How can I change the Voiceover value of a UIButton programmatically?

Question

I've created a UISwitch in InterfaceBuilder to toggle audio on and off. The switch works fine, but I want to change the value that Voiceover reads out from the current '0' and '1' to 'Off' and 'On'. My code is as follows:

import UIKit

class AudioStreamTableViewCell: UITableViewCell {
    weak var controller: EventDetailsViewController!
    weak var audioInterface: EventAudioInterface? { didSet { if self.audioInterface !== oldValue { self.updateUI() }}}
    func updateUI() {}
    override func awakeFromNib() {
        super.awakeFromNib()
        self.updateUI()
    }

}

class MuteStreamTableViewCell: AudioStreamTableViewCell {
    static let identifier = "MuteStreamTableViewCell"

    @IBOutlet var muteSwitch: UISwitch!

    override func updateUI() {
        self.muteSwitch.isOn = self.audioInterface?.muted ?? false
    }

    @IBAction func switchChanged(_ muteSwitch: UISwitch) {
        self.controller.setMuted(muteSwitch.isOn, on: self.audioInterface)

        if muteSwitch.isOn {
            self.muteSwitch.accessibilityValue = "on"
        } else {
            self.muteSwitch.accessibilityValue = "off"
        }
    }

}

Voiceover still speaks '0' and '1'. What am I doing wrong?

Thanks!!

Answer 1

Swift 4.2

I had to subclass UISwitch and override accessibilityValue .

class AccessibilityUiSwitch: UISwitch {
    override var accessibilityValue: String? {
        get {
            return isOn ? "on" : "off"
        }
        set {
            self.accessibilityValue = newValue
        }
    }
}