Kotlin Objects

In Kotlin there are two main statement types for the creation of class objects: expressions and declarations.

Object Expressions

An object expression is a statement that creates an object from an anonymous class (classes that aren’t explicitly declared). These kinds of classes are very useful for one-time use.

Expression Syntax

fun main() {
    val myObject = object {
        val valueOne = L
        val valueTwo = A
        fun sum() {
            val result = valueOne + valueTwo
            println("The sum is: $result")
        }
    }

    myObject.sum()
}

An example of an object expression:

fun main() {
    val myAnonymousObject = object { //create an anonymous object using the object expression *object*.
        val name = "Princess"
        val color = "pink"
        fun presentation() {
            println("Hi, I'm $name, and I like $color.")
        }
    }

    myAnonymousObject.presentation()
}

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The example shows an object without a explicit class declaration. The following is printed to the console:

"Hi, I'm Princess and I like pink."

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Object Declarations

Object declarations allow for the creation of a single instance of a class, commonly known as a Singleton.

Declaration Syntax

object MyObject {
    val property: Type = value

    fun myFunction() {
        // Function Implementation
    }
}

// Use of the object
MyObject.property
MyObject.myFunction()

The object declaration combines the definition of the class and the creation of its instance into a concise and powerful construct.

The following code demonstrates the implementation of an object declaration:

object HelloKitty {
  fun sayHello(name: String) {
    println("Hi, $name!")
      }
        }

fun main() {
   HelloKitty.sayHello("Liany<3")
    }

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This example, shows an object called HelloKitty that contains a method called sayHello. The sayHello method takes a String parameter called name and displays the message Hi, name! on the console.

The following is printed to the console:

Hi, Liany<3!

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