How do I create a custom UITableViewCell class in Swift?

Question

I'm trying to follow along the following Using Auto Layout in UITableView for dynamic cell layouts & variable row heights top answer in Swift but for the IOS 7 version to mitigate some bugs in the IOS 8.

Right now, my custom cell class is:

class PostCell: UITableViewCell {

    @IBOutlet var name: UILabel!
    @IBOutlet var timestamp: UILabel!
    @IBOutlet var postBody: UILabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}

In my Storyboard I set my custom class as the class for the cell. I don't know if I have to use my reuseIdentifier anywhere. I don't know how to get that working in the next piece of code.

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

    var cell = PostCell()

    var post = self.posts[indexPath.row]

    cell.name.text = post.name
    cell.timestamp.text = post.timestamp
    cell.postBody.text = post.body

    cell.setNeedsUpdateConstraints()
    cell.updateConstraintsIfNeeded()

    cell.bounds = CGRectMake(0.0, 0.0, CGRectGetWidth(feed.bounds), CGRectGetHeight(cell.bounds))

    cell.setNeedsLayout()
    cell.layoutIfNeeded()

    var height = cell.contentView.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize).height

    height += 1.0

    return height
}

I thought that would work, but when I call cell.name.text = post.name, I get an EXC_BAD_INSTRUCTION. I'm guessing the cell isn't properly hooked up to the storyboard somehow or something. How do I fix this?

matt · Accepted Answer · 2015-02-01 00:46:44Z

1

The problem is that you don't understand how nibs work. You have set up your PostCell to be configured when it is loaded from its nib:

class PostCell: UITableViewCell {
    @IBOutlet var name: UILabel!
}

So that means that name is nil - until this cell is instantiated from the nib, at which time the outlet will be hooked up. But then later you say:

var cell = PostCell()

But that is the wrong PostCell! You didn't load it from the nib; you just made one out of whole cloth. So since there was no nib-loading, the outlet (as you rightly suspect) was naturally never connected, and so cell.name is nil.

So the solution is: do not make one out of whole cloth. Load it from the nib.

answered Feb 1, 2015 at 0:46

matt

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7 Comments

David Over a year ago

Honestly, I don't even know what a nib is. How would I load it from the nib?

matt Over a year ago

Tell me the name of the nib. - Or is it configured in the storyboard?

David Over a year ago

I set the identifier for the cell to be "gatePost". Yes it is made in the Storyboard

matt Over a year ago

Okay, so try this: instead of saying PostCell(), ask the tableView to dequeue you a cell with the "gatePost" identifier. It will get it from the nib (the one in the storyboard) and so its outlets should be hooked up when it comes to you!

matt Over a year ago

It isn't the way I would have done it; I would have used a .xib file. But now you're kind of stuck. Anyhow, just try it for now. You can change architectures later if you want; right now let's just try to get you a cell.

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