Making a sound

• When we fire a bullet, we will play a sound

• The AVFoundation framework enables us to add sounds to our app

AVFoundation framework

• We need to import that framework into our project (it is not in the frameworks folder)

• In Project Navigator, select Build Phases tab, Select Link Binary With Libraries, +, choose AVFoundation Framework

• It shows up in the frameworks folder

AVFoundation framework

#import <AVFoundation/AVFoundation.h>

• We will use the AVAudioPlayer class

• It encapsulates a sound: it enables us to play a sound, stop playing the sound, set the volume, ..

• Note: need to import the sound into the resources folder

.h file

• Add an AVAudioPlayer instance variableAVAudioPlayer *cannonFireSound;• In the .m file, we need to find this sound

file, allocate memory for and initialize the object above

.m file

• Inside initWithFrame method• The method initWithContentsOfURL, from

class AVAudioPlayer, takes a NSURL argument representing the url path of the sound file

• From a string representing a regular file path, we can build a NSURL object

.m file

• Get File pathNSString *soundPath = [[NSBundle

mainBundle] pathForResource:@”cannon_fire” ofType:@”wav”];

• Build NSURL objectNSURL *fileURL = [[NSURL alloc]

initFileURLWithPath:soundPath];

.m file

• Allocate memory and initialize hitPlayercannonFireSound = [[AVAudioPlayer alloc]

initWithContentsOfURL:fileURL error:nil];• Now we can set the volume, play the sound,

pause, stop, ..• More at developer.apple….cannonFireSound.volume = 0.9; // between 0

and 1[cannonFireSound play];

.m file

• We used the alloc method to allocate memory for and create the fileURL object

• In previous versions of Xcode only (but not with Xcode 5)

we own that object, we are responsible for releasing it

[fileURL release];

AVAudioPlayer

• There may be a lag the first time you play a sound

preload the sound using the prepareToPlay method

[cannonFireSound prepareToPlay];

Making a sound when cannon is fired

• When do we fire the cannon?• The cannon will fire based on user double

tapping• We need to add some code to the processTouch

method and capture a double tap

Making a sound when cannon is fired

• Cannon is fired on a double tap by the user• In processTouch methodif( touch.tapCount == 2 )

[cannonFireSound play];