Download Website With content On Android Device I’m Having Trouble finding the best solution to design a signage app, which includes downloading a specific web page with all content (html, css, js, images, videos) sent from the server using an API, to a local folder on the device, and then load this website in a webview for offline use. is there any solution for that ? Thanks 1 post - 1 participant Read full topic

General-purpose question about pattern-matching Hi all, I’m really confused about the pattern-matching concept. I read in mutiple places that kotlin does not support pattern matching (last example I’ve read is this Arrow issue). However, When looking at this document by M. Goetz talking about possible pattern matching in Java, It looks to me that Kotlin...

How to call super extension functions I want to override an extension function and want to call super implementation. here is the example source code and link to the playground. open class TestA {} open class Test1 { open fun T.function1(): T = apply { // do something } open fun T.function2(): T = apply { // do something } } class Test2 : Test1() { override fun T.function1(): T = apply { super.function1() // compile error at here: Unresolved reference. // do somethings or...

Inlining Arrays of Lambdas Suppose you want to sort a list of objects by certain values in order: data class Data(val a: Boolean, val b: Boolean, val c: Boolean, val d: Int) The easiest way to do it is to just list the properties you want to sort by in lambdas: val comparatorLambdas = compareBy({ it.a }, { it.b }, { it.c }, { it.d }) Alternatively, you could list the properties in a compareBy/thenBy chain: val comparatorChain = compareBy { it.a } .thenBy { it.b } .thenBy { it.c }...

Reified type parameters for inline classes As far as I know, this should be possible. inline class Blah(val name: String) { fun bloh(): String { return "${T:class.simpleName} $name" } } I’m not sure how much needs to be explained, it’d work similar to reified type parameters in inline functions. This is currently not possible but it’d make sense to implement it as a feature. 1 post - 1 participant <a...

StringBuilder.indices not updated after char removal Hello everyone. I’m new to Kotlin and I’m still playing with it to learn it. As an exercise, I was writing a function to check if two strings are an anagram of each other. To implement this my idea was to go through the first string and, for each character, delete the first occurrence of that character from the second string. I also delete spaces since I want to ignore them. Then if the second string is empty the two strings are anagrams, otherwise not. This is my function: fun...

How can I add space to the text of myHow to send a website to a second activity in kotlin? I am trying to create an application that allows sending any website as data, but when I write the address it does not load in the second activity. MainActivity bt_ir.setOnClickListener { val sitio = pt_sitio.text.toString() val inten = Intent (this, MainActivity2_Webview::class.java) inten.putExtra("Clave", sitio) startActivity(inten) } Second Activity val intent = intent val name = intent.getStringExtra("Clave")...

How can I do 'qualified superclass constructor invocation' in Kotlin? I’m looking for a way to extend a non-static nested class from Kotlin. From the JLS Chapter 8 Example 8.8.7.1-1. Qualified Superclass Constructor Invocation // Java Code class Outer { class Inner {} } class ChildOfInner extends Outer.Inner { ChildOfInner() { (new Outer()).super(); } } I tried this: // Kotlin Code class Outer { open inner class Inner {} } val outer = Outer() class...

How to have round robin effect for many coroutines execution sequence? Imagine you have Coroutine of type A. Coroutine of type B. Coroutine of type C. You launch very quickly 1000 A, then 1000 B, then 1000 C coroutines == 3000 coroutines. How to ensure that on each Thread coroutines will be executed in round robin order: A, then B, then C A, then B, then C A, then B, then C A, then B, then C … Currently it more looks like they will be executed like: 1000 A 1000 B 1000 C Am I correct ?? 1 post - 1 participant <a...

More compact equals? Now android studio generates method equals as below: class Current(val id: Long) { override fun equals(other: Any?): Boolean { if (this === other) return true if (javaClass != other?.javaClass) return false other as Current if (id != other.id) return false return true } } I often rewrite it to: class Compact(val id: Long) { override fun equals(other: Any?): Boolean { return other...

Unresolved reference (unused import) I am writing my first project and get this error Unresolved reference: makeText this work without import: import kotlinx.android.synthetic.main.activity_main.* and without function countMe, because...

Conversion of values of type Strings Hello, I’m having trouble converting values ​​of type String to Int example, I want to convert this String to int would be : var vlConvResult: String = “10 + 1-2” lxl: Integer = Integer (vlConvResult) System.out.println (lxl) // result 9 I did like this var lvx = tfcont.getText () var lxl: Integer = Integer (lvx) System.out.println (lvx.toString ()) 1 post - 1 participant <a...

Proper way to use a constructor to manually initialize a list in a ViewModel class I want to manually build a custom list in my constructor (maybe somewhere else if you have a suggestion) that populates my MutableList variable once the class is created. class MaleActivityViewModel : ViewModel() { var servicePosition: Int = 0 var priceLowEnd: Int = 0 var priceHighEnd: Int = 0 val currency: String = Resources.getSystem().getString(R.string.currency) private lateinit var serviceTextListMale: List init { val haircut: String =...

Add parameters in constructor for viewmodel? I have the following ViewModel with a second constructor: class MaleActivityViewModel() : ViewModel() { val currency: String = Resources.getSystem().getString(R.string.currency) private lateinit var serviceTextListMale: List private lateinit var serviceImageAdapter: CarouselPicker.CarouselViewAdapter constructor(activity: Context) : this() { //Text list of all the services val haircut: String = Resources.getSystem().getString(R.string.service_haircut)...

Context in ViewModel My class that extends ViewModel() has a private context in it. Is it bad for memoryleaks? I didn’t understand the documentation what they were saying > class MaleActivityViewModel : ViewModel() { > > private lateinit var mContext: Context > > fun getContext(context: Context){ > mContext = context > } > } 1 post - 1 participant <a href="https://discuss.kotlinlang.org/t/context-in-viewmodel/18285">Read full...

Specifying external annotations for the compiler It seems like there used to be a way to produce compile time nullability errors using external annotations, as described in the following pages: External Annotations https://blog.jetbrains.com/kotlin/using-external-annotations/ <a...

Use and val initialization I stumbled upon something that thoroughly confused me. The following code is not legal: val i: Int AutoCloseable { }.use { i = 5 } // Captured values initialization is forbidden due to possible reassignment Whereas this is fine: val i: Int AutoCloseable { }.let { i = 5 } // also, apply, run ... Both of these methods return block(this): public inline fun T.use(block: (T) -> R): R { var exception: Throwable? = null try { return block(this) } catch (e: Throwable) {...

Kotlin Native Compilation Time Hi all, I’m new to Kotlin Native, I just did an ‘Hello World’ and it took about 4s to compile, so I have the following questions: is this normal or there is something wrong with my system? is Kotlin Native production ready? fun main() { print("hello world") } kotlinc-native SampleLinux.kt -o hello btw I’m using Ubuntu 20.04 / 16GB ram / iCore 5 Thanks 1 post - 1 participant <a href="https://discuss.kotlinlang.org/t/kotlin-native-compilation-time/18307">Read...

Change .konan folder location When building K/N using Gradle the default path for the caches is ~/.konan. Is it possible to change that path? For example similarly to how Gradle cache fodler can be set using the env variable GRADLE_USER_HOME. 1 post - 1 participant Read full topic

Kotlin on jvm 14 Hi. I have the nex error when a I try to compile my spring boot application using kotlin, the project is using java 14 Failed to execute goal org.jetbrains.kotlinkotlin maven plugin1.3.72:compile (compile) on project X: Compilation failure Unknown JVM target version: 14 Supported versions: 1.6, 1.8, 9, 10, 11, 12, 13 Do you know if kotlin is already supported by java 14 ? 1 post - 1 participant <a href="https://discuss.kotlinlang.org/t/kotlin-on-jvm-14/18311">Read...

Redimensionarlas imágenes Hola que tal ustedes saben una forma de redimensionar imágenes tomadas desde el teléfono para que no pesen mucho y se ponga lenta la app 1 post - 1 participant Read full topic

Finding the "type" of a variable Hi, I seem to have stepped into a smallproblem for which I do not find the solution by reading all tutorials / docs at the jetbrains side: I have created a very small fun that shall return for a given Type a default value of that same type: @JvmStatic inline fun defaultOf() : T { return convertDefaultValues.get(T::class) as T } Its inside of a class and used as a "static class method, for example: … if (value::class == toType) return value val defaultValue = if (default != Unit) default else...

Returning a Deferred&lt;Result&lt;T&gt;&gt; from a Coroutine Async method We have recently introduced Coroutines to our codebase and have a method similar to the signature below for one of the asynchronous operations we need to perform: private fun fetchSomethingFromServerAndReturnItsLocalPath(somethingId: String): Deferred We are experiencing problems with this approach when the Result is set to indicate failure in the resulting async Coroutine this method runs. It appears that when the Coroutine returns the exception is thrown rather the Deferred object being...

Having fun with Kotlin and Unicode fun main(args: Array) { val condition = args.isEmpty() val v0 = condition ʔ "true" ː "false" val v1 = condition ʔ "true" ː { "false" } val v2 = condition ʔ { "true" } ː "false" val v3 = condition ʔ { "true" } ː { "false" } val a = (1 ᐸᐸ 31) ᛁ 0x0f } class IfPart(val cond: Boolean, val result: T?) { infix fun ː(elseBlock: () -> T): T = if (cond) result!! else elseBlock() infix fun ː(elseBlock: T): T = if (cond) result!! else elseBlock } infix fun...

Hellow comunity! how can send image to server in kotlin using the library volley i have a webservice in php a need seve the image in my server, when de user touch the botton 1 post - 1 participant Read full topic

Extension Function as supertype Warning: possible noob question

Java reflection and Kotlin primitive types IDEA warns me that Java boxed types shouldn’t be used, and that I should use respective Kotlin types instead. It works most of the time, but sometimes leads to unexpected results. Here’s an example. class Property private constructor(val type: Class) { companion object { @JvmField val STRING_PROPERTY = Property(String::class.java) @JvmField val INT_PROPERTY = Property(Int::class.java) @JvmField val LONG_PROPERTY = Property(Long::class.java) } } class...

State of WebAssembly in Kotlin Hi, everybody! I just wanted to clarify the current situation of supporting WebAssembly in Kotlin. We are working on a dedicated Kotlin to WebAssembly compiler backend. So all works on wasm support in Kotlin/Native (through LLVM) were suspended. For the new compiler backend, we have set the following goals: produce small binaries – to achieve it we decided don’t use own memory manager and use builtin one instead (see GC proposal); fast...

Setting an if else statement ##Question I want to setup an if else statement that checks the value of a variable. ##Details However, something different is that, it should check the value between 2 numbers ##Example val a=6 How do I set the statement up that it checks if x is 3

Cannot run kotlinc Hello everyone. I want to run kotin on VSCODE. After I installed kotlinc, the following error appeared when I ran the kotlinc -version command: kotlinc-jvm -version info: kotlinc-jvm 1.3.31 (JRE 1.8.0_181-_2018_10_18_16_01-b00) exception: java.lang.ExceptionInInitializerError at sun.nio.fs.Util.split(Unknown Source) at sun.nio.fs.WindowsFileSystem.(Unknown Source) at sun.nio.fs.WindowsFileSystemProvider.(Unknown Source) at sun.reflect.NativeConstructorAccessorImpl.(Unknown Source) at...