feat: modernize Android build toolchain

android/build.gradle.kts

@@ -0,0 +1,124 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+buildscript {
+    val kotlinVersion = "2.3.20"
+    repositories {
+        google()
+        mavenCentral()
+        // Only needed to resolve ktfmt below (development/CI-only, gated by -Pktfmt).
+        if (providers.gradleProperty("ktfmt").isPresent) {
+            maven { url = uri("https://plugins.gradle.org/m2/") }
+        }
+    }
+
+    dependencies {
+        classpath("com.android.tools.build:gradle:8.8.1")
+        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion")
+        // ktfmt (Kotlin formatter) is a development/CI-only tool. Pulling it onto the classpath
+        // (and applying it below) is gated behind -Pktfmt so it is never forced on apps that
+        // depend on this plugin. Enabled by `melos run format:android`.
+        if (providers.gradleProperty("ktfmt").isPresent) {
+            classpath("com.ncorti.ktfmt.gradle:plugin:0.21.0")
+        }
+    }
+}
+
+plugins {
+    id("com.android.library")
+}
+
+group = "com.google.maps.flutter.driver"
+version = "1.0-SNAPSHOT"
+
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+// Apply the Kotlin Gradle Plugin (KGP) only when consumed by AGP < 9. AGP 9+ ships built-in Kotlin,
+// so applying KGP there is unnecessary and triggers a Flutter deprecation warning. Keeping it
+// conditional preserves compatibility for apps still on AGP 8.
+// https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-plugin-authors#supporting-flutter-versions-earlier-than-3-44
+val agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.substringBefore('.').toInt()
+if (agpMajor < 9) {
+    apply(plugin = "org.jetbrains.kotlin.android")
+}
+
+// ktfmt is applied only for development/CI formatting (-Pktfmt), so it is never forced on apps
+// that depend on this plugin. Run via `melos run format:android` (which passes -Pktfmt).
+if (providers.gradleProperty("ktfmt").isPresent) {
+    apply(plugin = "com.ncorti.ktfmt.gradle")
+    // Configured dynamically (no compile-time type reference) so this script still compiles when
+    // ktfmt is absent from the classpath, i.e. for apps that depend on this plugin.
+    extensions.getByName("ktfmt").withGroovyBuilder { "googleStyle"() }
+}
+
+android {
+    namespace = "com.google.maps.flutter.driver"
+
+    compileSdk = 36
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    sourceSets {
+        getByName("main") {
+            java.srcDirs("src/main/kotlin")
+        }
+        getByName("test") {
+            java.srcDirs("src/test/kotlin")
+        }
+    }
+
+    defaultConfig {
+        minSdk = 26
+    }
+
+    testOptions {
+        unitTests {
+            isIncludeAndroidResources = true
+            all {
+                it.testLogging {
+                    events("passed", "skipped", "failed", "standardOut", "standardError")
+                    showStandardStreams = true
+                }
+                it.outputs.upToDateWhen { false }
+            }
+        }
+    }
+}
+
+// Configure the Kotlin JVM target via the compilerOptions DSL (replaces the deprecated
+// android.kotlinOptions block). Configured through the extension so it works whether the Kotlin
+// plugin is applied conditionally (AGP < 9) or provided by AGP's built-in Kotlin (AGP 9+). The
+// static `kotlin { }` accessor is not generated for imperatively-applied plugins.
+project.extensions.configure(org.jetbrains.kotlin.gradle.dsl.KotlinAndroidProjectExtension::class.java) {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}
+
+dependencies {
+    implementation("com.google.android.libraries.mapsplatform.transportation:transportation-driver:7.0.0")
+    implementation("androidx.startup:startup-runtime:1.2.0")
+    testImplementation("org.jetbrains.kotlin:kotlin-test")
+    testImplementation("io.mockk:mockk:1.13.9")
+    testImplementation("junit:junit:4.13.2")
+    testImplementation("org.robolectric:robolectric:4.11.1")
+}

android/settings.gradle → android/settings.gradle.kts

@@ -1,4 +1,4 @@
-// Copyright 2023 Google LLC
+// Copyright 2026 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -12,4 +12,4 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-rootProject.name = 'google_driver_flutter'
+rootProject.name = "google_driver_flutter"

example/android/app/build.gradle.kts

@@ -41,16 +41,12 @@ android {
     compileSdk = flutter.compileSdkVersion
     ndkVersion = "28.2.13676358"
 
-    compileOptions {        
+    compileOptions {
         // Flag to enable support for the new language APIs
         isCoreLibraryDesugaringEnabled = true
-        // Sets Java compatibility to Java 11
-        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_11
-    }
-
-    kotlinOptions {
-        jvmTarget = JavaVersion.VERSION_11.toString()
+        // Sets Java compatibility to Java 17
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
     }
 
     // Set this to the languages you actually use, otherwise you'll include resource strings
@@ -105,6 +101,14 @@ android {
     }
 }
 
+// Configure the Kotlin JVM target via the compilerOptions DSL (replaces the deprecated
+// android.kotlinOptions block).
+kotlin {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}
+
 flutter {
     source = "../.."
 }

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.13-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.3-all.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

example/android/settings.gradle.kts

@@ -33,7 +33,7 @@ pluginManagement {
 plugins {
     id("dev.flutter.flutter-plugin-loader") version "1.0.0"
     id("com.android.application") version "8.13.0" apply false
-    id("org.jetbrains.kotlin.android") version "2.1.0" apply false
+    id("org.jetbrains.kotlin.android") version "2.3.20" apply false
     id("com.google.android.libraries.mapsplatform.secrets-gradle-plugin") version "2.0.1" apply false
 }
 

melos.yaml

@@ -73,7 +73,7 @@ scripts:
     run: |
       if [ -d "example" ]; then cd example; fi && \
         if [ ! -f android/gradlew ]; then flutter build apk --config-only; fi &&
-        cd android && ./gradlew ktfmtFormat
+        cd android && ./gradlew -Pktfmt ktfmtFormat
     exec:
       concurrency: 1
       failFast: true