Kotlin 1.5.0 Help

This expressions

To denote the current receiver, you use this expressions:

If this has no qualifiers, it refers to the innermost enclosing scope. To refer to this in other scopes, label qualifiers are used:

Qualified this

To access this from an outer scope (a class, extension function, or labeled function literal with receiver) you write this@label, where @label is a label on the scope this is meant to be from:

class A { // implicit label @A inner class B { // implicit label @B fun Int.foo() { // implicit label @foo val a = this@A // A's this val b = this@B // B's this val c = this // foo()'s receiver, an Int val c1 = this@foo // foo()'s receiver, an Int val funLit = lambda@ fun String.() { val d = this // funLit's receiver } val funLit2 = { s: String -> // foo()'s receiver, since enclosing lambda expression // doesn't have any receiver val d1 = this } } } }

Implicit this

When you call a member function on this, you can skip the this. part. If you have a non-member function with the same name, use this with caution because in some cases it can be called instead:

fun main() { //sampleStart fun printLine() { println("Top-level function") } class A { fun printLine() { println("Member function") } fun invokePrintLine(omitThis: Boolean = false) { if (omitThis) printLine() else this.printLine() } } A().invokePrintLine() // Member function A().invokePrintLine(omitThis = true) // Top-level function //sampleEnd() }
Last modified: 22 March 2021