Android - Kotlin

Kotlin-Demo.kt

interface Demo {
    val context:Context
    fun alert(mensaje:String)
    {
        Toast.makeText(context, message, Toast.LENGTH_SHORT).show()
    }
}

object SimpleSingleton {
    val answer = 42;
    fun greet(name: String) = "Hello, $name!"
}

//val is like a constant
data class Item (val name: String, var year: Int?) {
    
}

val item = Item(name = "Moto", year = 2014)
val item2 = item.copy(year = null)

// Funciones extendidas
fun Activity.alert(mensaje:String)
{
    Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
}