CODEWITHSUNDEEP
arraysswiftclasstableview
Ross Morey
Ross Morey

Reputation: 33

Creating an array of all objects of a class

Is there a way of creating an array of all colour objects created? So that every time a new colour is added, it is also automatically added to the array?

class Colours {
    var colourName: String
    var colourShades: [String?]


    init(colourName: String, colourShades: [String?]) {
        self.colourName = colourName
        self.colourShades = colourShades
    }


}

var red = Colours(colourName: "Red", colourShades: ["Crimson", "Cherry", "Rose"])


var blue = Colours(colourName: "blue", colourShades:["Ice", "Baby", "Royal"])

To give some context I am attempting to develop an app for IOS which includes a table of colours. Then when a user clicks on a colour it will take them to another table which has shades of that colour.

I want the array of colours so that I can automatically fill in the rows of the table, and then when a user adds a new colour it will automatically add a new row.

Upvotes: 3

Views: 98

Answers (4)

Adrian Bobrowski
Adrian Bobrowski

Reputation: 2794

1) Add your own notification name

extension NSNotification.Name {

    // 1
    static let NewColourAdded = NSNotification.Name(rawValue: "NewColourAdded")
}

2) Set access modifier for the object pool (static variable all) as private(set)

3) Add an initialized colours to the object pool

4) Post your notification

class Colours {

    // 2
    private(set) static var all: [Colours] = []

    var name: String
    var shades: [String]

    init(name: String, shades: [String]) {
        self.name = name
        self.shades = shades

        // 3
        Colours.all.append(self)

        // 4
        NotificationCenter.default.post(
            name: .NewColourAdded, 
            object: self
        )
    }
}

usage

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        NotificationCenter.default.addObserver(
            self, 
            selector: #selector(self.onNewColourAdded), 
            name: .NewColourAdded, 
            object: nil
        )
    }

    func onNewColourAdded(notification: Notification) {
        guard let newColours = notification.object as? Colours else { 
            return 
        }

        // Do something
    }
}

Upvotes: 1

vacawama
vacawama

Reputation: 154593

Use a static array defined in Colours to hold all colours that have been created. You can access this array as Colours.allColours from anywhere in your app.

Create a protocol called ColourWatcher and create a static delegate on Colours for a class that will be notified when a colour is added.

Have your tableView implement ColourWatcher and add itself as the delegate. Then, when a colour is added, the method newColourAdded will be called in your TableViewController and you can reload the data.

Also, I would recommend making the array of colour shades just be [String] instead of using optionals. An empty array will signify that you have no shades.

protocol ColourWatcher: class {
    func newColourAdded(colour: Colour)
}

class Colours {
    static var allColours: [Colours] = []
    static weak var delegate: ColourWatcher?

    var colourName: String
    var colourShades: [String]

    init(colourName: String, colourShades: [String]) {
        self.colourName = colourName
        self.colourShades = colourShades
        Colours.allColours.append(self)
        Colours.delegate?.newColourAdded(colour: self)
    }
}

class MyTableViewController: UIViewController, ColourWatcher {

    func viewDidLoad() {
        super.viewDidLoad()
        Colours.delegate = self
    }

    func newColourAdded(colour: Colour) {
        // reload table view or just insert a new row
        // using the passed in colour
    }
}

Upvotes: 3

ndPPPhz
ndPPPhz

Reputation: 325

In my opinion, you want to preserve a state in the whole application.

The best way for solving your problem is creating a Singleton instance.

E.g. 

class ColoursSharedModel {

    static let shared : ColoursSharedModel = ColoursSharedModel()

    var choosenColors : [Colors] = []
    private init() {}
}

Later, you should add 

ColoursSharedModel.shared.choosenColors.append(self)

in your Colors' init.

Upvotes: 1

Hussain Shabbir
Hussain Shabbir

Reputation: 15015

Is there a way of creating an array of all colour objects created? So that every time a new colour is added, it is also automatically added to the array?

You can declare one array in your class and append like this

lazy var colorList = {
  Colours()
}()

I want the array of colours so that I can automatically fill in the rows of the table, and then when a user adds a new colour it will automatically add a new row.

func addColor() {
   colorList.append(Colours(colourName: "Red", colourShades: 
   ["Crimson", "Cherry", "Rose"]))
   colorList.append(Colours(colourName: "blue", colourShades:["Ice", 
   "Baby", "Royal"]))
}

once you invoke the above method when add the color then refresh the table to appear the new color information on your table row.

To give some context I am attempting to develop an app for IOS which includes a table of colours. Then when a user clicks on a colour it will take them to another table which has shades of that colour.

Now in your tableView cellForrowatindexpath method you just need to access the above colorlist array and fetch the colorname and display on your table.

And when user tap on the cell then inside your didSelecteRowAtIndexpath method load the another class and pass the above colorList array information to that class and in order to display the shade of color access the colourShades information from the colorList array.

Upvotes: 1

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