how to modify an array from another class

Question

Im making to do list-app which consist of 2 View Controllers one with table view hold an array and display it and second one with a textField, a button function to append the text field's text to the array to display the new appended string it in the first view controller heres my code:

class ViewController: UIViewController,UITableViewDataSource,UITableViewDelegate {

@IBOutlet weak var tableView: UITableView!

var exmpArray = ["DDDD","rrr","TTT"]

override func viewDidLoad() {
    super.viewDidLoad()

    tableView.delegate = self
    tableView.dataSource = self
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}
@IBAction func addBtnBar(_ sender: Any) {
    performSegue(withIdentifier: "showMe", sender: nil)
}

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

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

    let cell = tableView.dequeueReusableCell(withIdentifier: "cell")
    cell?.textLabel?.text = exmpArray[indexPath.row]  
    return cell!
}}

and the second one is:

class SecondViewController: UIViewController {

@IBOutlet weak var myTextField: UITextField!

var realAry:[String] = []

override func viewDidLoad() {
    super.viewDidLoad()

}

let myObj = ViewController()

@IBAction func addBtn(_ sender: Any) {

    myObj.exmpArray.append(myTextField.text!)
    print(myObj.exmpArray)        

}

after appending the new words it doesn't display in the first controller

Duncan C · Accepted Answer · 2017-07-15 15:33:58Z

2

One problem is this line:

let myObj = ViewController()

That creates a new instance of ViewController that has nothing to do with the view controller that called you. Get rid of that line. It's wrong.

You need to set up a delegate property in SecondViewController that points back to ViewController, define a protocol for that delegate to conform to, and use that protocol so that SecondViewController can notify it's delegate when the array changes.

In ViewController, add a prepareForSegue() function that takes the destination view controller, casts it to type SecondViewController, and sets SecondViewController's delegate to self.

answered Jul 15, 2017 at 15:33

Duncan C

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Comments

Bilal · Accepted Answer · 2017-07-15 16:24:56Z

1

Both arrays are different you are just copying first VC array to 2nd VC array. Array is value type in swift. Instead of creating 2 arrays make 1st VC array as static.

static var exmpArray = ["DDDD","rrr","TTT"]

Now you can use & update this in all VC by calling like below

FirstVC.exmpArray

edited Jul 15, 2017 at 16:24

Bilal

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answered Jul 15, 2017 at 15:12

Dharma

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2 Comments

OT AMD Over a year ago

thanks that worked --- i can see the new values when i print it in the console but now i only need to use tableView.reloadData() to show it in the table ... can you please advice where i can implement this function in my class ?

Duncan C Over a year ago

Who downvoted this? Its a reasonable answer, and provides useful information.

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