如何在表格视图单元格中以编程方式添加视图，Swift

Question

Please help. I want to create table view cell content absolutely programmatically. But it's not wroking ( Where I'm wrong? My code:

import Foundation
import UIKit

class FiltersMenuCell: UITableViewCell {
    var customFilters = [SearchRequestRestModelItem]()
    var filtersCounters: NSDictionary? = nil
    var isMyFilters = true

    @IBOutlet weak var mainView: UIView!

    func initFilters() {
        let customFiltersSize = customFilters.count
        var previousFilterNameLabel: UILabel? = nil
        for index in 0..<customFiltersSize {
            let filterNameLabel = UILabel()
            filterNameLabel.font = UIFont(name: Constants.regularFontName, size: 16)
            filterNameLabel.numberOfLines = 1
            filterNameLabel.lineBreakMode = .byTruncatingTail
            filterNameLabel.textColor = UIColor.black
            filterNameLabel.text = "My filters".localized

            mainView.addSubview(filterNameLabel)

            filterNameLabel.leadingAnchor.constraint(equalTo: mainView.leadingAnchor, constant: 8).isActive = true

            filterNameLabel.trailingAnchor.constraint(equalTo: mainView.trailingAnchor, constant: 8).isActive = true
            filterNameLabel.topAnchor.constraint(equalTo: mainView.topAnchor, constant: 8).isActive = true
            filterNameLabel.bottomAnchor.constraint(equalTo: mainView.bottomAnchor, constant: 8).isActive = true 
            ...

Cell intialization:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
            let cell = tableView.dequeueReusableCell(withIdentifier: Constants.filtersMenuCell) as! FiltersMenuCell
            cell.isMyFilters = indexPath.row == 4

            cell.customFilters = cell.isMyFilters ? presenter!.getMyFilters(allCustomFilters: customFilters)
                    : presenter!.getSharedFilters(allCustomFilters: customFilters)
            cell.filtersCounters = allTicketsCountModel.customFiltersCounters
            cell.initFilters()

            return cell)
    }

Why it's not working? Thank you in advance!

Answer 1

Your constraints on views are not working, so you need to add first

yourMainView.translatesAutoresizingMaskIntoConstraints = false
yourLabel.translatesAutoresizingMaskIntoConstraints = false   

// and add below code in you cellForRow AtIndexPath
DispatchQueue.main.async {
cell.setNeedsLayout()
cell.layoutIfNeeded()
}

Answer 2

Maybe your filterNameLabel constraints are not properly created. You need to set the first index filterNameLabel top constraint equal to mainView top constraint. and last index filterNameLabel bottom constraint equal to mainView bottom constraint. And other constraints is relative, that means next filterNameLabel top constraint equal to previous filterNameLabel bottom constraint. Always call layout if needed method.

On the other way if you want to take another tableView inside FiltersMenuCell, you can follow these steps:

1) Create a tableView inside FiltersMenuCell class. Initialize this closure into this class.

@IBOutlet weak var tableView: UITableView!

var tableViewContentSizeHeight: CGFloat {
    view.layoutIfNeeded()
    return tableView.contentSize.height
}

2) Create "mainView" height constraint into FiltersMenuCell class globally.

var mainView: UIView!
var heightConstraint: NSLayoutConstraint!

heightConstraint = mainView.heightAnchor.constraint(equalToConstant: 0)
heightConstraint.isActive = true

3) Update "heightConstraint" from cellForRowAt

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    if let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as? FiltersMenuCell {
        cell.reloadData()
        cell.heightConstraint.constant = cell.tableViewContentSizeHeight
        return cell
    }
    return UITableViewCell()
}