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Questions tagged [extension-function]

Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. Extension methods are a special kind of static method, but they are called as if they were instance methods on the extended type. For client code written in C# and Visual Basic, there is no apparent difference between calling an extension method and the methods that are actually defined in a type.

Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. Extension methods are a special kind of static method, but they are called as if they were instance methods on the extended type. For client code written in C# and Visual Basic, there is no apparent difference between calling an extension method and the methods that are actually defined in a type.

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Kotlin Extension Function

Considering this: MyView.setVisibility(View.VISIBLE) can be simplified to this: inline fun View.setVisible() = apply { visibility = View.VISIBLE } MyView.setVisible() Or this if you prefer: inline infix fun View.vis(vis: Int) = apply { visibility…
johnny_crq
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How do I use an extension function in another class? C#

I've got a couple of extension functions that I want to transfer between classes. I have a class called Helpers.cs that I want to have the following: namespace XYZ { public class Helpers { public static string Encrypt(this string…
natdanimore
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Setup Guice bindings in Kotlin

I want to setup Guice bindings so I created a module in Java that works perfectly: public class CrashLoggerModule extends AbstractModule { @Override public void configure() { bind(CrashLogger.class).to(ConcreteCrashLogger.class); …
Michael
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How to call Kotlin extension function from Groovy code?

I am writing a Gradle plugin in Kotlin language using kotlin-dsl plugin: plugins { `kotlin-dsl` } I have created a plugin class and an extension: class MyPlugin : Plugin { private lateinit var extension: MyPluginExtension …
Vadik Sirekanyan
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Why cannot I create extension to BigDecimal in Kotlin?

I am trying to create an extension as a property and I experimented with an extension function as well, below an example for BigDecimal: val BigDecimal.HUNDRED: BigDecimal get() = TEN.multiply(TEN) fun BigDecimal.HUNDRED_ONE(): BigDecimal { …
Dmytro Chasovskyi
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How to get Dagger2 class property in extension function?

I'm using Dagger2, and would like to use my app's version string in an extension function for a third party class. The app exposes the version as so currently: BuildConfigProvider.kt interface BuildConfigProvider { val version:…
user1114
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Create extension function to assign resource to ImageView with Kotlin

I am starting to work with the Kotlin fun extensions. I've created some that are working correctly for me, but I have one with the ImageView context that doesn't work and I don't understand why. The extension function is this: fun…
Sergio76
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How to supply side effect for RxBinding.textChanges() and preserve it's functionality on client side?

Suppose that i'm writing my own View class, that represents editable field and contains EditText tv_input inside: class EditTextIconItemView : LinearLayout { fun setInputText(text: String?) { with (tv_input) { setText(text) …
Maxim Alov
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Can I use an extension *member* from outside the class?

If I have an extension function for type A declared inside class B: class A class B { fun A.foo() = "Hello" } Can I call this function at all from code that is outside class B? val a = A() val b = B() a.foo() // error: unresolved…
Tobia
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Disambiguating kotlin generic functions

Background: I'm working on a small code generator. I would like to avoid the usual problem of no code hints before the code is actually generated. To solve this I created a general generic dummy method of the sort I intend to generate. inline fun…
Lukasz
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Companion object with extension function in kotlin?

I would like to have extension function and use logger from kotlin-logging and have constants inside companion object. My function: fun String.toFoo(): Foo { logger.debug { "Mapping [$this] to Foo" } if(MY_CONST.equals(this) { …
pixel
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Kotlin - Make extension function accessible in whole project

I have this extension function in a class: fun Double.round2() : Double { return Math.round((this) * 100.0) / 100.0 } I want to reuse this function in another class without the need to duplicate the code. How can I do it? Thank you.
Migue Quintanilla
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Kotlin/Android: Finding all Views of type T recursively

So I have this extension function for ViewGroup : inline fun ViewGroup.allViewsOfType(action: (T) -> Unit) { val views = Stack() afterMeasured { views.addAll((0 until childCount).map(this::getChildAt)) …
Dale Julian
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saxon extension function with NODE_SEQUENCE or ANY_SEQUENCE

I am switching from Saxon 9.3 (PE) to more recent version. I am using Extension functions (with "extends ExtensionFunctionDefinition") I have arguments defined as public SequenceType[] getArgumentTypes() { return new…
Fabien
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Kotlin extension function with Generic doesn't work with Any?

I want to have an extension function from the RealmList class: private inline fun RealmList.saveAll() { this.forEach { item -> Realm.getDefaultInstance().insert(item!! as RealmModel) } } But whenever I use it, this error…
Dale Julian
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