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

static NSString *CellIdentifier = @"Cell";
cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Download Button
DownloadButtonCell=[[UIButton alloc]initWithFrame:CGRectMake(10, 30, 48, 48)];
[DownloadButtonCell setImage:[UIImage imageNamed:@"download.png"] forState:UIControlStateNormal];
DownloadButtonCell.tag=111;
[DownloadButtonCell addTarget:self action:@selector(startDownload:)
                 forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:DownloadButtonCell];
return cell;
}

-(void)startDownload:(id)sender
{
CGPoint buttonPosition=[sender convertPoint:CGPointZero toView:self.tableview];
NSIndexPath *indexPath = [self.tableview indexPathForRowAtPoint:buttonPosition];
NSLog(@"%ld",(long)indexPath.row);

LLACircularProgressView *progressView=[[LLACircularProgressView alloc]initWithFrame:CGRectMake(20, 40, 25, 25)];
progressView.tintColor = [UIColor greenColor];
[progressView addTarget:self action:@selector(stopDownload:) forControlEvents:UIControlEventTouchUpInside];

[[[tableview cellForRowAtIndexPath:indexPath] viewWithTag:111]removeFromSuperview];
[[[tableview cellForRowAtIndexPath:indexPath]contentView] addSubview:progressView];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:[mp3Array objectAtIndex:indexPath.row]]];
operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
NSString *pdfName = [[idArray objectAtIndex:indexPath.row] stringByAppendingString:@".mp3"];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [[paths objectAtIndex:0] stringByAppendingPathComponent:pdfName];
operation.outputStream = [NSOutputStream outputStreamToFileAtPath:path append:NO];

[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"Successfully downloaded file to %@", path);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];
[operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {

    progressView.progress=(float)totalBytesRead / totalBytesExpectedToRead;
}];
[operation start];
}

//DownloadableTableViewCell.h
@interface DownloadableTableViewCell : UITableViewCell
@property (assign, nonatomic, getter=isDownloading) BOOL downloading;
@end

//DownloadabletableViewCell.m
@interface DownloadableTableViewCell()
@property (strong, nonatomic) UIView *downloadButton;
@property (strong, nonatomic) UIView *progressView;
@end

@implementation
-(id)initWithStyeleBlahblah{
   self = [super initWithStyleBlahBlah];
   if (self){
      //init download button, init progress view.

      //add download button to view.
   }
   return self;
}

-(void)setDownloading:(BOOL)downloading{
   _downloading = downloading;
   if (_downloading){
      //add progress view to contentview.
      //remove download button.
   }
   else{
      //add button to contentView;
      //remove progress view;
   }
}


-(void)prepareForReuse{
   [super prepareForReuse];
   self.downloading = NO;
}