iOS tableView with two special rows of headers

Question

Using swift for iOS, here is my cellforRow method

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 
 switch indexPath.section {
 case 0: // Cover Image
 guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifierCover) as? AddBlogCoverTableViewCell else { return UITableViewCell() }
 cell.layer.backgroundColor = UIColor.clear.cgColor
 cell.selectionStyle = .none
 cell.indexPath = indexPath
 cell.delegate = self
 cell.titleTextField.delegate = self
 cell.coverImageView.image = coverImage
 cell.titleTextField.placeholder = "Title"
 cell.titleTextField?.text = articleName ?? ""
 cell.setBorder(of: 0.7, ofColor: UIColor.lightGray.cgColor)
 return cell
 case 1: // rest story
 guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) as? AddBlogTableViewCell else { return UITableViewCell() }
 cell.layer.backgroundColor = UIColor.clear.cgColor
 cell.selectionStyle = .none
 cell.indexPath = indexPath
 cell.delegate = self
 cell.captionTextView.delegate = self
 cell.captionTextView.tag = indexPath.row
 cell.tag = indexPath.section
 cell.media = cards?[indexPath.row].media
 cell.captionTextView.text = cards?[indexPath.row].caption ?? ""
 showLocationSuggestions(at: indexPath, in: cell)
 cell.poi = cards?[indexPath.row].poi
 return cell
 default:
 return UITableViewCell()
 }
 return UITableViewCell()
}

How should I avoid repeating the code that I have to provide to the cell in all cases of switch?

Answer 1

Defensive programming (never force unwrap, no forced cast, ...) is good and important to handle "runtime problems" gracefully: Unexpected user input, failed network connections, I/O errors, and many more.

But programming errors are a different category. Example 1: If

tableView.dequeueReusableCell(withIdentifier: cellIdentifierCover)

fails, or does not return a AddBlogCoverTableViewCell, then you did not configure the table view correctly in the Storyboard. Such cases should be detected during development. Therefore it is better to abort with a runtime error instead of "hiding" the problem and returning a plain UITableViewCell. This is a valid use-case for a forced cast:

 let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifierCover) as! AddBlogCoverTableViewCell

or better:

let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifierCover, for: indexPath) as! AddBlogCoverTableViewCell

Example 2: Your table view has 2 sections, so indexPath.section must be 0 or 1, every other value would be a programming error. Again, fail early instead of hiding the problem:

switch indexPath.section {
case 0:
 // do something ...
case 1:
 // do something ...
default:
 fatalError("Unexpected section \(indexPath.section)")
}

Note also that your final

return UITableViewCell()

is never be executed.

---

Now for possible simplifications. Both cell classes have some properties in common, these can be defined in a common superclass:

class AddBlogCommonCell : UITableViewCell {
 var indexPath: IndexPath!
 var delegate: UITableViewController!
 // ...
}
class AddBlogCoverTableViewCell : AddBlogCommonCell {
 // ...
}
class AddBlogTableViewCell : AddBlogCommonCell {
 // ...
}

Then you can configure the specific properties inside the switch statement, and the shared properties outside the switch statement, thereby avoiding the code repetition:

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
 let cell: AddBlogCommonCell
 switch indexPath.section {
 case 0:
 let coverCell = tableView.dequeueReusableCell(withIdentifier: cellIdentifierCover) as! AddBlogCoverTableViewCell
 coverCell.titleTextField.delegate = self
 coverCell.coverImageView.image = coverImage
 // ...
 cell = coverCell
 case 1:
 let storyCell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) as! AddBlogTableViewCell
 storyCell.captionTextView.delegate = self
 storyCell.captionTextView.tag = indexPath.row
 // ...
 cell = storyCell
 default:
 fatalError("Unexpected section \(indexPath.section)")
 }
 // AddBlogCommonCell properties:
 cell.delegate = self
 cell.indexPath = indexPath
 // ...
 // UITableViewCell properties:
 cell.layer.backgroundColor = UIColor.clear.cgColor
 cell.selectionStyle = .none
 // ...
 return cell
}

• saurabh: Thanks a lot for the detailed answer. It's very helpful. But I am using xib, and its a bit tricky to subclass cells using xib.
• trapper: Also don't switch on case 0,1 name your constants: CoverSection, StorySection

Answer 2

The easiest and the fastest way that I see is to use a configuration closure.

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
 let configureCell = { (cell: MyGenericTableViewCell) in
 // Generic configurartion
 }
 switch indexPath.section {
 case 0: // Cover Image
 guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifierCover) as? AddBlogCoverTableViewCell else { return UITableViewCell() }
 configureCell(cell)
 // Perform cell-specific config
 return cell
 case 1: // rest story
 guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) as? AddBlogTableViewCell else { return UITableViewCell() }
 configureCell(cell)
 // Perform cell-specific config
 return cell
 default:
 return UITableViewCell()
 }
 return UITableViewCell()
}

Also, some part of your configuration, such as:

cell.layer.backgroundColor = UIColor.clear.cgColor
cell.selectionStyle = .none

can be put inside initialization methods of the cells.