This document is a presentation by Pete Goodliffe aimed at programmers with prior iOS experience who want to explore advanced topics in iOS development. It covers using Objective-C effectively, exploiting iOS technologies, various coding idioms, and strategies for creating polished applications, along with case studies of successful apps. The talk also discusses interface design, advanced coding techniques, and audio functionalities within iOS.

1. mobile east
june 2012
advanced iOS
getting your knees wet, rather then your ankles
PETE GOODLIFFE pete@goodliffe.net @petegoodliffe

2. @petegoodliffe
pete@goodliffe.net
goodliffe.blogspot.com
www.goodliffe.net
PE TE G OODL
PROGRAMME
IFFE
R / AUTHOR / COLUMNIST / TEACHER ★ CON SCIENTIOUS CODER

4. me

5. you

6. this

7. iOS is a great platform to work on, and many developers have spend some time looking at
the platform. This talk is aimed at programmers with prior iOS experience who want to get
into iOS in more depth.
This presentation will take you from a basic level of understanding of iOS to look at
advanced topics that will make you apps more polished, better designed and, ideally, more
successful.
Abstract concepts are no use, so in this talk we'll take some existing successful commercial
this
iOS applications as a case study, and see how a selection of iOS technologies and
techniques combine within it.
On the way, we'll see:
‣How to use Objective-C language facilities to their best advantage
‣How to exploit key iOS technologies to save you time and effort
‣iOS development idioms that will improve the quality of your code
‣Creating "universal" iPhone/iPad/retina applications without going mad
‣Successful deployment and testing strategies

8. iOS is a great platform to work on, and many developers have spend some time looking at
the platform. This talk is aimed at programmers with prior iOS experience who want to get
into iOS in more depth.
This presentation will take you from a basic level of understanding of iOS to look at
advanced topics that will make you apps more polished, better designed and, ideally, more
successful.
Abstract concepts are no use, so in this talk we'll take some existing successful commercial
this
iOS applications as a case study, and see how a selection of iOS technologies and
techniques combine within it.
On the way, we'll see:
‣How to use Objective-C language facilities to their best advantage
‣How to exploit key iOS technologies to save you time and effort
‣iOS development idioms that will improve the quality of your code
‣Creating "universal" iPhone/iPad/retina applications without going mad
‣Successful deployment and testing strategies

9. the plan

10. but first...

11. http://www.dilbert.com/strips/comic/2012-04-02/

13. advanced
what does that mean?

14. iPhone objective C
101 cocoa

15. iPhone objective C
101 cocoa
?
iPhone
201

16. topic #1
user interface kung foo
topic #2
”advanced” coding techniques
topic #3
getting animated
topic #4
audio shenanigans
topic #5
ninja tools

17. topic #1
user interface kung foo

18. advice case study code

19. user interface advice
don’t be clever
don’t be cute
be idiomatic

20. standard iOS conventions

21. the “extra” conventions

22. cool stuff

23. cool stuff

25. pull to refresh

26. https://github.com/enormego/EGOTableViewPullRefresh
https://github.com/leah/PullToRefresh
https://github.com/shiki/STableViewController

27. cool stuff

31. (swipey) sidebar

33. https://github.com/Inferis/ViewDeck
http://cocoacontrols.com/platforms/ios/controls/pprevealsideviewcontroller
http://cocoacontrols.com/platforms/ios/controls/hsimagesidebarview

34. ui joy is in the details

39. subtle shadow

40. No Carrier 00:49 Not Charging
UIBarButtonItem Mahjong Score Book UINavigationBar
UIScrollView
UIView
(parent)
Custom UIView

41. No Carrier 00:49 Not Charging
Mahjong Score Book
Gradient

42. No C
arrie
r
19:2
4
100%
✘

43. No C
arrie
r
19:2
4
100%
✘

44. No C
arrie
r
19:2
4
100%
pass touches
through
✔

45. No C
arrie
r
19:2
4
100%

46. No C
arrie
r
19:2
4
100%

47. @interface FadeView : UIView
@end

48. @interface FadeView : UIView
@end
@implementation FadeView
- (void) setUp
{
self.backgroundColor = [UIColor clearColor];
CAGradientLayer *gradientLayer = [[CAGradientLayer alloc] init];
gradientLayer.colors = [NSArray arrayWithObjects:
(id)[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5].CGColor,
(id)[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.0].CGColor,
nil];
gradientLayer.startPoint = CGPointMake(0,0);
gradientLayer.endPoint = CGPointMake(0,1);
gradientLayer.frame = CGRectMake(0,0,self.bounds.size.width, self.bounds.size.height);
[self.layer insertSublayer:gradientLayer atIndex:0];
}
- (id) initWithCoder:(NSCoder *)aDecoder
{
if ((self = [super initWithCoder:aDecoder]))
{
[self setUp];
}
return self;
}
- (id) initWithFrame:(CGRect)frame { /* ... */ }
@end

49. theming toolbars

50. toolbar background
button background
normal pressed
highlighted &
highlighted pressed

51. - (void)viewDidLoad
{
gridView.dataSource = self;
gridView.delegate = self;
[gridView reloadData];
self.navigationItem.title = AppName;
self.navigationItem.rightBarButtonItem = self.editButtonItem;
navigationBar.items = [NSArray arrayWithObject:self.navigationItem];
[self setEditing:NO animated:NO];
if ([[UINavigationBar class] respondsToSelector:@selector(appearance)])
{
UIEdgeInsets insets = {6, 6, 6, 6};
UIImage *image = [[UIImage imageNamed:@"ToolbarBlack"] resizableImageWithCapInsets:insets];
[self.navigationBar setBackgroundImage:image forBarMetrics:UIBarMetricsDefault];
[self styleButton:self.navigationItem.leftBarButtonItem];
[self styleButton:self.navigationItem.rightBarButtonItem];
}
[super viewDidLoad];
}

52. - (void) setEditButtonAppearance
{
if ([[UINavigationBar class] respondsToSelector:@selector(appearance)])
{
UIEdgeInsets insets = {10, 10, 10, 10};
UIImage *navButton = !self.editing
? [[UIImage imageNamed:@"ToolbarBlackButton"] resizableImageWithCapInsets:insets]
: [[UIImage imageNamed:@"ToolbarBlackButtonSelected"] resizableImageWithCapInsets:insets];
UIImage *navButtonPressed = !self.editing
? [[UIImage imageNamed:@"ToolbarBlackButtonPressed"] resizableImageWithCapInsets:insets]
: [[UIImage imageNamed:@"ToolbarBlackButtonSelectedPressed"] resizableImageWithCapInsets:insets];
[self.editButtonItem setBackgroundImage:navButton forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[self.editButtonItem setBackgroundImage:navButtonPressed forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
}
}

53. topic #2
”advanced” coding techniques

54. ♪

55. three
PROBLEMS

56. AVAudioPlayer
✔ Play theme tune
✘ Fade in/out

57. categories
associative references
blocks

58. PROBLEM#1
a nice API

59. categories
(because one interface is never enough)

60. AVAudioPlayer *player = … ;
[player play];
[player stop];

61. AVAudioPlayer *player = … ;
[player play];
[player stop];
[player playWithFadeDuration:1.0];
[player stopWithFadeDuration:1.0];

62. @interface AVAudioPlayer
{
…
}
- (id) initWithContentsOfURL:(NSURL*)url;
- (void) play;
- (void) stop;
@end

63. @interface AVAudioPlayer
{
…
}
- (id) initWithContentsOfURL:(NSURL*)url;
- (void) play;
- (void) stop;
- (void) playWithFadeDuration:(float)secs;
- (void) stopWithFadeDuration:(float)secs;
@end

64. @interface AVAudioPlayer (Fades)
- (void) playWithFadeDuration:(float)secs;
- (void) stopWithFadeDuration:(float)secs;
@end

65. @implementation AVAudioPlayer (Fades)
- (void) playWithFadeDuration:(float)secs
{
// magic happens here
}
- (void) stopWithFadeDuration:(float)secs
{
// clever stuff in here
}
@end

66. AVAudioPlayer *player = … ;
[player play];
[player stop];
[player playWithFadeDuration:1.0];
[player stopWithFadeDuration:1.0];
✔

67. PROBLEM#2
we need some new
instance variables

68. associative references
(a posh name for cheating)

69. static const char volumeLevelKey = ‘Q’;
NSNumber *number = [NSNumber numberWithFloat:1.0];
objc_setAssociatedObject(self,
&volumeLevelKey,
number,
OBJ_ASSOCIATION_RETAIN_NONATOMIC);

70. NSNumber *number =
(NSNumber*)objc_getAssociatedObject(self, &volumeLevelKey);

71. @interface AVAudioPlayer (Fades)
- (void) playWithFadeDuration:(float)secs;
- (void) stopWithFadeDuration:(float)secs;
@property float fadeVolume;
@end

72. - (void) fadeVolume
{
// gibberish in here
}
- (void) setFadeVolume
{
// cobblers in here
}
✔
float fadeVolume = player.fadeVolume;

73. PROBLEM#3
we need to use another
fancy language feature

74. blocks
(because C++ isn’t the only cool language)

75. PROBLEM#3
when a fade has completed,
do “something”

76. typedef void (^FadeCompleteBlock)();

77. typedef void (^FadeCompleteBlock)();
- (void) fadeToVolume:(float)volume
withDuration:(float)secs
andThen:(FadeCompleteBlock)action

78. typedef void (^FadeCompleteBlock)();
- (void) fadeToVolume:(float)volume
withDuration:(float)secs
andThen:(FadeCompleteBlock)action
[player fadeToVolume:0.0
withDuration:1.0
andThen:^{
[player stop];
player.volume = 1.0;
}];

79. http://goodliffe.blogspot.co.uk/2011/04/ios-fading-avaudioplayer.html
https://gitorious.org/audioplayerwithfade/audioplayerwithfade

80. topic #3
getting animated

81. video>>>

83. - (void) documentsViewControllerSelected:(NSString*)file fromRect:(CGRect)from;
{
lastDocumentRect = from;
scoresViewController.filename = file;
[scoresViewController animateAppearingFrom:from afterDelay:0.1];
[window setRootViewController:scoresViewController animated:YES];
}

84. - (void) animateAppearingFrom:(CGRect)rect afterDelay:(NSTimeInterval)delay
{
(void)self.view;
UIImage *image = [mainView drawIntoImage];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[mainView.superview addSubview:imageView];
imageView.frame = rect;
mainView.hidden = YES;
[UIView animateWithDuration:1.0
delay:delay
options:UIViewAnimationOptionAllowUserInteraction
animations:^{
imageView.frame = mainView.frame;
}
completion:^(BOOL finished){
mainView.hidden = NO;
[imageView removeFromSuperview];
}];
}

85. @interface UIView (PGLib)
- (UIImage*) drawIntoImage;
@end
- (UIImage*) drawIntoImage
{
UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.opaque,
[[UIScreen mainScreen] scale]);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}

86. - (void) animateAppearingFrom:(CGRect)rect afterDelay:(NSTimeInterval)delay
{
(void)self.view;
UIImage *image = [mainView drawIntoImage];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[mainView.superview addSubview:imageView];
imageView.frame = rect;
mainView.hidden = YES;
[UIView animateWithDuration:1.0
delay:delay
options:UIViewAnimationOptionAllowUserInteraction
animations:^{
imageView.frame = mainView.frame;
}
completion:^(BOOL finished){
mainView.hidden = NO;
[imageView removeFromSuperview];
}];
}

89. @interface TitlePageView : UIView
{
CAShapeLayer *shapeLayer1;
CAShapeLayer *shapeLayer2;
CAShapeLayer *shapeLayer3;
CALayer *imageLayer;
}
@property (nonatomic, retain) IBOutlet UIButton *playButton;
- (void) startAnimation;
- (void) checkAnimationsRunning;
- (void) stopAnimation;
- (void) setBackgroundImage:(UIImage*)backgroundImage;
@end

90. -(void) startAnimation
{
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
animation.duration = 5.0;
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
animation.repeatCount = 10000;
animation.autoreverses = YES;
animation.fromValue = [NSNumber numberWithDouble:0];
animation.toValue = [NSNumber numberWithDouble:M_PI];
[shapeLayer1 addAnimation:animation forKey:@"animatePath"];
animation.duration = 8.0;
[shapeLayer2 addAnimation:animation forKey:@"animatePath"];
animation.duration = 13.0;
[shapeLayer3 addAnimation:animation forKey:@"animatePath"];
}
-(void) stopAnimation
{
[shapeLayer1 removeAllAnimations];
[shapeLayer2 removeAllAnimations];
[shapeLayer3 removeAllAnimations];
}

91. topic #4
audio shenanigans

92. you have a phone
it makes a noise
how do you do that?

93. CoreAudio
Audio
} {
Services
OpenAL Headphones
AVAudioPlayer Speaker
Your code Audio
Session
Audio USB
Queue
Audio
Unit Bluetooth
Audio File
Services

94. Audio Session Services
} {
OpenAL Phones
AVAudioPlayer
Speaker
Code Session
Queue USB
Unit BT
Phone Call
Describe type
App Doing my
of audio use & INTERRUPTION! Resume
starts audio thing
start session
Other apps

95. Audio Services Services
} {
OpenAL Phones
AVAudioPlayer
Speaker
Code Session
Queue USB
Unit BT
@interface Sounds : NSObject
{
SystemSoundID lock;
}
- (void) lock;
@end
@implementation Sounds
- (id)init
{
if ((self = [super init]))
{
NSBundle *bundle = [NSBundle mainBundle];
NSURL *lockUrl = [bundle URLForResource:@"Noise" withExtension:@"wav"];
AudioServicesCreateSystemSoundID((__bridge CFURLRef)lockUrl, &lock);
}
return self;
}
- (void) lock
{
AudioServicesPlayAlertSound(lock);
}
@end

96. OpenAL Services
} {
OpenAL Phones
AVAudioPlayer
Speaker
Code Session
Queue USB
Unit BT
OpenAL is a cross-platform 3D audio API appropriate for use with
gaming applications and many other types of audio applications.
The library models a collection of audio sources moving in a 3D
space that are heard by a single listener somewhere in that space.
The basic OpenAL objects are a Listener, a Source, and a Buffer. There
can be a large number of Buffers, which contain audio data. Each
buffer can be attached to one or more Sources, which represent
points in 3D space which are emitting audio. There is always one
Listener object (per audio context), which represents the position
where the sources are heard -- rendering is done from the
perspective of the Listener.

97. AVAudioPlayer Services
} {
OpenAL Phones
AVAudioPlayer
Speaker
Code Session
Queue USB
Unit BT
“Apple recommends that you use
this class for audio playback unless
”
you are playing audio captured
from a network stream or require
very low I/O latency.

98. AVAudioPlayer Services
} {
OpenAL Phones
AVAudioPlayer
Speaker
Code Session
Queue USB
Unit BT
play single sound
(memory or file)
seek
control level
read level

99. Services
} {
OpenAL Phones
AVAudioPlayer
Speaker
Code Session
Queue USB
Unit BT
Audio Audio
Queue Unit
low latency lowest latency
plug-in
architecture
dealing with plain old PCM audio data

100. topic #5
ninja tools

101. #pragma mark
. . .
}
afterDelay:0.5];
}
return imported >= 0;
}
//==============================================================================
#pragma mark - IBActions
- (IBAction)add:(id)sender
{
[self hideTipView];
unsigned index = [documents addNewGame];
[gridView
. . .
. . .
[popup presentFromRect:popupRect inView:gridView.superview
withText:view.name
withObject:[NSNumber numberWithUnsignedInt:[gridView indexForCell:cell]]];
}
#pragma mark UIActionSheetDelegate
- (void) actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
sheet = 0;
if (buttonIndex != 0) return;
. . .

102. TestFlight

104. (don’t reinvent)

105. http://cocoacontrols.com/
http://www.stackoverflow.com/
http://www.github.com/

106. QA
★★★
&
★★★
Pete Goodliffe @petegoodliffe pete@goodliffe.net

107. @petegoodliffe
pete@goodliffe.net
goodliffe.blogspot.com
www.goodliffe.net

108. BUMPH DULL, but important ★
THIS DOCUMENT WAS CREATED BY PETE GOODLIFFE
IT IS COPYRIGHT // © 2012 PETE GOODLIFFE
>> ALL RIGHTS RESERVED
>> ALL THOUGHTS ARE OWNED
>> PHOTOS AND IMAGES ARE MOSTLY
SOURCED FROM THE WEB
THANK YOU FOR READING // I HOPE IT WAS USEFUL
Version 1.0 2012-08-14