Identical Functions, both get executed, no Sound in one - objective-c

Question

I'v googled the problem but couldn't find a similar case.
I've used this tutorial to play the testSound.mp3 - File when hitting a button on the iPad-Simulator:
http://mobileorchard.com/easy-audio-playback-with-avaudioplayer/
It works that way (it plays the sound), if the playSound-Method is in my ViewController.m, but not in my Sound.m (which has a identical method).
The Code gets executed (NSLog says: "Sound.m playSound executed"), but there is no sound at all.
I'd really appreciate some help here, guess I'm totally stuck... :(
Best regards,
- Teapot
// ViewController.h
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import "Sound.h"
#interface ViewController : UIViewController {
AVAudioPlayer *audioPlayer;
}
- (IBAction)pressButton:(id)sender;
- (void)playSound: (NSString*) soundFile volume : (NSInteger) volume repeats : (NSInteger) repeats;
#end
// ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading thea view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)pressButton:(id)sender {
NSLog (#"Method: pressButton");
[self playSound: #"testSound.mp3" volume: 2 repeats: 2 url : url]; //It works!
Sound *tempSound = [[Sound alloc] init];
[tempSound playSound: #"testSound.mp3" volume: 2 repeats: 2]; // Doesn't work. -> Says "Sound.m playSound executed", but there is no Sound.
}
- (void)playSound: (NSString*) soundFile volume : (NSInteger) volume repeats : (NSInteger) repeats {
NSLog(#"ViewControler playSound");
NSError *error;
audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
audioPlayer.numberOfLoops = -1;
if (audioPlayer == nil){
NSLog([error description]);
NSLog(#"ViewController.m playSound NOT executed");
}
else{
[audioPlayer play];
NSLog(#"ViewController.m playSound executed");
}
}
#end
// Sound.h
#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
#interface Sound : NSObject {
AVAudioPlayer *audioPlayer;
}
- (void) playSound: (NSString*) soundFile volume : (NSInteger) volume repeats : (NSInteger) repeats;
#end
// Sound.m
#import "Sound.h"
#implementation Sound
- (void)playSound: (NSString*) soundFile volume : (NSInteger) volume repeats : (NSInteger) repeats {
NSLog(#"Sound playSound");
NSError *error;
audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
audioPlayer.numberOfLoops = -1;
if (audioPlayer == nil){
NSLog([error description]);
NSLog(#"Sound.m playSound NOT executed");
}
else{
[audioPlayer play];
NSLog(#"Sound.m playSound executed");
}
}
#end

Answer 1

There are some inconsistencies in your code: playSound: has an NSString parameter, but AVAudioPlayer inside that method uses a NSURL. Then you set numberOfLoops = -1 (which means infinite repetition) instead of numberOfLoops = repeat.
But the main problem is that here (assuming that you compile with "Automatic Reference Counting")
Sound *tempSound = [[Sound alloc] init];
[tempSound playSound: #"testSound.mp3" volume: 2 repeats: 2];
the tempSound object is deallocated when the pressButton: is left, because no strong references to that object exist anymore.
If you add an instance variable (or property) sound to the view controller class, and assign to that
sound = [[Sound alloc] init];
[sound playSound: #"testSound.mp3" volume: 2 repeats: 2];
then it should work as expected.
Alternatively, you could prevent the Sound object from being deallocated too early by maintaining a "self reference" inside the object, which is removed only when the sound has finished playing:
#interface Sound () <AVAudioPlayerDelegate>
#property(strong, nonatomic) AVAudioPlayer *audioPlayer;
#property(strong, nonatomic) Sound *selfRef;
#end
#implementation Sound
- (void)playSound:(NSString *)soundFile volume:(NSInteger)volume repeats:(NSInteger)repeats
{
NSLog(#"Sound playSound");
NSURL *soundURL = [[NSBundle mainBundle] URLForResource:soundFile withExtension:nil];
NSError *error;
self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundURL error:&error];
if (self.audioPlayer == nil) {
NSLog(#"%#", [error description]);
NSLog(#"Sound.m playSound NOT executed");
} else{
self.audioPlayer.numberOfLoops = repeats;
self.audioPlayer.delegate = self;
[self.audioPlayer play];
self.selfRef = self; // self reference to avoid deallocation
NSLog(#"Sound.m playSound executed");
}
}
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
self.selfRef = nil; // remove self reference
}
#end
Of course, you shouldn't do this with "infinite repetition"!