Swift - add element to TableView data array

Question

I have a problem where elements are not being added to my TableView-array.

My set up is quite complex..

I have a popUpView and in there is a dropDownButton with a dropDownTableView.

Here is my "DropDown.file" :

    class dropDownView: UIView, UITableViewDelegate, UITableViewDataSource  {

    var dropDownOptions = [String]()

    var tableView = UITableView()

    var delegate : dropDownProtocol!

    override init(frame: CGRect) {
        super.init(frame: frame)

        tableView.backgroundColor = UIColor.darkGray
        self.backgroundColor = UIColor.darkGray


        tableView.delegate = self
        tableView.dataSource = self

        tableView.translatesAutoresizingMaskIntoConstraints = false

        self.addSubview(tableView)

        tableView.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
        tableView.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
        tableView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
        tableView.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true

    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

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

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

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = UITableViewCell()

        cell.textLabel?.text = dropDownOptions[indexPath.row]
        cell.backgroundColor = UIColor.lightGray
        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        self.delegate.dropDownPressed(string: dropDownOptions[indexPath.row])
        self.tableView.deselectRow(at: indexPath, animated: true)
    }

}


protocol dropDownProtocol {
    func dropDownPressed(string : String)
}

//MARK: DropDownButton

class dropDownBtn: UIButton, dropDownProtocol {

    func dropDownPressed(string: String) {
        self.setTitle(string, for: .normal)
        self.dismissDropDown()
    }

    var dropView = dropDownView()

    var height = NSLayoutConstraint()


    override init(frame: CGRect) {
        super.init(frame: frame)

        self.backgroundColor = UIColor.lightGray

        dropView = dropDownView.init(frame: CGRect.init(x: 0, y: 0, width: 0, height: 0))
        dropView.delegate = self
        dropView.translatesAutoresizingMaskIntoConstraints = false
    }

    override func didMoveToSuperview() {
        self.superview?.addSubview(dropView)
        self.superview?.bringSubviewToFront(dropView)
        dropView.topAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
        dropView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
        dropView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
        height = dropView.heightAnchor.constraint(equalToConstant: 0)
    }

    var isOpen = false
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if isOpen == false {

            isOpen = true

            NSLayoutConstraint.deactivate([self.height])

            if self.dropView.tableView.contentSize.height > 150 {
                self.height.constant = 150
            } else {
                self.height.constant = self.dropView.tableView.contentSize.height
            }


            NSLayoutConstraint.activate([self.height])

            UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
                self.dropView.layoutIfNeeded()
                self.dropView.center.y += self.dropView.frame.height / 2
            }, completion: nil)

        } else {
            isOpen = false

            NSLayoutConstraint.deactivate([self.height])
            self.height.constant = 0
            NSLayoutConstraint.activate([self.height])
            UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
                self.dropView.center.y -= self.dropView.frame.height / 2
                self.dropView.layoutIfNeeded()
            }, completion: nil)

        }
    }

    func dismissDropDown() {
        isOpen = false
        NSLayoutConstraint.deactivate([self.height])
        self.height.constant = 0
        NSLayoutConstraint.activate([self.height])
        UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
            self.dropView.center.y -= self.dropView.frame.height / 2
            self.dropView.layoutIfNeeded()
        }, completion: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

So what I do is I create the dropDownButton inside my ViewController and constrain it if the popUpView appears like this and also add the first element:

// constrain dropDownbutton
    dropDownButton.centerXAnchor.constraint(equalTo: self.popUpView.centerXAnchor).isActive = true
    dropDownButton.centerYAnchor.constraint(equalTo: self.popUpView.centerYAnchor).isActive = true
    dropDownButton.widthAnchor.constraint(equalToConstant: 170).isActive = true
    dropDownButton.heightAnchor.constraint(equalToConstant: 40).isActive = true

    //Set the drop down menu's options
    dropDownButton.dropView.dropDownOptions.append("Main Wishlist")

So far so good, that is working just fine. My problem is that I would like to be able to add elements to dropView.dropDownOptions from another func. Right now if I add an element from the other function it only adds the elements to the array until I let the popUpView appear for the first time. As soon as I let it appear and disappear again and try to add another element again it is not working and it just shows the old array without the new added element.

I tried to explain it as easy as possible. If anything is unclear just let me know and I will try to elaborate on that :)

You need to reload the data of tableview after appending elements to array. — Nexus
– Nexus, Commented Dec 15, 2019 at 4:33

Nanda Julianda Akbar · Accepted Answer · 2019-12-15 03:24:15Z

1

The simple approach is reload the table view from the main thread whenever new data appended to the array.

So, in your case, you can simply add a public method in dropDownView class to append the data. here's the example:

func append(data: String) {
   dropDownOptions.append(data)

   DispatchQueue.async.main { [weak self] in 
     self?.tableView.reloadData()
   }
}

answered Dec 15, 2019 at 3:24

Nanda Julianda Akbar

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1 Comment

Chris Over a year ago

thanks for you answer, I did not even need an extra method. I just reload the tableView after appending like @Nexus suggested :)

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