Allow the app to compile again.

android/app/build.gradle.kts

@@ -1,6 +1,8 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 plugins {
     id("com.android.application")
-    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
+    // AGP 9 bundles Kotlin natively - no explicit plugin needed here
     id("dev.flutter.flutter-gradle-plugin")
 }
 
@@ -14,15 +16,15 @@ android {
         targetCompatibility = JavaVersion.VERSION_17
     }
 
-    kotlinOptions {
+    // AGP 9's bundled Kotlin - use the native DSL
-        jvmTarget = JavaVersion.VERSION_17.toString()
+    kotlin {
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_17)
+        }
     }
 
     defaultConfig {
-        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId = "com.hyperling.expense_tracker"
-        // You can update the following values to match your application needs.
-        // For more information, see: https://flutter.dev/to/review-gradle-config.
         minSdk = flutter.minSdkVersion
         targetSdk = flutter.targetSdkVersion
         versionCode = flutter.versionCode
@@ -31,8 +33,6 @@ android {
 
     buildTypes {
         release {
-            // TODO: Add your own signing config for the release build.
-            // Signing with the debug keys for now, so `flutter run --release` works.
             signingConfig = signingConfigs.getByName("debug")
         }
     }

android/build.gradle

@@ -0,0 +1,2 @@
+// Expose Kotlin version for Flutter's plugin validation (AGP 9 bundles Kotlin natively)
+ext.kotlin_version = "2.4.20"

android/gradle.properties

@@ -2,6 +2,8 @@ org.gradle.jvmargs=-Xmx4G -XX:MaxMetaspaceSize=2G -XX:+HeapDumpOnOutOfMemoryErro
 android.useAndroidX=true
 android.enableJetifier=true
 # This builtInKotlin flag was added automatically by Flutter migrator
-android.builtInKotlin=false
+android.builtInKotlin=true
 # This newDsl flag was added automatically by Flutter migrator
 android.newDsl=false
+# Force the Kotlin version resolver in AGP 9 to use our target version
+kotlin.version=2.4.20

android/settings.gradle.kts

@@ -18,9 +18,12 @@ pluginManagement {
 
 plugins {
     id("dev.flutter.flutter-plugin-loader") version "1.0.0"
+
     id("com.android.application") version "9.4.1" apply false
+
+    // This must exist to satisfy Flutter's Gradle plugin validation for AGP 9 bundled Kotlin:
+    // "Error: Your project's Kotlin version (2.2.10) is lower than Flutter's minimum supported version of 2.2.20."
     id("org.jetbrains.kotlin.android") version "2.4.20" apply false
-    id("org.gradle.toolchains.foojay-resolver-convention") version "1.0.0"
 }
 
 include(":app")