My TableView's not changed after reload data - swift

Question

I wrote a class that let me create multiple tableView simply. When I call this class for the first time, everything work well. But when I change some data, and reload the table, nothing changed.
Sample code:
class TestViewController: UIViewController {
var arrData = ["a","b","c"]
var myTableView: MyTableView?
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
myTableView = MyTableView(table: tableView, data: arrData)
}
#IBAction func buttonTapped(_ sender: UIButton) {
arrData = ["d","e","f"]
myTableView!.tableView.reloadData() //=> Not change anything
}
}
class MyTableView: NSObject, UITableViewDataSource {
var tableView: UITableView
var data: Array<String>
init(table: UITableView, data: Array<String>) {
self.data = data
self.tableView = table
super.init()
self.tableView.dataSource = self
self.tableView.register(MyTableViewCell.self, forCellReuseIdentifier: "myCell")
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.data.count
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCell(withIdentifier: "myCell", for: indexPath) as! MyTableViewCell
cell.textLabel!.text = self.data[indexPath.row]
return cell
}
}
class MyTableViewCell : UITableViewCell {
//something here
}
When the view was loaded, the table has 3 rows: a,b,c. When I tap the button, nothing changed (expected: d,e,f)
Please help me!

Answer 1

Swift arrays are copied by value so the line self.data = data will take a copy of your array. Later changing the array contents of the source will not be reflected in the copy in your MyTableView.
You'll need to pass the array over again and take a second copy to update the table, e.g. write a method in MyTableView similar to the following:-
func setNewValues(data: Array<String>)
{
self.data = data
self.tableView.reloadData()
}
and call that from your buttonTapped function, i.e.:
#IBAction func buttonTapped(_ sender: UIButton) {
arrData = ["d","e","f"]
myTableView!.setNewValues(data: arrData)
}
Be careful with the force-unwrapped myTableView though - I'd replace that '!' with '?'.