How do I change the text color of UIPickerView with multiple components in Swift?

Question

Below code will change the font colour of the picker view of all 3 components. However, it crash when I try to spin the wheel. I think it has to do with the didSelectRow function. Maybe the two function have to be nested somehow? Any idea?

    func pickerView(pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    var attributedString: NSAttributedString!
    if component == 0 {
        attributedString = NSAttributedString(string: a.text!, attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    }
    if component == 1 {
        attributedString = NSAttributedString(string: b.text!, attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    }
    if component == 2 {
        attributedString = NSAttributedString(string: c.text!, attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    }
    return attributedString
}


func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int){

    switch component {
    case 0:
        aOutput.text = a[row]      -->  **Code breaks**
    case 1:
        bOutput.text = b[row]
    case 2:
        cOutput.text = c[row]
    default:
        10
    }

Slander

Have you tried anything? You should try and make some effort before asking. – Faithfaithful

Yes of course, spent hours and hours, enrolled in 2 courses - been working on this app for a week non-stop from scratch with no programming background. But it is hard, all the tutorials are in playground. SO while I get the logic right, I have trouble understanding what code goes where. All the initialising (I think it is called) and scope of swift/object C. – Slander

and the Scope. It doesn't help to know how to write a switch/case statement in Playground if you don't understand what statement like "var mySpeechSynthesizer: AVSpeechsynthesizer..." is, where it goes and the order of how you call them and what to call them. I don't even know the name of what I don't know...lol How do you figure out stuff like that without asking, tell me because I can't find it in the e-book or in course or on Youtube – Slander

Answer 1

The following pickerView:attributedTitleForRow:forComponent: method implementation should help you:

func pickerView(pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    let attributedString = NSAttributedString(string: "some string", attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    return attributedString
}

Update

If you want to use attributedString in multiple if or switch statements, the following UIViewController subClass example will help you:

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

    @IBOutlet weak var picker: UIPickerView!

    let arrayOne = ["One", "Two", "Three", "Four", "Five", "Six"]
    let arrayTwo = ["Un", "Deux", "Trois", "Quatre", "Cinq", "Six"]
    let arrayThree = [1, 2, 3, 4, 5, 6]


    override func viewDidLoad() {
        super.viewDidLoad()

        picker.delegate = self
        picker.dataSource = self
    }

    func numberOfComponentsInPickerView(_: UIPickerView) -> Int {
        return 3
    }

    func pickerView(_: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        switch component {
        case 0:
            return arrayOne.count
        case 1:
            return arrayTwo.count
        case 2:
            return arrayThree.count
        default:
            return NSNotFound
        }
    }

    func pickerView(pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
        var attributedString: NSAttributedString!

        switch component {
        case 0:
            attributedString = NSAttributedString(string: arrayOne[row], attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
        case 1:
            attributedString = NSAttributedString(string: arrayTwo[row], attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
        case 2:
            attributedString = NSAttributedString(string: toString(arrayThree[row]), attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
        default:
            attributedString = nil
        }

        return attributedString
    }

    func pickerView(_: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        switch component {
        case 0:
            println(arrayOne[row])
        case 1:
            println(arrayTwo[row])
        case 2:
            println(arrayThree[row])
        default:
            break
        }
    }

}

Misfortune

Hi, thank you so much, that changed the color! However it also changed the array - the text in the picker view. I guess I am meant to replace it with the name of the array? There is another complicating factor, i have 3 components (i.e. 3 columns. – Slander

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int{ return 3 } func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{ switch component { case 0: return a.count case 1: return b.count case 2: return c.count default: return 10 } } – Slander

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String!{ switch component { case 0: return a[row] case 1: return b[row] case 2: return c[row] default: return "oops" } } – Slander

Thank you for your response ! Line: let attributedString: NSAttributedString! --> error/yellow: Immutable value is default initialised and can never be changed. Line(s) attributedString = NSAttributedstring.... --> error/red: Cannot assign to 'let' value 'attributedString' – Slander

Wow, that almost worked! Now the picker view has changed color and the components are "initialised with the first value in the array. However, when I flick the wheel it stays at the first value in the array. Xcode also shows a green breakpoint on the first iteration of the func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int){. I think your code must somehow be "nested" inside the other code or visa versa so that the wheel are filled with all the value in a.text, b.text and c.text. I will update question. – Slander

I've edited my answer with a UIViewController subClass containing a UIPickerView (IBOutlet) with 3 components and text in red. It worked fine with a Xcode Single View Application template. – Misfortune

I had some real issues in other parts of the code with casting variables between string and Int. And I noticed something in your code which I rewrote to --> NSString(string: toString(arrayOne[0])) and --> return NSString(string: toString(arrayOne[row])). Both solved to other issues I had. But while I have a gut feeling about what they do, and it is why I tried it, I am not quite sure what it does, it just solved a lot of errors. Can you explain please? – Slander

Yes of course, but I can't, yet, I need 15 in reputation before I can vote... I will though ! Thanks – Slander

Answer 2

Swift 4.0

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    return NSAttributedString(string: pickerData[row], attributes: [NSAttributedStringKey.foregroundColor : UIColor.white])
}

Pumpernickel

Answer 3

Swift 3

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
        let attributedString = NSAttributedString(string: "YOUR STRING", attributes: [NSForegroundColorAttributeName : UIColor.white])
        return attributedString
    }

Vehicle

Answer 4

Swift 5

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    return NSAttributedString(string: pickerData[row], attributes: [NSAttributedString.Key.foregroundColor : UIColor.white])
}

Polacre

Answer 5

enter image description hereThis code snippet works for me

extension UIPickerView {
@IBInspectable var pickerTextColor:UIColor? {
    get {
        return self.pickerTextColor
    }
    set {
        self.setValue(newValue, forKeyPath: "textColor")
    }
}}

Slavic