AVAudioPlayer fade volume out

Question

I have an AVAudioPlayer playing some audio (duh!)

The audio is initiated when the user presses a button. When they release it I want the audio to fade out.

I

Answer 1

How about this: (if time passed in is negative then fade out the sound, otherwise fade in)

- (void) fadeInOutVolumeOverTime: (NSNumber *)time
{
#define fade_out_steps  0.1
    float           theVolume = player.volume;
    NSTimeInterval  theTime = [time doubleValue];
    int             sign = (theTime >= 0) ? 1 : -1;

// before we call this, if we are fading out, we save the volume
// so that we can restore back to that level in the fade in
    if ((sign == 1) &&
            ((theVolume >= savedVolume) ||
                            (theTime == 0))) {
        player.volume = savedVolume;
    }
    else if ((sign == -1) && (theVolume <= 0)) {
        NSLog(@"fading");
        [player pause];
        [self performSelector:@selector(fadeInOutVolumeOverTime:) withObject:[NSNumber numberWithDouble:0] afterDelay:1.0];

    }
    else {
        theTime *= fade_out_steps;
        player.volume = theVolume + fade_out_steps * sign;
        [self performSelector:@selector(fadeInOutVolumeOverTime:) withObject:time afterDelay:fabs(theTime)];
    }
}