Singleton with argument in Kotlin [duplicate]

Question

The Kotlin reference says that I can create a singleton using the object keyword like so:

object DataProviderManager {   fun registerDataProvider(provider: DataProvider) {     //   } } 

However, I would like to pass an argument to that object. For example an ApplicationContext in an Android project.

Is there a way to do this?

Answer 1

Since objects do not have constructors what I have done the following to inject the values on an initial setup. You can call the function whatever you want and it can be called at any time to modify the value (or reconstruct the singleton based on your needs).

object Singleton {     private var myData: String = ""      fun init(data: String)  {         myData = data     }      fun singletonDemo() {         System.out.println("Singleton Data: ${myData}")     } } 

Answer 2

Kotlin has a feature called Operator overloading, letting you pass arguments directly to an object.

object DataProviderManager {   fun registerDataProvider(provider: String) {       //   }    operator fun invoke(context: ApplicationContext): DataProviderManager {       //...       return this   } }  //... val myManager: DataProviderManager = DataProviderManager(someContext)