steliosfran

class ChatViewModel(
    loadChatMessagesUseCase: LoadChatMessagesUseCase,
    private val getChatMessagesUseCase: GetChatMessagesUseCase,
    private val sendTextMessageUseCase: SendTextMessageUseCase,
    private val user: User
) : BaseViewModel() {

    data class State(
        val messages: List<MessageUiModel>
    )

steliosfran

fun createMoshi(): Moshi {
    return Moshi.Builder()
        .add(createEnumJsonAdapter<Role>())
        .add(createEnumJsonAdapter<Category>())
        .add(createEnumJsonAdapter<AnotherEnum>())
        // ...
        .build()
}

steliosfran

inline fun <reified T> createEnumJsonAdapter(): JsonAdapter<T> where T : Enum<T>, T : IEnumValue {
    return object : JsonAdapter<T>() {
        @FromJson
        override fun fromJson(reader: JsonReader): T? {
            return if (reader.peek() != JsonReader.Token.NULL) {
                enumValues<T>().firstOrNull { it.value == reader.nextInt() }
            } else {
                reader.nextNull()
            }
        }

steliosfran

class GenericEnumJsonAdapter<T> : JsonAdapter<T>() {
    @FromJson
    override fun fromJson(reader: JsonReader): T? {
        // Cannot access enumValues<T>()
    }

    @ToJson
    override fun toJson(writer: JsonWriter, value: T?) {
        // ...
    }

steliosfran

enum class Role(override val value: Int) : IEnumValue {
    Admin(1),
    Moderator(2)
}

object GenericEnumFactory {
    inline fun <reified T> fromValueOrNull(rawValue: Int?): T? where T : Enum<T>, T : IEnumValue {
        return enumValues<T>().firstOrNull { it.value == rawValue }
    }
}

steliosfran

interface IEnumValue {
    val value: Int
}

enum class Role(override val value: Int) : IEnumValue {
    Admin(1),
    Moderator(2);

    companion object {
        fun fromValueOrNull(value: Int): Role? {

steliosfran

class RoleEnumJsonAdapter : JsonAdapter<Role>() {
    @FromJson
    override fun fromJson(reader: JsonReader): Role? {
        return if (reader.peek() != JsonReader.Token.NULL) {
            Role.fromValueOrNull(reader.nextInt())
        } else {
            reader.nextNull()
        }
    }

steliosfran

enum class Role(val value: Int) {
    Admin(1),
    Moderator(2);

    companion object {
        fun fromValueOrNull(value: Int): Role? {
            return values().firstOrNull { it.value == value }
        }
    }
}

steliosfran

{
    "name": "John",
    "role": 1
}

steliosfran

{
    "name": "John",
    "role": "Admin"
}