How does audioPlayerDidFinishPlaying know which file is finished?

I am using AVAudioPlayer to play a 15 audio files. The audio files need to be played in sets of 5 with each set having three files. The three files within a set do not change. The order that the sets are played may change.

I tried using a while loop with isPlaying like this:

while ([backgroundSound isPlaying]) {
    NSLog(@"First while loop");
}
backgroundSoundPath = [[NSBundle mainBundle] pathForResource:@"Set0File1" ofType:@"mp3"]; // *Music filename* 
backgroundSound =[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:backgroundSoundPath] error:nil];
[backgroundSound prepareToPlay];
[backgroundSound play];
while ([backgroundSo开发者_运维百科und isPlaying]) {
    NSLog(@"Second while loop");
}
backgroundSoundPath = [[NSBundle mainBundle] pathForResource:@"Set0File2" ofType:@"mp3"]; // *Music filename* 
backgroundSound =[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:backgroundSoundPath] error:nil];
[backgroundSound prepareToPlay];
[backgroundSound play];
while ([backgroundSound isPlaying]) {
    NSLog(@"Third while loop");
} 

I now realize that this is wrong with the side effect being that the entire UI is locked up for the duration of the file being played.

I know I should be using:

• (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag

But I do not know how audioPlayerDidFinishPlaying is supposed to know exactly which file has finished playing.

I thought it might be like - (void)animationDidStop where you can use a valueForKeyPath to figure out which file was finished playing.

Does it have to be tracked manually?

Any suggestions to point me in the right direction would be appreciated.

Thank you.

---

When an AVAudioPlayer calls the audioPlayerDidFinishPlaying method, it supplies itself as an argument. So what you should do is check the URL to figure out which file just finished playing.

-(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
     if ([player.url isEqual:url1])
     {
         // file which is in url1 stopped playing
     }
     else if ([player.url isEqual:url2])
     {
         // file which is in url2 stopped playing
     }
}