iphone - Correct way to show downloadable content in UITableView (with ProgressBar etc.)

I think this a rather complex question. I have a TableView that displays a number of downloadable content. When you click it on a button within the cell the download starts.

But I'm having several issues: 1.How can I make sure that the progressBar will be shown all the time (even if the user scrolls scrolls and the cell will be reloaded) 2.How can I make sure that the user can download 2 files at once. I'm afraid it causes issues because I use some instance Variables. In a way it should work a bit like downloading from iCloud in the Music App

Here is my code

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath  {      static NSString *CellIdentifier = @"Cell";        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];      if (cell == nil) {          cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:nil];         }      //cell.tag = indexPath.row*10;      Uebungsblaetter *uebungCell = [uebungsblattArray objectAtIndex:indexPath.row];      cell.tag = indexPath.row*10;      cell.textLabel.text = [self getFileNameOutOf:uebungCell.url];      cell.textLabel.textColor = [UIColor grayColor];      cell.selectionStyle = UITableViewCellSelectionStyleNone;      UIButton *dl = [UIButton buttonWithType:UIButtonTypeCustom];      dl.tag = indexPath.row*10;      [dl setBackgroundImage:[UIImage imageNamed:@"downloadButton.png"] forState:UIControlStateNormal];      [dl setBackgroundImage:[UIImage imageNamed:@"downloadButtonH.png"] forState:UIControlStateHighlighted];      [dl setFrame:CGRectMake(230.0, (cell.frame.size.height-28)/2, 28, 28)];      [dl addTarget:self action:@selector(downloadFileWhenPressedButton:) forControlEvents:UIControlEventTouchUpInside];      [cell.contentView addSubview:dl];      UIProgressView *dlProgress = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault];      dlProgress.frame = CGRectMake(cell.frame.size.width-150, 17, 50, 9);      dlProgress.tag =indexPath.row*10+1;      dlProgress.progress = 0.0;      [cell.contentView addSubview:dlProgress];      [dlProgress setHidden:YES];           return cell;  }    //download methods  - (void)downloadFileWhenPressedButton:(UIButton*)sender{      sender.hidden = YES;      dlIndex = sender.tag/10;      Uebungsblaetter *selectedUB = [uebungsblattArray objectAtIndex:dlIndex];      NSURL *theUrl = [NSURL URLWithString:selectedUB.url];      NSURLRequest *req=[NSURLRequest requestWithURL:theUrl cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:120];      dlCell = (UITableViewCell *)[[sender superview]superview];      currDlProgress = (UIProgressView* )[dlCell.contentView viewWithTag:dlIndex*10+1];      currDlProgress.hidden = NO;      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);      dlFilePath = [NSString stringWithFormat:@"%@/%@_%@", [paths objectAtIndex:0],self.courseLable.text,[self getFileNameOutOf:selectedUB.url]];      NSURLConnection *con=[[NSURLConnection alloc] initWithRequest:req delegate:self startImmediately:YES];      if (con) {          myWebData = [NSMutableData data];      }    }    - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{      UIApplication* app = [UIApplication sharedApplication];      app.networkActivityIndicatorVisible = YES;      currDlProgress.progress = 0;      _totalFileSize = response.expectedContentLength;      NSLog(@"%@",@"connection established");      [myWebData setLength: 0];        }    - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {      _receivedDataBytes += [data length];      currDlProgress.progress = _receivedDataBytes / (float)_totalFileSize;        NSLog(@"%@",@"connection receiving data");      [myWebData appendData:data];  }    - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {      NSLog(@"%@",@"connection failed");      //  [AlertViewHandler showAlertWithErrorMessage:@"Sorry, there is no network connection. Please check your network and try again."];      //  [self parserDidEndDocument:nil];  }    - (void)connectionDidFinishLoading:(NSURLConnection *)connection {      UIApplication* app = [UIApplication sharedApplication];      app.networkActivityIndicatorVisible = NO;      [UIView beginAnimations:nil context:nil];      [UIView setAnimationDuration:0.35];      [currDlProgress setAlpha:0];      [UIView commitAnimations];      [myWebData writeToFile:dlFilePath atomically:YES];      Uebungsblaetter *loadedUB = [uebungsblattArray objectAtIndex:dlIndex];      loadedUB.downloaded = [NSNumber numberWithBool:YES];      [courseTable reloadData];  }  

Would be nice if somebody has a clue or a nice code example

source: stackoverflow.com