Demo of simplistic preferences builder dsl

PreferenceDsl.kt

@Target(AnnotationTarget.TYPE)
@DslMarker
annotation class PreferenceDsl

@DslMarker
annotation class PreferenceBuilderDsl

@PreferenceBuilderDsl
interface BaseBuilder<out T> {
    fun build(): T
}

PreferenceScreen.kt

import androidx.annotation.StringRes

data class PreferenceScreen(
    @param:StringRes val titleRes: Int,
    val sections: List<PreferenceSection>,
) {
    class Builder: BaseBuilder<PreferenceScreen> {
        var titleRes: Int? = null
        var sections: MutableList<PreferenceSection> = mutableListOf()

        override fun build(): PreferenceScreen {
            return PreferenceScreen(
                titleRes = titleRes ?: error("title is required"),
                sections = sections.toList(),
            )
        }
    }
}

fun preferenceScreen(init: @PreferenceDsl PreferenceScreen.Builder.() -> Unit): PreferenceScreen {
    return PreferenceScreen.Builder().apply(init).build()
}

PreferenceSection.kt

import androidx.annotation.StringRes

sealed interface Preference

data class PreferenceSection(
    @param:StringRes val titleRes: Int,
    @param:StringRes val descriptionRes: Int?,
    val preferences: List<Preference>
) {
    class Builder : BaseBuilder<PreferenceSection> {
        var titleRes: Int? = null
        var descriptionRes: Int? = null
        val preferences = mutableListOf<Preference>()

        override fun build() = PreferenceSection(
            titleRes = titleRes ?: error("Title resource not set"),
            descriptionRes = descriptionRes ?: error("Description resource not set"),
            preferences = preferences.toList(),
        )
    }
}

fun PreferenceScreen.Builder.preferenceSection(block: @PreferenceDsl PreferenceSection.Builder.() -> Unit) {
    sections.add(PreferenceSection.Builder().apply(block).build())
}

rootPreferenceScreen.kt

val rootPreferenceScreen = preferenceScreen {
    titleRes = 12345

    preferenceSection {
        titleRes = 12345

        switchPreference {
            titleRes = 12345
            key = "12345"
        }

        switchPreference {
            titleRes = 12345
            key = "12345"
        }

        switchPreference {
            titleRes = 12345
            key = "12345"
        }
    }

    someSubSection()
}

someSubSection.kt

fun PreferenceScreen.Builder.someSubSection() = preferenceSection {
    titleRes = 12345

    switchPreference {
        titleRes = 12345
        key = "12345"
    }

    switchPreference {
        titleRes = 12345
        key = "12345"
    }

    switchPreference {
        titleRes = 12345
        key = "12345"
    }
}

SwitchPreference.kt

import androidx.annotation.StringRes

data class SwitchPreference(
    @param:StringRes val titleRes: Int,
    @param:StringRes val summaryRes: Int?,
    val key: String,
    val enabled: Boolean = true,
) : Preference {
    internal class Builder : BaseBuilder<SwitchPreference> {
        var titleRes: Int? = null
        var summaryRes: Int? = null
        var key: String = ""
        var enabled: Boolean = true

        override fun build(): SwitchPreference {
            require(key.isNotBlank()) { "key must be set" }

            return SwitchPreference(
                titleRes = titleRes ?: error("title must be set"),
                summaryRes = summaryRes,
                key = key,
                enabled = enabled,
            )
        }
    }
}

internal fun PreferenceSection.Builder.switchPreference(init: @PreferenceDsl SwitchPreference.Builder.() -> Unit) {
    preferences.add(SwitchPreference.Builder().apply(init).build())
}