iosswiftuitableviewuitableviewautomaticdimension

Self sizing tableview inside self sizing tableview cell


Let's say I have hierarchy like this:

*TableViewCell
**TableView
***TableViewCell

and all of them should be resizable. Did someone face this kind of problem? In past I've used many workarounds like systemLayoutSizeFitting or precalculation of height in heightForRowAt, but it always breaks some constraints, because TableViewCell has height constraint equal to estimated row height and there appear some kinds of magic behavior. Any ways to make this live?

Current workaround:

class SportCenterReviewsTableCell: UITableViewCell, MVVMView {
    var tableView: SelfSizedTableView = {
        let view = SelfSizedTableView(frame: .zero)
        view.clipsToBounds = true
        view.tableFooterView = UIView()
        view.separatorStyle = .none
        view.isScrollEnabled = false
        view.showsVerticalScrollIndicator = false
        view.estimatedRowHeight = 0
        if #available(iOS 11.0, *) {
            view.contentInsetAdjustmentBehavior = .never
        } else {
            // Fallback on earlier versions
        }

        return view
    }()

    private func markup() {
        contentView.addSubview(tableView)
        tableView.delegate = self
        tableView.dataSource = self
        tableView.register(ReviewsTableViewCell.self, forCellReuseIdentifier: "Cell")
        tableView.snp.makeConstraints() { make in
            make.top.equalTo(seeAllButton.snp.bottom).offset(12)
            make.left.equalTo(contentView.snp.left)
            make.right.equalTo(contentView.snp.right)
            make.bottom.lessThanOrEqualTo(contentView.snp.bottom)
        }
    }


    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! ReviewsTableViewCell

        cell.viewModel = viewModel.cellViewModels[indexPath.row]

        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell") as! ReviewsTableViewCell

        cell.viewModel = viewModel.cellViewModels[indexPath.row]
        cell.setNeedsLayout()
        cell.layoutIfNeeded()
        let size = cell.contentView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize, withHorizontalFittingPriority: .defaultHigh, verticalFittingPriority: .defaultLow)

        return size.height
    }
}

Self sizing tableView class:

class SelfSizedTableView: UITableView {
    override func reloadData() {
        super.reloadData()
        self.invalidateIntrinsicContentSize()
        self.layoutIfNeeded()
    }

    override var intrinsicContentSize: CGSize {
        self.setNeedsLayout()
        self.layoutIfNeeded()
        return contentSize
    }
}


Solution

  • This is actually not an answer to the question, but just an explanation.
    (Wrote here because of the character count limitation for the comments).

    The thing is that you're trying to insert a vertically scrollable view inside another vertically scrollable view. If you don't disable the nested tableview's scroll ability, you will have a glitch while scrolling, because the system wouldn't know to whom pass the scroll event (to the nested tableview, or to the parent tableview). So in our case, you'll have to disable the "scrollable" property for the nested tableviews, hence you'll have to set the height of the nested tableview to be equal to its content size. But this way you will lose the advantages of tableview (i.e. cell reusing advantage) and it will be the same as using an actual UIScrollView. But, on the other hand, as you'll have to set the height to be equal to its content size, then there is no reason to use UIScrollView at all, you can add your nested cells to a UIStackView, and you tableview will have this hierarchy:

    *TableView
    **TableViewCell
    ***StackView
    ****Items
    ****Items
    ****Items
    ****Items
    

    But again, the right solution is using multi-sectional tableview. Let your cells be section headers of the tableview, and let inner cells be the rows of the tableview.