Mastering Kotlin

Defining an interface property

Kotlin allows us to define interface properties as well. An interface property can include a value assignment or can include just the property definition, in which case an implementing class is required to either provide a value or to be marked abstract. In the following example, we've added an id property to the GameObject interface:

interface GameObject {    val id: String    fun update(currentTime: Long)}

Our Player class is now required to either be marked abstract or to override the id property. In this case, id is overridden using a single expression:

class Player : GameObject {    override val id = "playerId"        override fun update(currentTime: Long) {        // add logic    }}

It's also possible to override an interface ...