The isNullOrEmpty method returns True if the MutableList is either null or empty.
fun <T> Collection<T>?.isNullOrEmpty(): Boolean
This method doesn’t take any argument.
This method returns a Boolean value. Returns True if the MutableList is null or empty. Otherwise, False is returned.
The below code demonstrates how to use the isNullOrEmpty method:
fun main() {// create a null listval nullList: MutableList<Any>? = nullprintln("nullList is =>$nullList")println("nullList.isNullOrEmpty() => ${nullList.isNullOrEmpty()}") // true// create an empty listval emptyList= mutableListOf<Int>()println("\nemptyList is =>$emptyList")println("emptyList.isNullOrEmpty() => ${emptyList.isNullOrEmpty()}") // true// create an non-empty and not-null listval validList = mutableListOf(1)println("\nvalidList is =>$validList")println("validList.isNullOrEmpty() => ${validList.isNullOrEmpty()}") // false}
Line 3: We create a variable nullList with type as MultableList and assign null as value.
Line 5: We call the isNullOrEmpty method of the nullList. The value of the nullList variable is null so True is returned.
Line 8: We create an empty MultableList (variable name nullList) by calling the multableListOf method without argument.
Line 10: We call the isNullOrEmpty method of the emptyList. The emptyList contains no elements so True is returned.
Line 13: We create a MultableList(variable name validList) by calling the multableListOf method with the 1 and 2 argument. The multableListOf method returns an MultableList object with [1,2] as elements.
Line 15: We call the isNullOrEmpty method of the validList. The validList contains two elements so False is returned.