Hey everyone, is there any way to specify the valu...

# multiplatform

[Tiago Nunes]

Hey everyone, is there any way to specify the values for common fields of an enum class in commonMain?

This is what I know works:

commonMain:

expect enum class ImageTargetType {
    USER,
    DEVICE;

    val code: String
}

androidMain:

actual enum class ImageTargetType(
    actual val code: String,
    @DrawableRes val defaultImageResId: Int?,
) {
    USER("User", R.drawable.ic_default_user),
    DEVICE("Device", null),
}

This is what I wanted:

commonMain:

expect enum class ImageTargetType(val code: String) {
    USER("User"),
    DEVICE("Device);
}

androidMain:

actual enum class ImageTargetType(
    @DrawableRes val defaultImageResId: Int?,
) {
    USER(R.drawable.ic_default_user),
    DEVICE(null),
}

[russhwolf]

I don't think it's possible the way you're trying, but maybe you can use two different types instead

// common
enum class CommonImageTargetType(val code: String) {
    USER("User"),
    DEVICE("Device);
}

// android
enum class AndroidImageTargetType(
    val commonImageTargetType: CommonImageTargetType,
    @DrawableRes val defaultImageResId: Int?,
) {
    USER(CommonImageTargetType.USER, R.drawable.ic_default_user),
    DEVICE(CommonImageTargetType.DEVICE, , null),
}

[Tiago Nunes]

Thanks @russhwolf that's a great idea! But then the compiler doesn't force me to specify all entries of the enum

[russhwolf]

Yeah, there's always tradeoffs

[russhwolf]

If you add functions to convert between them then you can recover that compile-safety with when checks

[russhwolf]

fun CommonImageTargetType.toAndroidImageTargetType() = when { ... }

[russhwolf]

you're still vulnerable to copy-paste errors if you associate the wrong values together, but that's a lower risk probably

[Tiago Nunes]

Hm that's also a good idea, if there are lots of common fields it might be the best solution