Cell Resize Example

// resizing table view cells on data change

import UIKit

struct MyDataStruct {
    var title: String = ""
    var tapCount: Int = 0
}

class SimpleCell: UITableViewCell {

    var callback: ((Int, UITableViewCell)->())?

    let theLabel: UILabel = {
        let v = UILabel()
        v.numberOfLines = 0
        v.backgroundColor = .yellow
        return v
    }()

    let btn: UIButton = {
        let v = UIButton()
        v.backgroundColor = .systemRed
        return v
    }()

    private var title: String = ""
    private var tapCount: Int = 0

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        commonInit()
    }
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    func setData(_ d: MyDataStruct) -> Void {
        title = d.title
        tapCount = d.tapCount
        theLabel.text = title + " Taps: \(tapCount)"
    }
    func commonInit() -> Void {
        [theLabel, btn].forEach { v in
            v.translatesAutoresizingMaskIntoConstraints = false
            contentView.addSubview(v)
        }
        let g = contentView.layoutMarginsGuide

        NSLayoutConstraint.activate([

            theLabel.topAnchor.constraint(equalTo: g.topAnchor),
            theLabel.leadingAnchor.constraint(equalTo: g.leadingAnchor),
            theLabel.bottomAnchor.constraint(lessThanOrEqualTo: g.bottomAnchor),

            btn.topAnchor.constraint(equalTo: g.topAnchor),
            btn.trailingAnchor.constraint(equalTo: g.trailingAnchor),
            btn.bottomAnchor.constraint(lessThanOrEqualTo: g.bottomAnchor),
            btn.widthAnchor.constraint(equalToConstant: 100.0),

            btn.leadingAnchor.constraint(equalTo: theLabel.trailingAnchor, constant: 8.0),
        ])

        btn.setTitle("Tap Me", for: [])
        btn.addTarget(self, action: #selector(gotTap(_:)), for: .touchUpInside)
    }

    @objc func gotTap(_ sender: Any) {
        tapCount += 1
        theLabel.text = title + " Taps: \(tapCount)"
        callback?(tapCount, self)
    }

}

class RowSizingTableViewController: UITableViewController {

    var myData: [MyDataStruct] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        for i in 0..<20 {
            let t = MyDataStruct(title: "Row: \(i)", tapCount: 0)
            myData.append(t)
        }

        tableView.register(SimpleCell.self, forCellReuseIdentifier: "cell")
    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return myData.count
    }

    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        print(#function, indexPath, myData[indexPath.row])
        return CGFloat(60 + (myData[indexPath.row].tapCount * 20))
    }

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

        cell.setData(myData[indexPath.row])

        cell.callback = { [weak self] n, c in
            guard let self = self,
                  let pth = self.tableView.indexPath(for: c)
            else { return }

            // update data
            self.myData[pth.row].tapCount = n

            // both
            //  beginUpdates() / endUpdates()
            // and
            //  performBatchUpdates()
            // seem to work fine...

            self.tableView.beginUpdates()
            self.tableView.endUpdates()

            //self.tableView.performBatchUpdates(nil, completion: nil)

        }

        return cell
    }

}