How to Set UITableViewCellStyleSubtitle and dequeueReusableCell in Swift?

I'd like a UITableView with subtitle-style cells that use dequeueReusableCellWithIdentifier.

My original Objective-C code was:

static NSString *reuseIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];
if(!cell)
{
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:reuseIdentifier];
}

After searching the few UITableView questions here already on SO, I thought to write it in Swift like so:

tableView.registerClass(UITableViewCell.classForCoder(), forCellReuseIdentifier: "Cell")

let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell

But that doesn't let me say I want a subtitle style. So I tried this:

var cell :UITableViewCell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "Cell")

Which gives me a subtitle cell, but it doesn't let me dequeueReusableCellWithIdentifier.

I've researched some more and looked at this video tutorial, but he creates a separate subclass of UITableViewCell which I assume is unnecessary as I accomplished this same effect previously in Obj-C.

Any ideas? Thanks.

Solution 1:

Keep in mind that UITableView is defined as an optional in the function, which means your initial cell declaration needs to check for the optional in the property. Also, the returned queued cell is also optional, so ensure you make an optional cast to UITableViewCell. Afterwards, we can force unwrap because we know we have a cell.

var cell:UITableViewCell? = 
tableView?.dequeueReusableCellWithIdentifier(reuseIdentifier) as? UITableViewCell
if (cell == nil)
{
   cell = UITableViewCell(style: UITableViewCellStyle.Subtitle, 
                reuseIdentifier: reuseIdentifier)
}
// At this point, we definitely have a cell -- either dequeued or newly created,
// so let's force unwrap the optional into a UITableViewCell
cell!.detailTextLabel.text = "some text"

return cell

Solution 2:

If you'd rather avoid optionality, you can make a subclass of UITableViewCell that looks something like this:

class SubtitleTableViewCell: UITableViewCell {

    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: .subtitle, reuseIdentifier: reuseIdentifier)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

Then register it using:

override func viewDidLoad() {
    super.viewDidLoad()
    self.tableView.register(SubtitleTableViewCell.self, forCellReuseIdentifier: reuseIdentifier)
}

This allows your cell customization code to be really nice:

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifier, for: indexPath)

    cell.textLabel?.text = "foo"
    cell.detailTextLabel?.text = "bar"

    return cell
}

Solution 3:

Basically the same as other answers, but I get around dealing with nasty optionals (you can't return nil from -tableView:cellForRow:atIndexPath: in Swift) by using a computed variable:

Swift 3

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell: UITableViewCell = {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "UITableViewCell") else {
            // Never fails:
            return UITableViewCell(style: UITableViewCellStyle.value1, reuseIdentifier: "UITableViewCell")
        }
        return cell
    }()

    // (cell is non-optional; no need to use ?. or !)

    // Configure your cell:
    cell.textLabel?.text       = "Key"
    cell.detailTextLabel?.text = "Value"

    return cell
}

Edit:

Actually, it would be better to dequeue the cell using: tableView.dequeueReusableCell(withIdentifier:for:) instead.

This later variant of the function automatically instantiates a new cell if no one is available for reusing (exactly what my code does explicitly above), and therefore never returns nil.

Solution 4:

Just building upon memmons' answer by cleaning it up Swift 2 style...

let cell = tableView.dequeueReusableCellWithIdentifier(reuseIdentifier) ?? UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: reuseIdentifier)

cell.detailTextLabel?.text = "some text"

return cell

Swift 3:

let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) ?? UITableViewCell(style: .subtitle, reuseIdentifier: cellIdentifier)

cell.detailTextLabel?.text = ""

return cell

Solution 5:

Since tableView.dequeueReusableCell(withIdentifier:, for:) return a non-nil cell, the if cell == nil check is always be false. But I found a solution, to makes default style cell become what style(value1, value2 or subtitle) you want, because default style cell's detailTextLabel is nil, so check the detailTextLabel if it's nil, then create new style cell, and give it to dequeue cell, like:

Swift 3:

var cell = tableView.dequeueReusableCell(withIdentifier: yourCellReuseIdentifier, for: indexPath)

if cell.detailTextLabel == nil {
    cell = UITableViewCell(style: .value1, reuseIdentifier: repeatCellReuseIdentifier)
}

cell.textLabel?.text = "Title"
cell.detailTextLabel?.text = "Detail"

return cell

That's works for me.

Hope it's help.