我试图用以下函数扩展String类型的枚举类，但无法在调用站点使用它:
fun <T: Enum<String>> Class<T>.join(skipFirst: Int = 0, skipLast: Int = 0): String {
return this.enumConstants
.drop(skipFirst)
.dropLast(skipLast)
.map { e -> e.name }
.joinToString()
}
MyStringEnum.join(1, 1);
What am I doing wrong here?
我建议采取以下解决方案:
fun <T : Enum<*>> KClass<T>.join(skipFirst: Int = 0, skipLast: Int = 0): String {
return this.java
.enumConstants
.drop(skipFirst)
.dropLast(skipLast)
.map { e -> e.name }
.joinToString()
}
Instead of attaching extension function to Class, i attached it to KotlinClass.
现在，您可以简单地使用它:
enum class Test {ONE, TWO, THREE }
fun main(args: Array<String>) {
println(Test::class.join())
}
// ONE, TWO, THREE