How to create an Enum class that takes multiple parameters but only uses one of them for comparison initialization? - kotlin

Question

I want my enum class to take two parameters but only use one of them when comparing which type to initialize. Here I want the id to be passed during initialization as well but not use it to control which type gets created.
enum class ActionEnum(val action: String, val id: String) {
URL("URL") {
override fun start() {
openUrl(id)
}
},
START_FRAGMENT("FRAG") {
override fun start() {
startFragmentWithId(id)
}
},
START_POPUP("POPUP"){
override fun start() {
startPopUpWithMessage(id)
}
};
open fun start() {
}
}

Answer 1

From your question is not really clear what you intend to do with the parameter action, but I think that what you are looking for are sealed classes.
Instead of defining an enum, you can define a sealed class like this
sealed class ActionEnum(val action: String, val id: String) {
class URL(action: String): ActionEnum(action, "URL") {
override fun start() {
openUrl(id)
}
}
class START_FRAGMENT(action: String): ActionEnum(action, "FRAG") {
override fun start() {
startFragmentWithId(id)
}
}
class START_POPUP(action: String): ActionEnum(action, "POPUP") {
override fun start() {
startPopUpWithMessage(id)
}
};
open fun start() {
}
}
You can use that like an enum which means that e.g. you have exhaustive when without the need for an else clause:
val a: ActionEnum = ActionEnum.URL("some action")
when(a) {
is ActionEnum.URL -> ...
is ActionEnum.START_FRAGMENT -> ...
is ActionEnum.START_POPUP -> ...
// no more cases possible because ActionEnum is sealed
}
But you can have different instances of each "enum" element where action can have a different value - which is not possible with real enums.