Advanced iOS

mobile east
june 2012

advanced iOS
getting your knees wet, rather then your ankles

PETE GOODLIFFE pete@goodliffe.net @petegoodliffe

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

PE TE G OODL
PROGRAMME
IFFE
R / AUTHOR / COLUMNIST / TEACHER ★ CON SCIENTIOUS CODER

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

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

advanced
what does that mean?

iPhone objective C

101 cocoa

iPhone objective C

101 cocoa

?
iPhone

201

topic #1
user interface kung foo

topic #2
”advanced” coding techniques

topic #3
getting animated

topic #4
audio shenanigans

topic #5
ninja tools

topic #1
user interface kung foo

user interface advice

don’t be clever
don’t be cute
be idiomatic

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

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

http://cocoacontrols.com/platforms/ios/controls/hsimagesidebarview

No Carrier 00:49 Not Charging

UIBarButtonItem Mahjong Score Book UINavigationBar

UIScrollView

UIView
(parent)

Custom UIView

No Carrier 00:49 Not Charging

Mahjong Score Book
Gradient

No C
arrie
r
19:2
4

100%

✘

No C
arrie
r
19:2
4

100%

pass touches
through

✔

No C
arrie
r
19:2
4

100%

@interface FadeView : UIView
@end

@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

toolbar background

button background

normal pressed

highlighted &
highlighted pressed

- (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];
}

- (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];
}

}

topic #2
”advanced” coding techniques

AVAudioPlayer

✔ Play theme tune
✘ Fade in/out

categories
associative references
blocks

categories
(because one interface is never enough)

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

[player play];
[player stop];

[player playWithFadeDuration:1.0];
[player stopWithFadeDuration:1.0];

@interface AVAudioPlayer
{
…
}

- (id) initWithContentsOfURL:(NSURL*)url;

- (void) play;
- (void) stop;

@end

@interface AVAudioPlayer
{
…
}

- (id) initWithContentsOfURL:(NSURL*)url;

- (void) play;
- (void) stop;
- (void) playWithFadeDuration:(float)secs;
- (void) stopWithFadeDuration:(float)secs;

@end

@interface AVAudioPlayer (Fades)


@end

@implementation AVAudioPlayer (Fades)

- (void) playWithFadeDuration:(float)secs
{
// magic happens here
}

- (void) stopWithFadeDuration:(float)secs
{
// clever stuff in here
}

@end

[player play];
[player stop];

[player playWithFadeDuration:1.0];
[player stopWithFadeDuration:1.0];

✔

PROBLEM#2

we need some new
instance variables

associative references
(a posh name for cheating)

static const char volumeLevelKey = ‘Q’;
NSNumber *number = [NSNumber numberWithFloat:1.0];

objc_setAssociatedObject(self,
&volumeLevelKey,
number,
OBJ_ASSOCIATION_RETAIN_NONATOMIC);

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

@interface AVAudioPlayer (Fades)


@property float fadeVolume;

@end

- (void) fadeVolume
{
// gibberish in here
}

- (void) setFadeVolume
{
// cobblers in here
}

✔
float fadeVolume = player.fadeVolume;

PROBLEM#3

we need to use another
fancy language feature

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

PROBLEM#3

when a fade has completed,
do “something”

typedef void (^FadeCompleteBlock)();


- (void) fadeToVolume:(float)volume
withDuration:(float)secs
andThen:(FadeCompleteBlock)action


- (void) fadeToVolume:(float)volume
withDuration:(float)secs
andThen:(FadeCompleteBlock)action

[player fadeToVolume:0.0
withDuration:1.0
andThen:^{
[player stop];
player.volume = 1.0;
}];

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

- (void) documentsViewControllerSelected:(NSString*)file fromRect:(CGRect)from;
{
lastDocumentRect = from;

scoresViewController.filename = file;
[scoresViewController animateAppearingFrom:from afterDelay:0.1];
[window setRootViewController:scoresViewController animated:YES];
}

- (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];
}];
}

@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;
}

@interface TitlePageView : UIView
{
CAShapeLayer *shapeLayer1;
CALayer *imageLayer;
}

@property (nonatomic, retain) IBOutlet UIButton *playButton;

- (void) startAnimation;
- (void) checkAnimationsRunning;
- (void) stopAnimation;
- (void) setBackgroundImage:(UIImage*)backgroundImage;

@end

-(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"];


}

-(void) stopAnimation
{
[shapeLayer1 removeAllAnimations];
}

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

CoreAudio

Audio

} {
Services

OpenAL Headphones

AVAudioPlayer Speaker
Your code Audio
Session
Audio USB
Queue

Audio
Unit Bluetooth

Audio File
Services

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

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

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.

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.

AVAudioPlayer Services

} {
OpenAL Phones

AVAudioPlayer
Speaker
Code Session

Queue USB

Unit BT

play single sound
(memory or ﬁle)

seek
control level
read level

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

#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;
. . .

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

QA
★★★

&
★★★

Pete Goodliffe @petegoodliffe pete@goodliffe.net

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

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

Advanced iOS

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