kotlinlang #multiplatform

dispatcher and I can’t tell if the network request is running on the main thread or a background thread. Does Ktor handle running a single background thread for me?

Cicero

11/18/2020, 9:31 PM

A small weird question, have you ever stumbled into adding a library and then suddenly your project is not recognized anymore as a Kotlin project? It took me a while to realize it was because of a library, ktor-client-gson specifically, and, when working with android, I didn't really stumbled on this before

Nikita Khlebushkin

11/18/2020, 10:15 PM

Hello! I have a KMM library created and developed from KMM template less than a month ago. It has the following structure:

mobile-shared [SharedLogic]
|____ ModuleShared
|____ TestAndroidApp
|____ TestIosApp

I can build and compile KMM library, assemble .jar, Cocoapods - no problem here. Lately I've been trying to add this project as a module dependency to an Android project, which used to have the following structure:

MyApp
|____ app

and now has the following structure:

MyApp
|____ app
|____ mobile-shared [SharedLogic]
|____|____ ModuleShared
|____|____ TestAndroidApp
|____|____ TestIosApp

How I was trying to do it: Option 1: MyApp/settings.gradle.kts:

pluginManagement {
    repositories {
        gradlePluginPortal()
        google()
        jcenter()
        mavenCentral()
    }
    resolutionStrategy {
        eachPlugin {
            if (requested.id.namespace == "com.android" || requested.id.name == "kotlin-android-extensions") {
                useModule("com.android.tools.build:gradle:4.0.1")
            }
        }
    }
}

include(":app")
include(":SharedLogic")
project(":SharedLogic").projectDir = File("mobile-shared")
include(":SharedLogic:ModuleShared")

MyApp/app/build.gradle.kts:

...
android {
    dependencies {
        implementation(project(":SharedLogic:ModuleShared"))

Option 2: MyApp/settings.gradle.kts:

pluginManagement {
    repositories {
        gradlePluginPortal()
        google()
        jcenter()
        mavenCentral()
    }
    resolutionStrategy {
        eachPlugin {
            if (requested.id.namespace == "com.android" || requested.id.name == "kotlin-android-extensions") {
                useModule("com.android.tools.build:gradle:4.0.1")
            }
        }
    }
}

include(":app")
include(":ModuleShared")
project(":ModuleShared").projectDir = File("mobile-shared/ModuleShared")

MyApp/app/build.gradle.kts:

...
android {
    dependencies {
        implementation(project(":ModuleShared"))

Error I encounter:

A problem occurred configuring project ':SharedLogic:ModuleShared'.
* Where:
Build file '/home/xlebnick/projects/MyApp/mobile-shared/ModuleShared/build.gradle.kts' line: 40

* What went wrong:
This version of the kotlin-serialization Gradle plugin is built for a newer Kotlin version. Please use an older version of kotlin-serialization or upgrade the Kotlin Gradle plugin version to make them match.

In ModuleShared/build.gradle.kts:

plugins {
    kotlin("plugin.serialization") version "1.4.10"
}

In mobile-shared/build.gradle.kts:

buildscript {
    repositories {
        gradlePluginPortal()
        jcenter()
        google()
        mavenCentral()
    }
    dependencies {
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.10")
        classpath("com.android.tools.build:gradle:4.1.0")
    }
}

And in MyApp/build.gradle.kts:

uildscript {
    apply(from = "versions.gradle.kts")
    val kotlinVersion: String by extra // 1.4.10
    val rootClasspath: List<String> by extra

    repositories {
        mavenCentral()
        google()
        jcenter()
        maven("<https://plugins.gradle.org/m2/>")
        maven("<https://maven.fabric.io/public>")
    }

    dependencies {
        classpath(kotlin("gradle-plugin", version = kotlinVersion))
        for (rc in rootClasspath) {
            classpath(rc)
        }
    }
}

What am I doing wrong? P.S. Found this issue, but it doesn't help at all

Philip Dukhov

11/18/2020, 10:24 PM

Hi! I have a multiplatform module containing a server, with one kotlin multiplatform dependency module . Running it from main function with play button produces following error:

Error: Could not find or load main class com.well.server.ApplicationKt

I’ve found a solution to run it, using following task:

task<JavaExec>("run") {

main = "com.well.server.ApplicationKt"

val jvm by kotlin.targets.getting

val main: KotlinCompilation<KotlinCommonOptions> by jvm.compilations

val runtimeDependencies = (main as KotlinCompilationToRunnableFiles<KotlinCommonOptions>).runtimeDependencyFiles

classpath = files(main.output.allOutputs, runtimeDependencies)

One of the minuses - I can’t debug server and run an other module, because server starts running as part of task, and task progress remains 92 until I abort it. Is there a better solution? But the main goal right now is to deploy the server. Following the official guide, I tried this code:

tasks.create("stage") {

dependsOn(tasks.getByName("installDist"))

application {

mainClassName = "ApplicationKt"

distributions {

main {

contents {

from("$buildDir/libs") {

rename("${rootProject.name}-jvm", rootProject.name)

into("lib")

tasks.getByName<JavaExec>("run") {

`classpath(tasks.getByName<Jar>("jvmJar")) // so that the JS artifacts generated by

jvmJar

can be found and served`

But

./gradlew :server:run

returns

Could not find or load main class ApplicationKt

error, and

:server:jvmJar

finishes without errors but doesn’t seems to produce the output

Amritansh

11/18/2020, 11:13 PM

Hello, I am working on a KMM library which requires me to get these values from iOS and Android Devices. • appVersion • connection type: Wifi or cellular • Carrier • Os version • Device model What will be the best way to approach this? Should I ask them at the time of initialization in the Apps or is there another way to get them internally from the KMM project? Happy to elaborate more if this does not make sense.

william

11/19/2020, 1:05 AM

has anyone tried using

kotlin.Result

in multiplatform? i'm not having any luck using it with

kotlin {
    targets.all {
        compilations.all {
            kotlinOptions {
                freeCompilerArgs = freeCompilerArgs + "-Xallow-result-return-type"
            }
        }
    }
}

I still get the message saying I can't use result as a return type

william

11/19/2020, 1:45 AM

alternatively does anyone know of multiplatform Result libraries? i haven't been able to find one supporting jvm and ios

Rengu N

11/19/2020, 5:26 AM

Hello Team - Do anyone know how to make build variants for KMP especially for native iOS

Sergio Casero

11/19/2020, 11:05 AM

Hello guys, I have a kmp module with JVM target, the problem is that the IDE doesn't recognize it in one of my modules, it doesn't have any sense because, in fact, If I compile the project by manual putting the imports, it works perfectly, but the IDE doesn't recognize it, any solutions? I've included the dependency with

implementation(project(":accesscontrol"))

This is my 6th kmp project and I never get this issue. I have 3 JVM modules and works on 2 of them perfectly. I've tried cleaning the project, invalidating the cache, restarting the PC... When I execute

./gradlew run

I can see that common related tasks are executed, and I can see the jar inside the build folder

Jeremias Nunez

11/19/2020, 2:16 PM

Hi All! I've successfully integrated a KMP module into an existing iOS app, but I'm having an issue with the difference between the generated Obj-C class name (Prefix+ClassName) and the Swift name (ClassName) of one of my classes. When I try to iterate over an array of such classes I'm getting this error: Precondition failed: NSArray element failed to match the Swift Array Element type
Expected Movie but found SharedMovie: file Swift/ArrayBuffer.swift, line 354
My Movie class is defined like this:

@Serializable
data class Movie(
    val name: String,
    val tone: String,
    val light: String,
    val url: String,
    val order: Int,
    val version: Int
)

I found this issue but it doesn't provide any possible solution: https://github.com/JetBrains/kotlin-native/issues/2830

Cicero

11/20/2020, 8:56 AM

Yesterday I imported both my old android project and iOS to my new KMM projetect ❤️. But honestly the current public documentation is not good. If I didn't had some medium posts to help me out I would have failed, or taken way longer. If you would do this migration into KMM, which sources do you use? Do you know the process back and forth? Am I too green? I would like to hear other people experiences. I feel like there is still space for a good guide for it, with a video and all, I'm probably gonna put my hands on 🙃

mmaillot

11/20/2020, 10:04 AM

Hi ! I created a project with ktor server. I have a frontend with typescript. I’m looking for a solution to share API data between projects. My idea is to create a module in my ktor project which contains data class (using kotlinx.serialization) and API call (using ktor client). I want to generate the API calls for my frontend in typescript. Can I do that with MPP ? Do you have some links, tips ?

Tristan Hamilton

11/20/2020, 12:37 PM

Hello! Looking to add iOS target for kotlin-result lib: https://github.com/michaelbull/kotlin-result/pull/23 Main issue up to now is not having a macOS machine to compile and publish with. Someone just pointed out that we could use a free github actions macos env, however if we need to install full xcode that will break the free storage limit. If we could just install the xcode cli tools, seems we would be ok. So when I originally went to add this I definitely read some doc that I believe mentioned needing full xcode installed (it used to mention something about it here: https://kotlinlang.org/docs/reference/building-mpp-with-gradle.html#using-kotlinnative-targets but that page is now gone). Can anyone here confirm if xcode cli tools installed is enough to build iOS targets for multiplatform library?

Azur Haljeta

11/20/2020, 5:55 PM

Is there any recommended approach to make WebSockets work on both Android and iOS, since Ktor WebSockets are still not supported on Kotlin Native?

Ola Adolfsson

11/21/2020, 7:44 PM

Hi, is there anyone else having isses with the absolute paths in the npm packages creaeted by kotlin 1.4.* when it comes to consuming them in a “real” nodejs project? https://discuss.kotlinlang.org/t/local-dependencies-in-package-json-of-js-mpp-projects/19260

👀 1

Cicero

11/21/2020, 9:13 PM

So, hello people, I’m trying to do something that I expected to be rather simple and it’s not working. I have this object:

data class LoginModel(
    @SerialName("username")
    val username: String?,
    @SerialName("password")
    val password: String?,
    @SerialName("userType")
    val userType: String = "PROFESSIONAL"
)

With the serialisers and all, when I try to access it in swift I find this: - (instancetype)initWithUsername:(NSString * _Nullable)username password:(NSString * _Nullable)password userType:(NSString *)userType And when I try to use it on my code it kinda foces me to put something on my variable with a pre defined value, like this: let login = common.LoginModel(username: emailTextfield.text, password: passwordTextField.text, userType: “PROFESSIONAL”) I can live with this but I would like to know if there is an immediate solution. PS: It works fine on android, as intended. How default values work on swift: https://docs.swift.org/swift-book/LanguageGuide/Functions.html

Skolson5903

11/22/2020, 1:39 AM

Saw 1.4.20 is out, tried upgrading a project from 1.4.20-RC that also uses the kotlinx atomic plugin

buildscript {
        ...
        classpath("org.jetbrains.kotlinx:atomicfu-gradle-plugin:0.14.4")
    }

Module build.gradle.kts:

plugins {
        ...
        id("kotlinx-atomicfu")
     }

After the upgrade the IDE (Android Studio 4.1) shows this import in error, but gradle build still works:

import kotlinx.atomicfu.atomic

In the IDE, the ending "atomic" is red as if it isn't in the dependencies, but gradle builds OK and tests run. Previously I had seen IDE-bad vs Gradle-good build issues in this project on the "java" package, but adding this to gradle.properties fixed that:

kotlin.mpp.enableGranularSourceSetsMetadata=true

That option is still set and doesn't help this new atomic issue. Anyone else seen this with 1.4.20? I'm still researching. Thanks in advance for any info...

napperley

11/22/2020, 2:59 AM

Looks as though I have stumbled on a bug where the dependencies for the first JVM module are applied, but not for the second one. IntelliJ is providing the option to include a library from classpath in the second JVM module, which the IDE shouldn't be doing with a platform module.

Hai Tran

11/23/2020, 9:02 AM

What’s best way to implement multi-language in KMM? • split according to specific platforms • combine a common definition file(.kt, .xml,…)

Cicero

11/23/2020, 11:51 AM

Today I stumbled upon this article and there is a topic about compilation. Do we still suffer from this in KMM? https://medium.com/xorum-io/crafting-and-publishing-kotlin-multiplatform-library-to-bintray-cbc00a4f770 https://github.com/xorum-io/ReKamp

Jérôme Gully

11/23/2020, 5:52 PM

Hi, just got that, i find no communication in release note about that. BTW it's still compile and run on my Linux machine.

11/23/2020, 7:09 PM

Hello, is there any good tutorial about how to integrate

shared.framework

(which is exported from :*packForXcode*) via a

cococapods

into an existing App, without linking the App-project with the MPP-project (like in the Android Studio example)? We need to have the MPP-project separate from the iOS App and only use

cocoapods

to link the (prebuild) dependency. Every example I find either directly invokes :packForXcode from Xcode build-phases or uses

cocoapods

just to reference to the relative-path of the framework.

Amritansh

11/23/2020, 9:48 PM

Hello, How can we create a Singleton in Kotlin which takes some parameters? The reason I am asking this in this channel is because in kotlin native we can not have var in an object class unless you annotate it with ThreadLocal. I am not sure how to save value in a member variables of a singleton object class.

russhwolf

11/23/2020, 10:25 PM

What’s the state of support for the

kotlin.mpp.enableCompatibilityMetadataVariant

flag for library authors to avoid compatibility issues with projects that don’t enable heirarchical project support? I see it in the JB libs, but can I use it or should I avoid it?

Vincent Chen

11/24/2020, 6:11 AM

message has been deleted

Jérôme Gully

11/24/2020, 9:55 AM

Hi, How do you encode/decode base64 in common code ? You go down to the android/ios specific sourceset ? I found that but it's seems forgotten https://github.com/Kotlin/kotlin-examples/pull/90

Paul Woitaschek

11/24/2020, 10:30 AM

We have created a library that is built on our CI linux machine. That library has no specific ios dependencies and all the logic resides in commonMain. Am I correct that I can't use that library at all unless I buy a mac and add an empty nativeMain source set and publish that?

Philip Dukhov

11/24/2020, 4:47 PM

I wanna share env file among ios/android/server modules. I’ve created

xcconfig

file in Xcode, and shared it with android using

android.buildTypes.resValue

. How can I do the same with a KMP shared module?

Frankablu

11/24/2020, 5:15 PM

I'm doing a port of a Kotlin/JVM to multi platform (JVM/Js/Native), is there any libraries I can call on for basic file i/o aka read a text file to a string and write a text file to a string (i assume it exist but I can't find it). Also I've got concurrency in the JVM version using worker threads (read jobs from a task queue and write results to a result queue), any multi-platform equivalent library?

why

11/24/2020, 6:37 PM

Hi.. I’m in a need of a weakly referenced object like the one in java (WeakReference) how can I achieve that in KMP? In other words I need some objects to be cleared by the garbage collector when it’s weakly reachable