens automatically. http://stackoverflow.com/questions/3342129/iphone-release-dealloc

Memory leaks happens when a code does a “new”, “malloc”, or “alloc”, but never does a corresponding “delete”, “free” or “release” respectively. http://mobileorchard.com/find-iphone-memory-leaks-a-leaks-tool-tutorial/

create object (alloc, new, copy): retain count = 1 retain: retain count +1 release: retain count -1 autorelease: retain count -1 at some stage in the future retain count = 0 --> deallocated

Pragma Marks

#pragma mark CCGLView - Mouse events

Debugging

http://www.cocoadev.com/index.pl?DebuggingTechniques

NSLog(@"Current object: %@", self);

Debugging spurious retains/releases in 3 easy steps

http://stackoverflow.com/questions/3791302/why-is-my-objective-c-object-being-deallocated

Override -retain, -release, and -autorelease for the class you are interested in. Make them log a message (NSLog(@"%@ %s", self, sel_getName(_cmd))) and super-call.
Breakpoint all these methods (at the super-call, i.e. after the log message so you know which object it is). Edit the breakpoint; add the command "bt" and check the auto-continue box (or just use two commands "bt", "continue").
Clear the log. Run the app. Print out the log. Stick it to a whiteboard. Draw some arrows until you find the spurious release/autorelease.

(id)retain { NSLog(@"%@ %s", self, sel_getName(_cmd)); return [super retain]; }
(oneway void)release { NSLog(@"%@ %s", self, sel_getName(_cmd)); return [super release]; }
(id)autorelease { NSLog(@"%@ %s", self, sel_getName(_cmd)); return [super autorelease]; }

GDB Debugging

print-object anObj print-object [anObj description] print-object [nsStr stringByAppendingString:@" yes"] print (int) [@"John Galt" length] print (char *) [nsStr UTF8String]

other commands: bt - backtrace call [exp]: Calls the function set [var] = [exp] whatis [variable]: print details about variable help info symbol 0x5633b0 info malloc-history 0x5633b0 More: http://www.freebsd.org/doc/en/books/developers-handbook/debugging.html

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iPhone development in Objective-C.md

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