How to create an instance of anonymous interface in Kotlin?
Assuming the interface has only a single method you can make use of SAM.
val handler = Handler<String> { println("Hello: $it") }
Since version 1.4 Kotlin supports SAM for interfaces defined in Kotlin. That requires prefixing the interface
keyword with fun
fun interface Handler<C> {
fun call(context: C);
}
If you have a method that accepts a handler then you can even omit type arguments:
fun acceptHandler(handler:Handler<String>){}
acceptHandler(Handler { println("Hello: $it") })
acceptHandler({ println("Hello: $it") })
acceptHandler { println("Hello: $it") }
If the interface has more than one method the syntax is a bit more verbose:
val handler = object: Handler2<String> {
override fun call(context: String?) { println("Call: $context") }
override fun run(context: String?) { println("Run: $context") }
}
I had a case where I did not want to create a var for it but do it inline. The way I achieved it is
funA(object: InterfaceListener {
override fun OnMethod1() {}
override fun OnMethod2() {}
})