tableview with AVAudioPlayer

Question

In one of my view controllers I have a tableview with custom tableviewcells. Each cell is associated with a unique audio file. Each cell also has a progress bar. When I tap the cells to play the audio file and scroll down, I notice that the progress bar of the reused cell is also updating. I created a custom NSObject class called OSTablePlayerController that contains the AVAudioPlayer and its functionality. However, I set the NSTimer within my custom tableviewcell class. When I tap a cell to play the following method gets called within my custom tableviewcell class:

-(void) rowSelected2: (NSURL*) url
{
    self.audioPlayer = [OSTablePlayerController getInstance];
    NSData *data=[NSData dataWithContentsOfURL:url];
    [self.audioPlayer playAudio:data];
    self.audioPlayer.isPlayerPlaying = YES;
    self.timer = [NSTimer timerWithTimeInterval:0.01 target:self selector:@selector(updateProgress:) userInfo:nil repeats:YES];
    [[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];  
}  

- (void)updateProgress:(NSTimer *)timer 
{

    NSTimeInterval playTime = [self.audioPlayer currentTime];
    NSTimeInterval duration = [self.audioPlayer duration];

    float progress =  playTime/duration;

    [self.waveView setProgress:progress];

    if(!(self.audioPlayer.player.playing))
    {
        [self audioPlayerDidFinishPlaying:self.audioPlayer.player successfully:YES];

        progress = 0.00;

        [self.waveView setProgress:progress];

    }
}

-(void) audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
    if(flag)
    {
        [self.timer invalidate];
        self.audioPlayer.isPlayerPlaying = NO;
    }
}

The only other functionality I have implemented is pause, so that when a cell is tapped while it is already playing, the player would get paused. Tapping it again would start the player from where it was paused.

Anyone have recommendations on how to go about doing this the right way? I expect this to get pretty messy.

EDIT: Attempting to incorporate delegate methods.

//Custom tableview cell class .h
@class OSAudioTableCell;
@protocol progressDelegate <NSObject>

-(float) trackProgress;

@end

@interface OSAudioTableCell : UITableViewCell <AVAudioPlayerDelegate>
{

}

@property (nonatomic, weak) id<progressDelegate> delegate;   

//Custom table view cell .m file
-(void) rowSelected2
{
        [self.waveView setProgress:[self.delegate trackProgress]];
}

-(void) prepareForReuse
{
    [super prepareForReuse];
    [self.timer invalidate];
    self.waveView.progress = 0;    
}

//view controller with tableview 
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
 {
             [((OSAudioTableCell*)[self.audioTable cellForRowAtIndexPath:indexPath]) rowSelected2];
             self.audioPlayer = [[OSTablePlayerController alloc] init];
             [self.audioPlayer playAudio:data];
             self.audioPlayer.isPlayerPlaying = YES;
             self.audioPlayer.playerTimer =[NSTimer timerWithTimeInterval:0.01 target:self selector:@selector(trackProgress:) userInfo:nil repeats:YES];
             [[NSRunLoop mainRunLoop] addTimer:self.audioPlayer.playerTimer forMode:NSRunLoopCommonModes];
}

-(float) trackProgress
{
    NSTimeInterval playTime = [self.audioPlayer currentTime];
    NSTimeInterval duration = [self.audioPlayer duration];

    float progress =  playTime/duration;

    if(!(self.audioPlayer.player.playing))
    {
        [self audioPlayerDidFinishPlaying:self.audioPlayer.player successfully:YES];

        progress = 0.00;
    }

    return progress;
 }

Answer 1

Use a property to track which cell is currently selected and playing the audio.

Use a property say selectedIndexPath.When you tap on cell assign this property with current tapped indexpath.In cellForRowAtIndexPath compare selectedIndexPath with the current cell returning if selectedIndexPath match than show progress bar else hide for all which do not match.

- (UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

    // your other code
   if([selectedIndexPath isEqual:indexPath]){

      //allocate progressbar and start timer

   }
   else{
     //deallocate progressbar and invalidate timer
   }

}

You can check in didSelectRowAtIndexPath whether selectedIndexPath is equal to current tap cell if so than check for audioPlayer playing status if it is playing than pause it else start it again

Answer 2

In your UITableViewCell subclass, you should implement prepareForReuse. In this method, return your cell to its default state (exactly as it is after the first time it's initialized).

Then, in cellForRowAtIndexPath: every time you dequeue a cell it will be fresh. Just configure it as appropriate for the item at the current index path. If that's the item that playing, update and start the progress bar. If it's not, then don't.

I think your general problem is that each cell is maintaining its own timer and audio player, but there should only be one of these (in your controller, not in your cell subclass). Your cell is a view, and should therefore be as stupid as possible. It shouldn't have any idea what it's displaying, or what happens when it's tapped. It should just communicate to the controller when it's tapped, and the controller should do the rest.