How to change height of UITableViewCell when constraint changes?

Question

My question is related to this one: How to change height Constraint of UIView in UitableviewCell when using UITableViewAutomaticDimension

The solution there does not seem to be working for me.

In the image above i have a simple cell. On tap of cell, i want to change the constraint of the redView to be larger. This should then automatically change the height of the cell.

I already have the height constraint of the cell set to an @IBOutlet and i think i am correctly changing the size of the cell, but it is not working.

Here is my sample app that is not working. Any help? SampleApp - for Xcode 9.3

Answer 1

You need to set a bottom constraint to the red view so auto-layout can stretch the cell after setting the constant value

extension ViewController: UITableViewDataSource, UITableViewDelegate {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "c", for: indexPath) as! customcell
        configure(cell: cell, indexPath: indexPath)
        cell.redview.backgroundColor = .red
        cell.selectionStyle = .none
        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let cell = tableView.cellForRow(at: indexPath) as! customcell
        cell.constraint.constant = data[indexPath.row] == "contracted"  ? 30 : 200
        data[indexPath.row] = data[indexPath.row] == "contracted" ? "expanded" : "contracted"
        tableView.reloadData()
    }

    func configure(cell: customcell, indexPath: IndexPath) {
        let data = self.data[indexPath.row]
        if data == "expanded" {
            cell.constraint.constant = 200
        } else {
            cell.constraint.constant = 30
        }

        cell.layoutIfNeeded()
    }
}

Answer 2

Calling the below will recalculate the heights.

[tableView beginUpdates];
[tableView endUpdates];