Enum.valueOf in Kotlin
Crash-safe Solution
Create an extension and then call valueOf<MyEnum>("value")
. If the type is invalid, you'll get null and have to handle it
inline fun <reified T : Enum<T>> valueOf(type: String): T? {
return try {
java.lang.Enum.valueOf(T::class.java, type)
} catch (e: IllegalArgumentException) {
null
}
}
Alternatively, you can set a default value, calling valueOf<MyEnum>("value", MyEnum.FALLBACK)
, and avoiding a null response. You can extend your specific enum to have the default be automatic
inline fun <reified T : Enum<T>> valueOf(type: String, default: T): T {
return try {
java.lang.Enum.valueOf(T::class.java, type)
} catch (e: IllegalArgumentException) {
default
}
}
Or if you want both, make the second:
inline fun <reified T : Enum<T>> valueOf(type: String, default: T): T = valueOf<T>(type) ?: default
Your function works if you specify the type parameter value explicitly:
val value = safeValueOf<TestEnum>("test")
The original code is supposed to work as well, but doesn't work because of a bug in the type inference implementation: https://youtrack.jetbrains.com/issue/KT-11218
I would typically add something like this to enum:
companion object {
fun from(type: String?): TestEnum = values().find { it.name == type } ?: DEFAULT
}
this would make a clean call
val value = TestEnum.from("test")
of course you can make it return null