Kotlin Essential Training

Chapter 7 - Section 3

	fun main(args: Array<String>) {
		val stateful = StatefulClass(object : ClickListener {
			override fun onClick(event: ClickEvent) {
				println("Click at ${event.x}, ${event.y}")
			}
		})
		println("Listener initialized")
		stateful.clickMe(5, 18)
		stateful.clickMe(45, 57)

	}

	class ClickEvent(val x: Int, val y: Int)

	interface ClickListener {
		fun onClick(event: ClickEvent)
	}

	class StatefulClass(listener: ClickListener) {
		private var _clickListener:ClickListener? = listener

		fun clickMe(x: Int, y: Int) {
			_clickListener?.onClick(ClickEvent(x, y))
		}
	}