Theme Change

ThemeManager.kt

class CustomTextView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : AppCompatTextView(context, attrs, defStyleAttr), ThemeChangeListener {

    override fun onAttachedToWindow() {
        super.onAttachedToWindow()
        AdmiralUI.addListener(this)
    }

    override fun onDetachedFromWindow() {
        AdmiralUI.removeListener(this)
        super.onDetachedFromWindow()
    }
    
    override fun onThemeChanged(theme: Theme) {
        // todo change theme
    }
}

object ThemeManager {

    private val listeners = mutableSetOf<ThemeChangeListener>()

    var theme: Theme = Theme.fromPalette()
        set(value) {
            field = value
            listeners.forEach { listener -> listener.onThemeChanged(value) }
        }

    internal fun addListener(listener: ThemeChangeListener) = listeners.add(listener)

    internal fun removeListener(listener: ThemeChangeListener) = listeners.remove(listener)
}

internal interface ThemeChangeListener {
    fun onThemeChanged(theme: Theme)
}

data class Theme(
    val primary: String = "#ffffff",
    val primaryOn: String = "#000000"
)