Mastering High Performance with Kotlin

Backing properties

If you want to do something that doesn't fit the backing fields scheme (as in the case described earlier), you can use backing properties. Let's rewrite the Button class to use backing properties:

class Button {    private var _text: String? = null    var text: String        set(value) {            println(value)            _text = value        }        get() {            return _text + _text        }    var backgroundColor: Int? = null    var onClickListener: ((Button) -> Unit)? = null    fun printText() {        println(_text)    }}

Here it is decompiled to Java code:

public final class Button {   private String _text;   @Nullable   private Integer backgroundColor;   @Nullable   private Function1 onClickListener;   @NotNull   public final String getText() {      return Intrinsics.stringPlus(this._text, this._text);   }   public ...