Mastering Kotlin

Specifying a use-site target

Let's look at how specifying different use-site targets impacts the generated Java code. We'll start by defining a simple ViewModel class:

class ViewModel( @param:ColorRes val resId:Int )

In this code snippet, we've added a @ColorRes annotation with a use-site of param. By adding this, the ColorRes annotation will be applied to the constructor parameter in the generated Java class:

public final class ViewModel {   private final int resId;   public final int getResId() {      return this.resId;   }   public ViewModel(@ColorRes int resId) {      this.resId = resId;   }}

The @ColorRes annotation is an annotation from the Android support library. It can be used to specify that an integer value represents a resource identifier.

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