CODEWITHSUNDEEP
kotlin
OMGPOP
OMGPOP

Reputation: 942

Kotlin "Any type that implements an interface"

I have a delegate interface: 

interface Delegate {
    fun didSelectWord(word: String)
}

And I would like to have a property called delegate

val delegate: <T> where T : Delegate

the delegate can be anything that implements Delegate

I have also tried 

val delegate: Any : Delegate

But both give compile error

Upvotes: 2

Views: 878

Answers (2)

Bob
Bob

Reputation: 13865

You can do like this:

class SomeClass<T : Delegate> {

     val delegate: T = // initialize delegate ...
}

Make the class a generic type that declares the type parameter T. And you can create properties of type T.

Upvotes: 0

creativecreatorormaybenot
creativecreatorormaybenot

Reputation: 126624

The solution is pretty easy

val delegate: Delegate

Now something like this works

interface Delegate

class Test: Delegate {
    fun yourMethod() = "Your Method" 
}

fun test() {
    val delegate: Delegate

    delegate = Test()

    println(delegate)
}

If you want to use a function that is only present in Test, but not in Delegate, you have to cast it

(delegate as Test).yourMethod()

Otherwise only functions that are present in Delegate will work

delegate.yourMethod() will not work.

Upvotes: 3

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