Kotlin DSL for Android's ColorStateList

colorStateList.kt

import android.content.res.ColorStateList
import android.util.StateSet
import androidx.annotation.AttrRes
import androidx.annotation.ColorInt

/**
 * **IMPORTANT**: Make sure to not use `android.R.attr.enabled` or friends,
 * but the `state_` prefixed attributes, like `android.R.attr.state_enabled`.
 *
 * Here are all the supported state attributes:
 * [android.R.attr.state_window_focused]
 * [android.R.attr.state_selected]
 * [android.R.attr.state_focused]
 * [android.R.attr.state_enabled]
 * [android.R.attr.state_pressed]
 * [android.R.attr.state_activated]
 * [android.R.attr.state_accelerated]
 * [android.R.attr.state_hovered]
 * [android.R.attr.state_drag_can_accept]
 * [android.R.attr.state_drag_hovered]
 * [android.R.attr.state_checked]
 *
 * Example usage:
 * ```kotlin
 * someView.backgroundTintList = colorStateList {
 *     addForState(android.R.attr.state_enabled, someColor)
 *     addForRemainingStates(disabledColor)
 * }
 * ```
 */
inline fun colorStateList(block: ColorStateListBuilder.() -> Unit): ColorStateList {
    return ColorStateListBuilder().apply(block).build()
}

class ColorStateListBuilder @PublishedApi internal constructor() {

    fun addForStates(
        @AttrRes vararg stateSet: Int,
        @ColorInt color: Int
    ) {
        entries.add(Entry(stateSet, color))
    }

    fun addForState(
        @AttrRes state: Int,
        @ColorInt color: Int
    ) {
        entries.add(Entry(intArrayOf(state), color))
    }

    fun addForRemainingStates(@ColorInt color: Int) {
        entries.add(Entry(StateSet.WILD_CARD, color))
    }

    @PublishedApi
    internal fun build(): ColorStateList {
        return ColorStateList(Array(entries.size) { i ->
            entries[i].stateSet
        }, IntArray(entries.size) { i ->
            entries[i].color
        })
    }

    private class Entry(
        @AttrRes val stateSet: IntArray,
        @ColorInt val color: Int
    )

    private val entries = mutableListOf<Entry>()
}

example.kts

someView.backgroundTintList = colorStateList {
    addForState(android.R.attr.state_enabled, someColor)
    addForRemainingStates(disabledColor)
}