set UITableView.separatorLine to 2px and with different colors each pixel

tableCellView.m

//...

- (void)drawRect:(CGRect)rect{
  CGContextRef context = UIGraphicsGetCurrentContext();
  
  [[UIColor colorWithHexString:@"FEFFFE"] setStroke];
  
  CGContextSetLineWidth(context, 1);
  CGContextBeginPath(context);
  CGContextMoveToPoint(context, 0, 0.5);
  CGContextAddLineToPoint(context, CGRectGetMaxX(rect), 0.5);
  
  CGContextStrokePath(context);
}

//...

tableViewController.m

//...

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
  static NSString *CellIdentifier = @"CellIdentifier";
  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
  
  // Configure the cell...
  // do whatever you need to do.
  
  if (indexPath.row == [self.dataArray count] - 1) {
    // last cell
    cell.layer.masksToBounds = NO;
    cell.layer.shadowOpacity = 1.0;
    cell.layer.shadowOffset = CGSizeMake(0, 1);
    cell.layer.shadowColor = [UIColor colorWithHexString:@"FEFFFE"].CGColor;
    cell.layer.shadowRadius = 0;
  }else {
    cell.layer.masksToBounds = YES;
  }
  
  return cell;
}

//...

UITableView_SeparatorLine.md

Question

How to implement a UITableView with a separator line like this:

Usually, you can only set the separatorLine property of a UITableView with to single line or single line etched. Sometimes, it is not enough. So, how to implement a separator line like this?

Answer

First of all, we must know a doubly separator line is what we want our user to see. It doesn't matter if the line is composed with a single separator line and a fake line within the cell below. So this is the solution.

Solution

1. Set the separator line to single line and color to the dark color #D6D6CE
2. Add a white line to the cell at the top(see tableCellView.m)
3. Add a shadow to the tableview to make the last line looks like a doubly line (see tableViewController.m)

Let's take a look at the source code.

A very important NOTE

Take a look at the - drawRect: method, we added 0.5 to the drawing position. I don't why but if do not added this, the line will look like blurred. But the shadow is fine.

What to do if I don't need this drawing for some specific cells ?