Kotlin: Override setter

Question

I have an abstract class containing the following property

var items: List<I> = listOf()
    set(value) {
        field = value
        onDataChanged()
    }

In my extending class i now want to override the setter of items to do additional stuff before the above setter code is called. Is this possible, if yes, how?

Answer 1

You have to declare your field as open in your parent class

open var items: List<I> = listOf()
    set(value) {
        field = value
        onDataChanged()
    }

And in your child class you override it as:

override var items: List<Int>
    get() = super.items
    set(value) {
        super.items = value
        //Your code
    }

In this way, you are actually creating a property without a backing field and you are just accessing to the real parent's items field.

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