Question

New to IOS dev, I’m testing AVAudioplayer to play sound on iPad2 (Xcode 4.2 project, ARC/storyboard enabled). Sound plays ok in simulator and no error. No error on device either but no sound.

Been browsing this fine resource temple, but nothing I’ve tried based on feedback here has produced anything but deafening iPad silence. Could someone help? My .h:

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>

@interface ViewController : UIViewController
<AVAudioPlayerDelegate>
{
    AVAudioPlayer *audioPlayer;
    UISlider *volumeControl;
    UILabel *timerLabel;
    NSTimer *playbackTimer;
}
@property (nonatomic, retain) IBOutlet UISlider *volumeControl;
@property (nonatomic, retain) IBOutlet UILabel *timerLabel;
@property (nonatomic, retain) NSTimer *playbackTimer;
@property (nonatomic, strong) AVAudioPlayer *audioPlayer;
-(IBAction) playAudio;
-(IBAction) stopAudio;
-(IBAction) adjustVolume;
@end

My .m:

#import "ViewController.h"

@implementation ViewController
@synthesize volumeControl, timerLabel, playbackTimer, audioPlayer;

-(void)playAudio
{
    playbackTimer = [NSTimer scheduledTimerWithTimeInterval:1.0
                                                     target:self
                                                   selector:@selector(updateTime)
                                                   userInfo:nil
                                                    repeats:YES];
    [audioPlayer play];
}

-(void)stopAudio
{
    [playbackTimer invalidate];
    [audioPlayer stop];
}
-(void)adjustVolume
{
    if (audioPlayer != nil)
    {
        audioPlayer.volume = volumeControl.value;
    }
} 

-(void)updateTime
{
    float minutes = floor(audioPlayer.currentTime/60);
    float seconds = audioPlayer.currentTime - (minutes * 60);

    float duration_minutes = floor(audioPlayer.duration/60);
    float duration_seconds = 
    audioPlayer.duration - (duration_minutes * 60);

    NSString *timeInfoString = [[NSString alloc] 
                                initWithFormat:@"%0.0f.%0.0f / %0.0f.%0.0f",
                                minutes, seconds, 
                                duration_minutes, duration_seconds];

    timerLabel.text = timeInfoString;
}


-(void)audioPlayerDidFinishPlaying:
(AVAudioPlayer *)player successfully:(BOOL)flag
{
}
-(void)audioPlayerDecodeErrorDidOccur:
(AVAudioPlayer *)player error:(NSError *)error
{
}
-(void)audioPlayerBeginInterruption:(AVAudioPlayer *)player
{
}
-(void)audioPlayerEndInterruption:(AVAudioPlayer *)player
{
}

my viewDidLoad:

 - (void)viewDidLoad {
        [super viewDidLoad];

        NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle]
                                             pathForResource:@"song"
                                             ofType:@"mp3"]];

        NSError *error;
        audioPlayer = [[AVAudioPlayer alloc]
                       initWithContentsOfURL:url
                       error:&error];
        if (error)
        {
            NSLog(@"Error in audioPlayer: %@", 
                  [error localizedDescription]);
        } else {
            audioPlayer.delegate = self;
            [audioPlayer prepareToPlay];
        }

    [super viewDidLoad];
}

Answer 1

Make sure that the file is indeed an mp3 format. Make sure that you are copying the file into the bundle, and not playing off of local path on your desktop. Check the device volume. Check the return BOOL from the play call. all of these are possible explanations.