How to call Kotlin function with function as parameter in Java Code?

Question

I have a kotlin method as follows:

fun methodWithCallBackAsParameter(callback:() -> Unit) {
    //Do Somejob
    callback()
}

In kotlin we simply use this method with following syntax:

methodWithCallBackAsParameter {
    //Some Instructions here.
}

Now I want to use this Kotlin method in a Java class but I am not able to figure out how.

Answer 1

只需在lambda表达式的末尾返回Unit.INSTANCE即可。

Answer 2

if you want to use lambda in android you have to change your app to use Java 1.8 instead of 1.7 use can do that by it from gradle

android {
  ...
  // Configure only for each module that uses Java 8
  // language features (either in its source code or
  // through dependencies).
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

for more look this documentation https://developer.android.com/studio/write/java8-support