Checking whether the audio has ended playing in iOS - ios

Question

I would like to check whether the audio has ended playing. If so, I need to change the button to a play button instead of a pause button. How do i do it in iOS?
My code looks like this:
-(void)playAudioFile:(BOOL)status
{
NSString *soundFilePath = [[NSBundle mainBundle] pathForResource:#"audio" ofType:#"mp3"];
NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];
NSError *error;
if(status)
{
if(!audioPlayer)
{
audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundFileURL error:&error];
audioPlayer.currentTime = currentPlayTime;
audioPlayer.numberOfLoops = 0; //Infinite
audioDuration = audioPlayer.duration;
audioPlaySlider.minimumValue = 0;
audioPlaySlider.maximumValue = audioDuration;
audioPlaySlider.value = currentPlayTime;
[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(audioTimer:) userInfo:[NSDictionary dictionaryWithObject:audioPlayer forKey:#"playerObject"] repeats:YES];
}
[audioPlayer play];
if([audioPlayer rate] != 1.0 )
{
[audioPlayer play];
}
else
{
[self->audioPlayBtn setBackgroundImage:[UIImage imageNamed:#"playBtn.png"] forState:UIControlStateNormal];
}
NSLog(#"Play duration : %f",audioDuration);
}
else
{
if(audioPlayer && audioPlayer.playing)
{
[audioPlayer pause];
}
}
NSLog(#"Error for file : %#",error);
}
I tried this:
if([audioPlayer rate] != 1.0 )
{
[audioPlayer play];
}
else
{
[self->audioPlayBtn setBackgroundImage:[UIImage imageNamed:#"playBtn.png"] forState:UIControlStateNormal];
}
But not working.. Need some guidance...

Answer 1

Use the AVAudioPlayerDelegate's method
- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
Your viewcontroller/class with the audioplayer instance must be the delegate for the audio player. The method will be called when the audio player finishes playback.
http://developer.apple.com/library/ios/#documentation/AVFoundation/Reference/AVAudioPlayerDelegateProtocolReference/Reference/Reference.html