Create custom UITableView class - swift

Question

How i can to create heir of UITableView class that will contain delegate and dataSource methods? I don't want to have dataSource and delegate methods in my ViewController.

Answer 1

You need to create another class for the purpose but first let's see how the ViewController will be.
As you can see the code is sort of self explanatory, I have created a custom class called TableViewDelegate that will be set as a delegate and dataSource of the tableView.
We are passing to TableViewDelegate, the data to be shown in the tableView, and function named didSelectRow that will be called by TableViewDelegate once a row is selected.
class ViewController: UIViewController {
#IBOutlet weak var tableView: UITableView!
// data source
var data = [1, 2, 3, 4]
// delegate
var tableViewDelegate: TableViewDelegate?
override func viewDidLoad() {
super.viewDidLoad()
// creating the delegate object and passing the data
tableViewDelegate = TableViewDelegate(data: data)
// passing a function to the delegate object
tableViewDelegate?.didSelectRow = didSelectRow
// setting the delegate object to tableView
tableView.delegate = tableViewDelegate
tableView.dataSource = tableViewDelegate
}
// a function that will be called by the delegate object
// when a row is selected
func didSelectRow(dataItem: Int, cell: UITableViewCell) {
let alert = UIAlertController(title: "Info", message: "\(dataItem) was selected.", preferredStyle: .Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
presentViewController(alert, animated: true, completion: nil)
}
}
The TableViewDelegate that is in charged of everything related of UITableViewDelegate, and UITableViewDataSource protocols.
class TableViewDelegate: NSObject, UITableViewDelegate, UITableViewDataSource {
var data = [Int]()
// variable that holds a stores a function
// which return Void but accept an Int and a UITableViewCell as arguments.
var didSelectRow: ((dataItem: Int, cell: UITableViewCell) -> Void)?
init(data: [Int]) {
self.data = data
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
let text = String(data[indexPath.row])
cell.textLabel?.text = text
return cell
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let cell = tableView.cellForRowAtIndexPath(indexPath)!
let dataItem = data[indexPath.row]
if let didSelectRow = didSelectRow {
// Calling didSelectRow that was set in ViewController.
didSelectRow(dataItem: dataItem, cell: cell)
}
}
}
Result:

Answer 2

I did this to avoid a long ViewController with a UIPickerViewDelegate/DS. You can simply make a class that conforms to UITableViewDelegate and UITableViewDataSource, instantiate this object in your view controller and assign it as the dataSource and delegate of the table view. For this class to send stuff back to your ViewController, you will have to make a protocol for the VC to conform to and give the class a delegate as well.
I read that this class must inherit from NSObject as the protocols are NSObject protocols, and it throws and error if they don't.
class MyCustomTableViewDel: NSObject, UITableViewDataSource, UITableViewDelegate {
weak var secondaryDelegate: TableViewSecondaryDelegate?
let rowData: [String]
init(dataForRows: [String]) {
rowData = dataForRows
super.init()
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
return rowData.count
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
secondaryDelegate?.doSomething(indexPath.row)
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
....
return SomeCellForTheTableView
}
}
then make the secondary protocol:
protocol TableViewSecondaryDelegate {
func doSomething(row: Int)
}
then in your ViewController:
class myTableViewSceneController: UIViewController, TableViewSecondaryDelegate {
override func viewDidLoad() {
....
let tableViewDelAndDS = MyCustomTableViewDel(dataForRows: ["row0", "row1"])
tableViewDelAndDS.secondaryDelegate = self
tableView.delegate = tableViewDelAndDS
tableView.dataSource = tableViewDelAndDS
}
func doSomething(row: Int) { ... }
}