UILongPressGestureRecognizer *lpHandler = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressHandler:)];
lpHandler.minimumPressDuration = 0.5; //seconds
lpHandler.delegate = self;
[uiTableView addGestureRecognizer:lpHandler];
[lpHandler release];
···
-(void)longPressHandler:(UILongPressGestureRecognizer *)gestureRecognizer
{
    CGPoint p = [gestureRecognizer locationInView:self.tableView];	
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:p];
    if (indexPath == nil)
        NSLog(@"long press on table view");
    else
        NSLog(@"long press on row %d", indexPath.row);
}

Detect long touches on any UIView

Long Touch Recognizer

Objective C