Member Properties in Kotlin

In Kotlin, member properties are the variables that are defined inside a class. These properties can be initialized in the constructor or during declaration. Member properties can be defined as var or val, which stands for mutable and immutable properties respectively.

Declaring Member Properties

To declare a member property in Kotlin, you need to follow the following syntax:

class MyClass {
    var mutableProperty: Int = 0 //Mutable Property
    val immutableProperty: String = "Hello World" //Immutable Property
}

In the above example, mutableProperty is declared as a mutable property of MyClass, which can be changed later on. The immutableProperty, on the other hand, is defined as an immutable property and cannot be changed once it is initialized.

Accessing Member Properties

To access member properties of a Kotlin class, you can use the . operator to access the properties of an object of that class. For example,

val obj = MyClass()
println(obj.mutableProperty) // Output: 0
println(obj.immutableProperty) // Output: Hello World

In the above example, we have created an object of MyClass and accessed its mutableProperty and immutableProperty using the . operator.

Setter and Getter Methods

In Kotlin, setter and getter methods for member properties of a class are automatically generated by default. For mutable properties, a setter method is generated that allows changing the value of the property. For immutable properties, only a getter method is generated.

class MyClass {
    var mutableProperty: Int = 0 //Mutable Property
        set(value) {
            field = value
        }
    val immutableProperty: String = "Hello World" //Immutable Property
        get() {
            return field
        }
}

In the above example, we have defined a custom setter method for the mutableProperty, where the value is set to the field of the property. The get() method for the immutableProperty simply returns the value of the field.

Conclusion

Member properties in Kotlin provide an easier way to define and access properties of a class. They can be defined as var or val and can be accessed using the . operator. Setter and getter methods are automatically generated by Kotlin, but can also be defined manually if required.