toggle

Method used to add an element to a MutableCollection if it is not already contained or remove that element if already contained by the collection. The default behavior of the method is checking the existence in the collection of the element to toggle, but it can be used also to dynamically insert or remove an element from the collection from example with checkbox selection, button clicking, etc...

For example:

val mainCollection = mutableListOf(1, 2, 3)

// not contained element
val element = 4

mainCollection.toggle(
  element = element
)

println(mainCollection) // the result printed will be 1, 2, 3, 4

// contained element
val containedElement = 1

mainCollection.toggle(
  element = containedElement
)

println(mainCollection) // the result printed will be 2, 3, 4