Thanks again, Daniele!

The build is now mostly working for Android Kotlin projects. It does print a long warning every time you do anything, and I'll see what I can do about that.

src/main/kotlin/gdx/liftoff/data/files/ProjectFiles.kt

@@ -138,7 +138,28 @@ class SettingsFile(val platforms: Iterable<Platform>) : ProjectFile {
   override fun save(destination: FileHandle) {
     val content = platforms.joinToString(
       prefix =
-      """// A list of which subprojects to load as part of the same larger project.
+      """
+pluginManagement {
+  repositories {
+    google {
+      content {
+        includeGroupByRegex("com\\.android.*")
+        includeGroupByRegex("com\\.google.*")
+        includeGroupByRegex("androidx.*")
+      }
+    }
+    mavenCentral()
+    gradlePluginPortal()
+  }
+}
+dependencyResolutionManagement {
+  repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+  repositories {
+    google()
+    mavenCentral()
+  }
+}
+// A list of which subprojects to load as part of the same larger project.
 // You can remove Strings from the list and reload the Gradle project
 // if you want to temporarily disable a subproject.
 include """,

src/main/kotlin/gdx/liftoff/data/files/gradle/RootGradleFile.kt

@@ -43,53 +43,15 @@ allprojects {
   }
 }
 
-configure(subprojects${if (project.hasPlatform(Android.ID)) {
-    " - project(':android')"
-  } else {
-    ""
-  }}) {
-${plugins.joinToString(separator = "\n") { "  apply plugin: '$it'" }}
-  sourceCompatibility = ${project.advanced.javaVersion}
-
-  // From https://lyze.dev/2021/04/29/libGDX-Internal-Assets-List/
-  // The article can be helpful when using assets.txt in your project.
-  tasks.register('generateAssetList') {
-    inputs.dir("${'$'}{project.rootDir}/assets/")
-    // projectFolder/assets
-    File assetsFolder = new File("${'$'}{project.rootDir}/assets/")
-    // projectFolder/assets/assets.txt
-    File assetsFile = new File(assetsFolder, "assets.txt")
-    // delete that file in case we've already created it
-    assetsFile.delete()
-
-    // iterate through all files inside that folder
-    // convert it to a relative path
-    // and append it to the file assets.txt
-    fileTree(assetsFolder).collect { assetsFolder.relativePath(it) }.sort().each {
-      assetsFile.append(it + "\n")
-    }
-  }
-  processResources.dependsOn 'generateAssetList'
-
-  compileJava {
-    options.incremental = true
-  }${if (plugins.contains("kotlin")) {
-    """
-  compileKotlin.compilerOptions.jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_${
-    if (project.advanced.javaVersion.removePrefix("1.") == "8") {
-      "1_8"
-    } else {
-      project.advanced.javaVersion.removePrefix("1.")
-    }})
-  """
-  } else {
-    ""
-  }}
-}
-
 subprojects {
   version = '${'$'}projectVersion'
   ext.appName = '${project.basic.name}'
+}
+
+eclipse.project.name = '${project.basic.name}' + '-parent'
+"""
+}
+/*
   repositories {
     mavenCentral()
     maven { url 'https://s01.oss.sonatype.org' }
@@ -104,8 +66,4 @@ subprojects {
     ""
   }}
   }
-}
-
-eclipse.project.name = '${project.basic.name}' + '-parent'
-"""
-}
+ */

src/main/kotlin/gdx/liftoff/data/languages/Kotlin.kt

@@ -17,7 +17,6 @@ class Kotlin : Language {
   override val version = "2.0.21"
 
   override fun initiate(project: Project) {
-    project.rootGradle.buildDependencies.add("\"org.jetbrains.kotlin:kotlin-gradle-plugin:\$kotlinVersion\"")
     project.rootGradle.plugins.add(id)
     project.platforms.values.forEach { project.files.add(SourceDirectory(it.id, path("src", "main", "kotlin"))) }
     if (project.hasPlatform(Android.ID)) {

src/main/kotlin/gdx/liftoff/data/platforms/Android.kt

@@ -148,8 +148,9 @@ buildscript {
     classpath 'com.android.tools.build:gradle:8.5.2'
   }
 }
-${plugins.joinToString(separator = "\n") { "apply plugin: '$it'" }}
-${if (latePlugin)"apply plugin: \'kotlin-android\'" else ""}
+plugins {
+  id "com.android.application" version "8.4.2"
+  ${if (latePlugin) "  id 'org.jetbrains.kotlin.android' version '2.0.21'\n" else ""}}
 
 android {
   namespace "${project.basic.rootPackage}"
@@ -207,11 +208,6 @@ android {
     }}
 }
 
-repositories {
-  // needed for AAPT2, may be needed for other tools
-  google()
-}
-
 configurations { natives }
 
 dependencies {

src/main/kotlin/gdx/liftoff/data/platforms/Core.kt

@@ -19,7 +19,7 @@ class Core : Platform {
   override val order = ORDER
   override val isStandard = false
   override fun createGradleFile(project: Project): GradleFile {
-    return CoreGradleFile()
+    return CoreGradleFile(project)
   }
 
   override fun initiate(project: Project) {
@@ -31,15 +31,57 @@ class Core : Platform {
 /**
  * Gradle file of the core project. Should contain all multi-platform dependencies, like "gdx" itself.
  */
-class CoreGradleFile : GradleFile(Core.ID) {
+class CoreGradleFile(val project: Project) : GradleFile(Core.ID) {
   init {
     addDependency("com.badlogicgames.gdx:gdx:\$gdxVersion")
   }
 
   override fun getContent(): String {
-    return """[compileJava, compileTestJava]*.options*.encoding = 'UTF-8'
+    return """
+plugins {
+  id "java-library"
+${if ( project.rootGradle.plugins.contains("kotlin")) "  id 'org.jetbrains.kotlin.jvm' version '2.0.21'\n" else ""}}
+
+  // From https://lyze.dev/2021/04/29/libGDX-Internal-Assets-List/
+  // The article can be helpful when using assets.txt in your project.
+  tasks.register('generateAssetList') {
+    inputs.dir("${'$'}{project.rootDir}/assets/")
+    // projectFolder/assets
+    File assetsFolder = new File("${'$'}{project.rootDir}/assets/")
+    // projectFolder/assets/assets.txt
+    File assetsFile = new File(assetsFolder, "assets.txt")
+    // delete that file in case we've already created it
+    assetsFile.delete()
+
+    // iterate through all files inside that folder
+    // convert it to a relative path
+    // and append it to the file assets.txt
+    fileTree(assetsFolder).collect { assetsFolder.relativePath(it) }.sort().each {
+      assetsFile.append(it + "\n")
+    }
+  }
+  processResources.dependsOn 'generateAssetList'
+
+  compileJava {
+    options.incremental = true
+  }${if (project.rootGradle.plugins.contains("kotlin")) {
+      """
+  compileKotlin.compilerOptions.jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_${
+        if (project.advanced.javaVersion.removePrefix("1.") == "8") {
+          "1_8"
+        } else {
+          project.advanced.javaVersion.removePrefix("1.")
+        }})
+  """
+    } else {
+      ""
+    }}
+
+[compileJava, compileTestJava]*.options*.encoding = 'UTF-8'
 eclipse.project.name = appName + '-core'
 
+sourceCompatibility = ${project.advanced.javaVersion}
+
 dependencies {
 ${joinDependencies(dependencies, "api")}
   if(enableGraalNative == 'true') {

src/main/kotlin/gdx/liftoff/data/platforms/Lwjgl3.kt

@@ -145,8 +145,7 @@ buildscript {
 plugins {
   id "io.github.fourlastor.construo" version "1.4.1"
   id "application"
-}
-${if (project.rootGradle.plugins.contains("kotlin")) "apply plugin: 'org.jetbrains.kotlin.jvm'\n" else ""}
+${if (project.rootGradle.plugins.contains("kotlin")) "  id 'org.jetbrains.kotlin.jvm' version '2.0.21'\n" else ""}}
 
 import io.github.fourlastor.construo.Target