UITableViewCell layout not updating until cell is reused

Question

I have a UITableView that I fill with autosizing cells. UITableView setup is fairly simple:

    tableView.estimatedRowHeight = 70
    tableView.rowHeight = UITableViewAutomaticDimension

Exactly like Apple recommends here: https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/AutolayoutPG/WorkingwithSelf-SizingTableViewCells.html

To enable self-sizing table view cells, you must set the table view’s rowHeight property to UITableViewAutomaticDimension. You must also assign a value to the estimatedRowHeight property. As soon as both of these properties are set, the system uses Auto Layout to calculate the row’s actual height.

When configuring a cell I also disable/enable some constraints to achieve the needed look. That’s where things get interesting. Cell layout is not updated until the cell is reused. Literally. You can call layoutIfNeeded(), setNeedsLayout(), layoutSubviews() or any other method there is, there is no way you will force the cell to update its layout.

All other aspects work pretty good: labels do change their text, you hide/unhide the views, but layout is stuck until the cell is reused.

Question: what causes it and how to avoid this behavior?

score 7 · Answer 1 · answered Jun 15 '18 at 09:52

I had your problem too. Instead of remove

tableView.estimatedRowHeight = 70

I just added a layoutIfNeeded at the end of the cellForRow method, just before return the cell itself:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "identifier", for: indexPath) as? MyCustomCell
    ...
    cell?.layoutIfNeeded()
    return cell!
}

Result: the cell layout is perfect always, the first time and every after reuse.

score 6 · Answer 2 · answered Nov 30 '20 at 13:52

6

Unfortunately, none of the provided answers/comments worked out for me. I always ended up with an initially incorrect layout. Only after reusing the cell, or calling reloadData() (on the table view) it was displayed correctly.

The following was the only thing, that worked for me in the end. I'm not a big fan of such hacks, but after spending about half a day on this seemingly very simple layout issue, I just gave up and went with it. >.<

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    DispatchQueue.main.async {
        self.tableView.reloadData()
    }
}

Alternatively you could also call reloadData it in viewDidAppear (without the DispatchQueue hack), but then you can clearly see the "jump" when the layout jumps from "incorrect" to "correct".

Anyway, just wanted to share my experience and hope this helps someone else. Cheers!

answered Nov 30 '20 at 13:52

d4Rk

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viewWillAppear is always called on the main thread. – Bryan Bryce Nov 11 '21 at 03:29
It's not about the thread, it's about the async "delay". – d4Rk Nov 11 '21 at 05:18
After scouring SO, Apple forums and random places on the internet, this is the only thing that actually fixed it for me. – JarWarren Feb 10 '22 at 20:07
@JarWarren Your comment had me excited.. but unfortunately I am still getting the same issue even with calling reloaddata in viewwillappear – JCutting8 May 08 '22 at 21:35
1

Nice one, worked for me. I feel gross and need a shower, but after hacking at it for a long... time its the only thing that worked for me too. Thanks for the share! – mobob May 16 '23 at 18:27

rajneesh biswal · Answer 3 · 2022-02-27T01:25:43.587

Cell layout is not updated until cell is reused

If you want tableview to reflect changed cell layout.

After changing the cell Layout redraw the table view

        tableView.beginUpdates()
        tableView.setNeedsDisplay()
        tableView.endUpdates()

For instance:

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        guard let cell = tableView.cellForRow(at: indexPath) as? CustomCell else { return }
        cell.collapseDescriptionLabel()
        
        // redraw the tableView
        tableView.beginUpdates()
        tableView.setNeedsDisplay()
        tableView.endUpdates()
    }

score 2 · Answer 4 · answered Nov 10 '16 at 18:07

In my case, the issue was caused by estimatedRowHeight.

Simply removing this line

tableView.estimatedRowHeight = 70

fixed my problems. Cell properly updated its layout and it almost fixed my issues.

But, most likely, you’re going to get another trouble, with your cell’s height being set to 43.5 points. You log will also be filled with auto layout errors, that will include a line like this

<NSLayoutConstraint:0x600000097570 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x7fd4ee511d20.height == 43.5   (active)>

Apparently, if you won’t provide estimatedRowHeight, table view puts a 43.5 points height constraint on your cell’s content view, and if your cell’s “internal” height will not match (and probability of that is 99.99%), then it’s going to put errors in log.

How to avoid that error? I don’t know yet. I post a question about that, and as soon as I find an answer, I will provide a link in this question.

score 1 · Answer 5 · answered Jan 13 '22 at 03:51

You don't need to use layoutIfNeeded(), setNeedsLayout(), and layoutSubviews() to force the layout. You can use tableView.beginUpdates() and tableView.endUpdates().

For instance:

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let cell = tableView.cellForRow(at: indexPath)
        tableView.beginUpdates()
        cell.heightConstraint.constant = 50
        tableView.endUpdates()
}

UITableViewCell layout not updating until cell is reused

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