constructor with class parameter in Kotlin

Question

I want to have Kotlin class with constructor and get another class as parameter like this.

class LogHelper(cls : class) {

}

I had the same class in java and I didn't have any problem with it.

public LogHelper(Class cls) {
    LOG_TAG = cls.getSimpleName();
}

`class` is a [keyword](https://kotlinlang.org/docs/reference/keyword-reference.html), [`Class`](https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html) is a Java class. [Class names typically start with a capital letter even in Kotlin.](https://kotlinlang.org/docs/reference/coding-conventions.html#naming-rules) — Eugen Pechanec, Mar 10 '19 at 12:09

BigSt · Accepted Answer · 2019-03-10T12:31:41.870

3

You can use constructor with java.lang.Class parameter:

class LogHelper(cls: Class<*>) {
    val LOG_TAG = cls.simpleName
}

or Kotlin's KClass:

class LogHelper(cls: KClass<*>) { ... }

* - Star Projection, used to indicate we have no information about a generic argument.

Kotlin does not allow raw generic types (e.g. Class), you always have to specify the type parameter (e.g. Class<*>, Class<Any>, Class<SomeClass>).

edited Mar 10 '19 at 12:31

answered Mar 10 '19 at 12:04

BigSt

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Thanks for your answer. the right answer for my question was KClass and I find out because of your suggestion. Please add it in your answer. – Ali shatergholi Mar 10 '19 at 12:17
@Alishatergholi it may be worth mentioning that raw types are heavily discouraged even in Java. – Salem Mar 10 '19 at 12:27
@Moira do you have any link to explain when we should use raw type. – Ali shatergholi Mar 10 '19 at 12:35
1

@Alishatergholi if possible, [never](https://stackoverflow.com/questions/2770321/what-is-a-raw-type-and-why-shouldnt-we-use-it). They are not type safe. – Salem Mar 10 '19 at 12:51

constructor with class parameter in Kotlin

1 Answers1