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![Message Syntax
[receiver message];
[receiver message:argument];
[receiver message:arg1 andArg: arg2]
Total 67 Pages
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![Terminology
Message expression
[receiver method:argument]
Message
[receiver method:argument]
Selector
[receiver method:argument]
Method
The code selected by a message.
Total 67 Pages
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![Dot Syntax
Objective-C 2.0 introduced dot syntax
Convenient shorthand for invoking accessor
methods
float height = [person height];
float height = person.height;
[person setHeight: newHeight];
person.height = newHeight;
Follows
the dots…
[[person child] setHeight:newHeight];
//exact the same as
person.child.height = newHeight;
Total 67 Pages
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![Selectors identify methods by name
A selector has type SEL
SEL action = [button action];
[button setAction: @selector(start:)];
Conceptually similar to function pointer
Selectors include the name and all colons,
for example:
-(void) setName:(NSString*)name age:(int)age;
would have a selector:
SEL sel = @selector(setName:age:);
Total 67 Pages
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![Working with selectors
You can determine if an object responds to a
given selector
id obj;
SEL sel = @selector(start:)
if ([obj respondsToSelector:sel]){
[obj performSelector: sel withObject:self];
}
This sort of introspection and dynamic
messaging underlies many Cocoa design
patterns
-(void)setTarget:(id)target;
-(void)setAction:(SEL)action;
Total 67 Pages
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![Working with Classes
You can ask an object about its class
Class myClass = [myObject class];
NSLog(@"My class is %@", [myObject className]);
Testing for general class membership (subclasses
included):
if ([myObject isKindOfClass:[UIControl class]]) {
// something
}
Testing for specific class membership (subclasses
excluded):
if ([myObject isMemberOfClass:[NSString class]]) {
// something string specific
}
Total 67 Pages
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![Working with Objects
Identity v.s. Equality
Identity—testing equality of the pointer
values
if (object1 == object2) {
NSLog(@"Same exact object instance");
}
Equality—testing object attributes
if ([object1 isEqual: object2]) {
NSLog(@"Logically equivalent, but may
be different object instances");
}
Total 67 Pages
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![-description
NSObject implements -description
- (NSString *)description;
Objects represented in format strings using %@
When an object appears in a format string, it is
asked for its description
[NSString stringWithFormat: @”The answer is: %@”,
myObject];
You can log an object’s description with:
NSLog([anObject description]);
Your custom subclasses can override description
to return more specific information
Total 67 Pages
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![Getting raw Accelerometer Data
-(void)initAccelerometer{
[[UIAccelerometer sharedAccelerometer] setUpdateInterval: (1.0 / 100)];
[[UIAccelerometer sharedAccelerometer] setDelegate: self];
}
-(void)accelerometer: (UIAccelerometer*)accelerometer didAccelerate:
(UIAcceleration*) acceleration {
double x, y, z;
x = acceleration.x;
y = acceleration.y;
z = acceleration.z;
//process the data…
}
-(void)disconnectAccelerometer{
[[UIAccelerometer sharedAccelerometer] setDelegate: nil];
}
Total 67 Pages
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![Getting a Location
Starting the location service
-(void)initLocationManager{
CLLocationManager* locManager = [[CLLocationManager alloc] init];
locManager.delegate = self;
[locManager startUpdatingLocation];
}
Using the event data
-(void)locationManager: (CLLocationManager*)manager didUpdateToLocation:
(CLLocation*)newLocation fromLocation: (CLLocation*)oldLocation{
NSTimerInterval howRecent = [newLocation.timestamp timeIntervalSinceNow];
if(howRecent < -10) return;
if(newLocation.horizontalAccuracy > 100) return;
//Use the coordinate data.
double lat = newLocation.coordinate.latitude;
double lon = newLocation.coordinate.longitude;
}
Total 67 Pages
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![AVAudioPlayer
Create from file URL or data
AVAudioPlayer *player;
NSString *path = [[NSBundle mainBundle] pathForResource:… ofType:…];
NSURL *url = [NSURL fileURLWithPath:path];
player = [[AVAudioPlayer allow] initWithContentsOfURL:url];
[player prepareToPlay];
Simple methods for starting/stopping
If(!player.playing){
[player play];
}else{
[player pause];
}
Total 67 Pages
52](https://image.slidesharecdn.com/iphone-lecture-20-20imp-131029232600-phpapp02/85/Iphone-lecture-imp-52-320.jpg)
Uploaded byPragati Singh
Iphone lecture imp
The document provides information about tools and techniques for creating iPhone apps. It discusses Interface Builder, Xcode, and the iOS simulator as tools for app development. It also covers Objective-C programming basics like classes, objects, and the MVC design pattern. Additionally, it summarizes how to access device sensors like the accelerometer and location services to add interactivity to apps. Audio programming on iOS is also briefly mentioned.
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Iphone lecture imp
- 2. Tools to createApps in iPhone Interface Builder Xcode Mac Instruments Simulator/device Total 67 Pages 2
- 3. Sound and MusicComputing We use iPhone to make music! Mobile Music Group ◦ MOGFUN ◦ MOGCLASS ◦ MOGHEALTH Total 67 Pages 3
- 4.
- 5. MOGCLASS Do you wantto create your own iPhone App or develop novel user interface for MOGCLASS? Total 67 Pages 5
- 6. You need toknow… Language: Objective-C and C/C++ Objective Oriented Programming Programming and testing in Xcode Digital Signal Processing basics Assembly Code (ARM) Computer Network Etc… Total 67 Pages 6
- 7. Today we willcover… Objective-C basics Building an Application Sensor programming (accelerometer, GPS, microphone…) Audio Libraries There are a lot of materials about iphone online. What we will cover today is more oriented for your final project. Total 67 Pages 7
- 8. How to learniPhone Programming Recommended Book: None! We’ll use Apple documentation iOS Developer Center: ◦ Download the sample code and learn. http://developer.apple.com/devcenter/ios/index.action Write the code by yourself… Trial and error. Total 67 Pages 8
- 9. iPhone SDK Technology Architecture Cocoa Touch • • • • • Multi-TouchEvents Multi-Touch Controls Accelerometer View Hierarchy Localization Alerts Web View People Picker Image Picker Camera Media • • • • • Core Audio OpenAL Audio Mixing Audio Recording Video Playback JPG, PNG,TIFF PDF Quartz (2D) Core Animation OpenGL ES Core Services • • • • • Collections Address Book Networking File Access SQLite Core Location Net Services Threading Preference URL utilities Core OS • • • • • OS X Kernel Mach 3.0 BSD Sockets Security Power Mgmt Keychain Certificates File System Bonjour Total 67 Pages 9
- 10. Outlines Objective-C basics Buildingan Application Sensor programming (accelerometer, GPS, microphone…) Audio Libraries Total 67 Pages 10
- 11. OOP Vocabulary Class: definesthe grouping of data and code, the ―type‖ of an object. Instance: a specific allocation of a class. Method: a ―function‖ that an object knows how to perform. Instance Variable (or ―ivar‖): a specific piece of data belonging to an object. Total 67 Pages 11
- 12. OOP Vocabulary Encapsulation Polymorphism Inheritance ◦ Keepimplementing private and separate from interface ◦ Different objects, same interface ◦ Hierarchical organization, share code, customize or extend behaviors Total 67 Pages 12
- 13. Objective-C Strict superset ofC ◦ Mix C with ObjC ◦ Or even C++ with ObjC (usually referred to as ObjC++) A very simple language, but some new syntax Single inheritance, classes inherit from one and only one superclass Protocols define behavior that cross classes Dynamic runtime Loosely typed, if you’d like Total 67 Pages 13
- 14. Class and InstanceMethods Instance respond to instance methods -(id)init; -(float)height; -(void)walk; • Classes respond to class methods +(id)alloc; +(id)person; +(Person*)sharedPerson; Total 67 Pages 14
- 15. Message Syntax [receiver message]; [receivermessage:argument]; [receiver message:arg1 andArg: arg2] Total 67 Pages 15
- 16. Terminology Message expression [receiver method:argument] Message [receivermethod:argument] Selector [receiver method:argument] Method The code selected by a message. Total 67 Pages 16
- 17. Dot Syntax Objective-C 2.0introduced dot syntax Convenient shorthand for invoking accessor methods float height = [person height]; float height = person.height; [person setHeight: newHeight]; person.height = newHeight; Follows the dots… [[person child] setHeight:newHeight]; //exact the same as person.child.height = newHeight; Total 67 Pages 17
- 18. Dynamic and statictyping Dynamically-typed object id anObject just id Not id * (unless you really, really mean it…) Statically-typed object Person *anObject Objective-C provides compile-time, not runtime, type checking Objective-C always uses dynamic binding Total 67 Pages 18
- 19. Selectors identify methodsby name A selector has type SEL SEL action = [button action]; [button setAction: @selector(start:)]; Conceptually similar to function pointer Selectors include the name and all colons, for example: -(void) setName:(NSString*)name age:(int)age; would have a selector: SEL sel = @selector(setName:age:); Total 67 Pages 19
- 20. Working with selectors Youcan determine if an object responds to a given selector id obj; SEL sel = @selector(start:) if ([obj respondsToSelector:sel]){ [obj performSelector: sel withObject:self]; } This sort of introspection and dynamic messaging underlies many Cocoa design patterns -(void)setTarget:(id)target; -(void)setAction:(SEL)action; Total 67 Pages 20
- 21. Working with Classes Youcan ask an object about its class Class myClass = [myObject class]; NSLog(@"My class is %@", [myObject className]); Testing for general class membership (subclasses included): if ([myObject isKindOfClass:[UIControl class]]) { // something } Testing for specific class membership (subclasses excluded): if ([myObject isMemberOfClass:[NSString class]]) { // something string specific } Total 67 Pages 21
- 22. Working with Objects Identityv.s. Equality Identity—testing equality of the pointer values if (object1 == object2) { NSLog(@"Same exact object instance"); } Equality—testing object attributes if ([object1 isEqual: object2]) { NSLog(@"Logically equivalent, but may be different object instances"); } Total 67 Pages 22
- 23. -description NSObject implements -description -(NSString *)description; Objects represented in format strings using %@ When an object appears in a format string, it is asked for its description [NSString stringWithFormat: @”The answer is: %@”, myObject]; You can log an object’s description with: NSLog([anObject description]); Your custom subclasses can override description to return more specific information Total 67 Pages 23
- 24. Foundation Framework Foundation Classes ◦NSObject String NSString / NSMutableString Collection NSArray / NSMutableArray NSDictionary / NSMutableDictionary NSSet / NSMutableSet NSNumber Others NSData / NSMutableData NSDate / NSCalendarDate Total 67 Pages 24
- 25. More OOP Info Tonsof books and articles on OOP Objective-C 2.0 Programming Language Total 67 Pages 25
- 26. Outlines Objective-C basics Buildingan Application Sensor programming (accelerometer, GPS, microphone…) Audio Libraries Total 67 Pages 26
- 27. Anatomy of anApplication Compiled code Nib files ◦ Your code ◦ Frameworks ◦ UI elements and other objects ◦ Details about object relations Resources (images, sounds, strings, etc) Info.plist file (application configuration) Total 67 Pages 27
- 28. App Lifecycle Total 67Pages 28
- 29. App Lifecycle Main function UIApplicationMain which Info.plist to figure out what nib to load. MainWindow.xib contains the connections for our application. AppDelegate ViewController.xib View – handle UI events Total 67 Pages 29
- 30.
- 31. Communication and MVC Total67 Pages 31
- 32. Model Manages the appdata and state Note concerned with UI or presentation Often persists somewhere Same model should be reusable, unchanged in different interfaces Total 67 Pages 32
- 33. View Present the Modelto the user in an appropriate interface Allows user to manipulate data Does not store any data ◦ (except to cache state) Easily reusable & configurable to display different data Total 67 Pages 33
- 34. Controller Intermediary between Model& View Updates the view when the model changes Updates the model when the user manipulates the view Typically where the app logic lives Total 67 Pages 34
- 35. Outlines Objective-C basics Buildingan Application Sensor programming (accelerometer, GPS, microphone, …) Audio Libraries Total 67 Pages 35
- 36. Accelerometer What are theaccelerometers? ◦ Measure changes in force What are the uses? Physical Orientation vs. Interface Orientation ◦ Ex: Photos & Safari Total 67 Pages 36
- 37. Orientation-Related Changes Getting thephysical orientation ◦ UIDevice class UIDeviceOrientationDidChangeNotification Getting the interface orientation ◦ UIApplication class statusBarOrientation property ◦ UIViewController class interfaceOrientation property Total 67 Pages 37
- 38. Shake Undo! UIEvent type ◦ @property(readonly)UIEventType type; ◦ @property(readonly) UIEventSubtype subtype; ◦ UIEventTypeMotion ◦ UIEventSubtypeMotionShake Total 67 Pages 38
- 39. Getting raw AccelerometerData 3-axis data Configurable update frequency (10-100Hz) Sample Code (AccelerometerGraph) Class Protocol ◦ UIAccelerometer ◦ UIAcceleration ◦ UIAccelerometerDelegate Total 67 Pages 39
- 40. Getting raw AccelerometerData -(void)initAccelerometer{ [[UIAccelerometer sharedAccelerometer] setUpdateInterval: (1.0 / 100)]; [[UIAccelerometer sharedAccelerometer] setDelegate: self]; } -(void)accelerometer: (UIAccelerometer*)accelerometer didAccelerate: (UIAcceleration*) acceleration { double x, y, z; x = acceleration.x; y = acceleration.y; z = acceleration.z; //process the data… } -(void)disconnectAccelerometer{ [[UIAccelerometer sharedAccelerometer] setDelegate: nil]; } Total 67 Pages 40
- 41. Filtering Accelerometer Data Low-passfilter High-pass filter ◦ Isolates constant acceleration ◦ Used to find the device orientation ◦ Shows instantaneous movement only ◦ Used to identify user-initiated movement Total 67 Pages 41
- 42. Filtering Accelerometer Data Total67 Pages 42
- 43. Filtering Accelerometer Data Total67 Pages 43
- 44. Applying Filters Simple low-passfilter example #define FILTERFACTOR 0.1 Value = (newAcceleration * FILTERFACTOR) + (previousValue * (1.0 – FILTERFACTOR)); previousValue = value; Simple high-pass filter example lowpassValue = (newAcceleration * FILTERFACTOR) + (previousValue * (1.0 – FILTERFACTOR)); previousLowPassValue = lowPassValue; highPassValue = newAcceleration – lowPassValue; Total 67 Pages 44
- 45. GPS Classes Protocol ◦ CLLocationManager ◦ CLLocation ◦CLLocationManagerDelegate Total 67 Pages 45
- 46. Getting a Location Startingthe location service -(void)initLocationManager{ CLLocationManager* locManager = [[CLLocationManager alloc] init]; locManager.delegate = self; [locManager startUpdatingLocation]; } Using the event data -(void)locationManager: (CLLocationManager*)manager didUpdateToLocation: (CLLocation*)newLocation fromLocation: (CLLocation*)oldLocation{ NSTimerInterval howRecent = [newLocation.timestamp timeIntervalSinceNow]; if(howRecent < -10) return; if(newLocation.horizontalAccuracy > 100) return; //Use the coordinate data. double lat = newLocation.coordinate.latitude; double lon = newLocation.coordinate.longitude; } Total 67 Pages 46
- 47. Getting a Heading GeographicNorth Magnetic North ◦ CLLocationDirection trueHeading ◦ CLLocationDirection magneticHeading -(void)locationManager: (CLLocationManager *)manager didUpdateHeading:(CLHeading*)newHeading{ //Use the coordinate data. CLLocationDirection heading = newHeading.trueHeading; CLLocationDirection magnetic = newHeading.magneticHeading; } Total 67 Pages 47
- 48. Microphone We will coverit in the audio library… Total 67 Pages 48
- 49. Outlines Objective-C basics Buildingan Application Sensor programming (accelerometer, GPS, microphone…) Audio Libraries Total 67 Pages 49
- 50. Audio Libraries System SoundAPI – short sounds AVAudioPlayer – ObjC, simple API Audio Session - Audio Toolbox Audio Queue - Audio Toolbox Audio Units OpenAL MediaPlayer Framework Total 67 Pages 50
- 51. AVAudioPlayer Play longer sounds(> 5 seconds) Locally stored files or in-memory (no network streaming) Can loop, seek, play, pause Provides metering Play multiple sounds simultaneously Cocoa-style API Supports many more formats Sample Code: avTouch ◦ Initialize with file URL or data ◦ Allows for delegate ◦ Everything the AudioFile API supports Total 67 Pages 51
- 52. AVAudioPlayer Create from fileURL or data AVAudioPlayer *player; NSString *path = [[NSBundle mainBundle] pathForResource:… ofType:…]; NSURL *url = [NSURL fileURLWithPath:path]; player = [[AVAudioPlayer allow] initWithContentsOfURL:url]; [player prepareToPlay]; Simple methods for starting/stopping If(!player.playing){ [player play]; }else{ [player pause]; } Total 67 Pages 52
- 53. Audio Sessions Handles audiobehavior at the application, inter-application, and device levels ◦ ◦ ◦ ◦ Ring/Silent switch? iPod audio continue? Headset plug / unplug? Phone call coming? Sample Code: avTouch & aurioTouch Total 67 Pages 53
- 54. Audio Sessions Six audiosession categories ◦ ◦ ◦ ◦ ◦ ◦ Ambient Solo Ambient (Default session) Media playback Recording Play and record Offline audio processing Total 67 Pages 54
- 55. Audio Queue Audio FileStream Services & Audio Queue Services Supports wider variety of formats Finer grained control over playback ◦ Streaming audio over network ◦ Cf: AVAudioPlayer(local) Allows queueing of consecutive buffers for seamless playback ◦ Callback functions for reusing buffers Sample code: SpeakHere Total 67 Pages 55
- 56. Audio Units For seriousaudio processing Graph-based audio ◦ ◦ ◦ ◦ Rate or format conversion Real time input/output for recording & playback Mixing multiple streams VoIP (Voice over Internet Protocol). Very, very powerful. Sample code: aurioTouch Total 67 Pages 56
- 57. Audio Units Lowest programminglayer in iOS audio stack ◦ Real-time playback of synthesized sounds ◦ Low-latency I/O ◦ Specific audio unit features Otherwise, look first at the Media Player, AV Foundation, OpenAL, or Audio Toolbox! Total 67 Pages 57
- 58. Audio Units Ex: Karaokeapp in iPhone ◦ real-time input from mic ◦ Real-time output to speaker ◦ Audio Unit provides excellent responsiveness ◦ Audio Unit controls audio flow to do pitch tracking, voice enhancement, iPod equalization, and etc. Total 67 Pages 58
- 59. OpenAL High level, cross-platformAPI for 3D audio mixing Models audio in 3D space Sample code: oalTouch More information: http://www.openal.org/ ◦ Great for games ◦ Mimics OpenGL conventions ◦ Buffers: Container for Audio ◦ Sources: 3D point emitting Audio ◦ Listener: Position where Sources are heard Total 67 Pages 59
- 60. MediaPlayer Framework Tell iPodapp to play music Access to entire music library ◦ For playback, not processing Easy access through MPMediaPickerController Deeper access through Query APIs Sample code: AddMusic Total 67 Pages 60
- 61. Others Accelerate Framework Bonjour andNSStream ◦ C APIs for vector and matrix math, digital signal processing large number handling, and image processing ◦ vDSP programming guide The Synthesis ToolKit in C++ (STK) and OSC Total 67 Pages 61
- 62. More Info forBeginners iPhone Application Programming (Standford University - iTunes University) Dan Pilone & Tracey Pilone. Head First iPhone Development. Total 67 Pages 62
- 63. Thank you andgood luck to your final projects! Total 67 Pages 63