Updated to Android Studio 3.0. Getting a “Kotlin not configured” error

Question

I just updated to Android Studio 3.0 and I\'m getting this error with an existing project:

Kotlin not configured

When I go to

Answer 1

Closing and restarting Android Studio works for me in that case. Important is that there are no other projects opened in Android Studio before you close it. I suspect that closing Android Studio with multiple opened project windows sometimes messes up the configuration especially after plugin upgrades etc.

Answer 2

The only fix for me was adding

apply plugin: 'kotlin-android-extensions'

in build.gradle (:app)

Answer 3

In my case I had to update Android studio from version 3.4.1. to 3.5 and it resolved the kotlin not configured error.

Answer 4

Simply Create a new Activity and select its language to kotlin Android studio Automatically configured kotlin for you.

Answer 5

Important Update

You should check JDK version before setting config

Kotlin gradle config page has detailed information about this.

Step 1

Check kotlin version in project level gradle file.

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

For kotlin_version '1.2.x' Use jdk NOT jre

Step 2

Check JDK version in File > Project Structure

Or check in build.gradle

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

If no JDK version is set in Project Structure, then choose by Android Studio version

• JDK version is 1.7 for Android Studio Version < 2.2.1
• JDK version is 1.8 for Android Studio Version < 2.2.1

Because Android Studio is bundled with jdk 1.8 since 2.2.1 version.

You have 3 options of kotlin stdlib, choose according JDK version

implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version" //jdk_version == 1.8
implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" //jdk_version == 1.7
implementation"org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version" // jdk_version is < 1.7

if kotlin version is'1.1.x' Use jre NOT jdk

implementation"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version" // or jre8

Update Kotlin Version?

You can update Kotlin version from Tools > Kotlin > Configure Kotlin Updates

Answer 6

The only thing that worked for me was to uninstall the kotlin plugin (File -> Settings -> Plugins -> Kotlin press uninstall) and after a restart of Android Studio reinstall the plugin.