How do I call Kotlin functions with lambdas in the parameter from a Java class.
Example
fun getToken(
tokenUrl: String,
onSuccess: (String) -> Unit,
onError: (Error) -> Unit
): Provider {
//Implementation
}
-
A lambda is just a closure in KotlinAbhijit Sarkar– Abhijit Sarkar2019-05-29 21:05:47 +00:00Commented May 29, 2019 at 21:05
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3 Answers
You can do this
value.getToken("url",
new Function1<String, Unit>() {
@Override
public Unit invoke(String s) {
/* TODO */
return Unit.INSTANCE;
}
}, new Function1<Throwable, Unit>() {
@Override
public Unit invoke(Throwable throwable) {
/* TODO */
return Unit.INSTANCE;
}
});
3 Comments
murthy10
Don't forget to add
return Unit.INSTANCE; in the invoke method.
Haroon
This comment should be part if the answer. @Francesc can you please update your answer to include the comment? Thanks
k314159
While this answer is correct, I would much prefer Louis's answer.
You can call it with normal Java 8 lambdas, since Kotlin is actually using a single-method interface on the backend.
myFoo.getToken(tokenUrl, successString -> { ... }, error -> { ... });
1 Comment
Alan
Thanks! Unfortunately my project is not set to Java 8.
This is for calling it within Kotlin, the question was edited to say "from Java" after I provided my answer. Leaving it here anyway in hope that it is useful.
You can call it like this
fun test() {
getToken("asdf", { print(it) }, { println(it) })
getToken("asdf", { print(it) }) { err -> println(err) }
getToken("asdf", ::println, ::println)
getToken("asdf", ::println) { println(it) }
}
4 Comments
Alan
I know how to call it within Kotlin. I want to call the function from a Java class.
RedDeckWins
Your original question was edited. Before it didn't say from Java. I think the downvotes I received were unnecessary.
Alan
it did, but it was only in the title. I added it in the body after you answered it incorrectly for additional clarification.
Call Kotlin function with Lambda parameters in Java. I think your downvote of my question is unnecessary.RedDeckWins
I didn't downvote your question. Also I assumed other people downvoted my answer since you had the full context and would understand why my answer was seemingly incorrect.