iPhone App: not resuming audio session in AVAudio Player - iphone

Question

In my iPhone App I am Playing music using AVAudioPlayer. when my App runs in background that time also it is running for tht I wrote this code
in AppDelegate on
-- application didFinishLaunchingWithOptions
audioManager= [[AudioManager alloc] init];
audioManager.delegate=self;
audioManager.soundFile=[[[NSBundle mainBundle] pathForResource:#"mysong" ofType:#"wav"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
[audioManager setFileForPlay];
[audioManager.player setNumberOfLoops:-1];
[audioManager.player setVolume:.5];
[audioManager play];
-(void) playerBeginInterruption:(AVAudioPlayer *)p{
[usdef setValue:#"START" forKey:#"LOCATIONMANAGER"];
[locationManager startUpdatingLocation];
[p pause];
// audioManager=nil;
}
-(void) playerBeginInterruptionInBackground:(AVAudioPlayer *)p{
[usdef setValue:#"START" forKey:#"LOCATIONMANAGER"];
[locationManager startUpdatingLocation];
[p pause];
//audioManager=nil;
}
-(void) playerEndInterruption:(AVAudioPlayer *)p{
NSLog(#"Inteerpt END");
[p prepareToPlay];
[p play];
[usdef setValue:#"STOP" forKey:#"LOCATIONMANAGER"];
}
-(void) playerEndInterruptionInBackgroud:(AVAudioPlayer *)p{
NSLog(#"Inteerpt END BG");
// [self performSelector:#selector(allocaudioManager)];
[p prepareToPlay];
[p play];
[usdef setValue:#"STOP" forKey:#"LOCATIONMANAGER"];
// [locationManager stopUpdatingLocation];
}
now i have created saperate classes for audio manager which handels the delegate methods
in .h file
#import <Foundation/Foundation.h>
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>
#protocol AudioManagerDelegate;
#interface AudioManager : NSObject <AVAudioPlayerDelegate> {
AVAudioPlayer *player;
NSString *soundFile;
BOOL inBackground;
id<AudioManagerDelegate> delegate;
}
#property (nonatomic, assign) id<AudioManagerDelegate>delegate;
#property (nonatomic, retain) NSString *soundFile;
#property (nonatomic, assign) AVAudioPlayer *player;
#property (nonatomic, assign) BOOL inBackground;
- (void)play;
- (void)pause;
- (void)stop;
- (void)registerForBackgroundNotifications;
-( void) setFileForPlay;
#end
#protocol AudioManagerDelegate <NSObject>
#optional
- (void)playerDidFinishPlayingInBackground:(AVAudioPlayer*)p;
- (void)playerDidFinishPlaying:(AVAudioPlayer*)p;
- (void)playerBeginInterruption:(AVAudioPlayer*)p;
- (void)playerBeginInterruptionInBackground:(AVAudioPlayer*)p;
- (void)playerEndInterruption:(AVAudioPlayer *)p;
- (void)playerEndInterruptionInBackgroud:(AVAudioPlayer *)p;
#end
in .m file
#implementation AudioManager
#synthesize delegate;
#synthesize player;
#synthesize inBackground;
#synthesize soundFile;
void RouteChangeListener(void *inClientData, AudioSessionPropertyID inID,UInt32 inDataSize, const void *inData);
-(id) init
{
if((self=[super init]))
{
OSStatus result = AudioSessionInitialize(NULL, NULL, NULL, NULL);
if (result)
NSLog(#"Error initializing audio session! %ld", result);
[[AVAudioSession sharedInstance] setDelegate: self];
NSError *setCategoryError = nil;
[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: &setCategoryError];
if (setCategoryError)
NSLog(#"Error setting category! %#", setCategoryError);
result = AudioSessionAddPropertyListener (kAudioSessionProperty_AudioRouteChange, RouteChangeListener, self);
if (result)
NSLog(#"Could not add property listener! %ld", result);
return self;
}
return nil;
}
-(void) setFileForPlay{
self.player=nil;
player = [[AVAudioPlayer alloc] initWithData:[NSData dataWithContentsOfFile:self.soundFile] error:nil];//initWithContentsOfURL:[NSURL URLWithString:self.soundFile] error:nil];
if (self.player)
{
player.delegate = self;
}
}
-(void) play{
[self.player play];
}
-(void)pause{
[self.player pause];
NSLog(#"in Pause");
}
-(void)stop{
[self.player stop];
NSLog(#"in stop");
}
void RouteChangeListener(void *inClientData, AudioSessionPropertyID inID,UInt32 inDataSize, const void *inData){
AudioManager* This = (AudioManager*)inClientData;
if (inID == kAudioSessionProperty_AudioRouteChange) {
CFDictionaryRef routeDict = (CFDictionaryRef)inData;
NSNumber* reasonValue = (NSNumber*)CFDictionaryGetValue(routeDict, CFSTR(kAudioSession_AudioRouteChangeKey_Reason));
int reason = [reasonValue intValue];
if (reason == kAudioSessionRouteChangeReason_OldDeviceUnavailable) {
[This stop];
}
}
}
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)p successfully:(BOOL)flag
{
if (flag == NO)
NSLog(#"Playback finished unsuccessfully");
[p setCurrentTime:0.];
if (inBackground)
{
[delegate playerDidFinishPlayingInBackground:p];
}
else
{
[delegate playerDidFinishPlaying:p];
}
}
- (void)playerDecodeErrorDidOccur:(AVAudioPlayer *)p error:(NSError *)error
{
NSLog(#"ERROR IN DECODE: %#\n", error);
}
// we will only get these notifications if playback was interrupted
- (void)audioPlayerBeginInterruption:(AVAudioPlayer *)p
{
NSLog(#"Interruption begin ");
// the object has already been paused, we just need to update UI
if (inBackground)
{
[delegate playerBeginInterruptionInBackground:p];
}
else
{
[delegate playerBeginInterruption:p];
}
}
- (void)audioPlayerEndInterruption:(AVAudioPlayer *)p withFlags:(NSUInteger)flags
{
if(inBackground)
{
[delegate playerEndInterruptionInBackgroud:p];
}
else
{
[delegate playerEndInterruption:p];
}
NSLog(#"Interruption ended. Resuming playback");
}
- (void)registerForBackgroundNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(setInBackgroundFlag)
name:UIApplicationWillResignActiveNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(clearInBackgroundFlag)
name:UIApplicationWillEnterForegroundNotification
object:nil];
}
- (void)setInBackgroundFlag
{
inBackground = true;
}
- (void)clearInBackgroundFlag
{
inBackground = false;
}
#end
Now the problem is if I am Playing any songs form ipod library and stop the song and closing the ipod library, my original avaudioplayer which was playing before starting ipos library is not resuming means it is not playong song again
what could be wrong?
is there any demo project or sample code which can help me?
Please help and suggest.

Answer 1

You shouldn't have to call pause on the AVAudioPlayer (p in your code) in audioPlayerBeginInterruption: the player should not be playing at that stage because of the interruption. In audioPlayerEndInterruption: the following usually works for me:
[p prepareToPlay];
[p play];
The Audio Session Cookbook in the iOS docs has a section on "Handling Interruptions with the AVAudioPlayer Class" that should also help.