NOTE: These instructions for upgrading an existing project with Kotlin support is for codebases that are using Gradle 4 (Gradle Plugin version 3.x.x)
To provide support for Kotlin in a project that only has Java support, try the following:
- add the latest Kotlin version number as a static variable in the buildscript section
- add the Kotlin class path to dependencies
Updates to Project gradle file:
buildscript { ext.kotlin_version = "1.2.61" repositories { google() jcenter() } dependencies { classpath 'com.android.tools.build:gradle:3.1.4' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" // NOTE: Do not place your application dependencies here; they belong // in the individual module build.gradle files } }
Updates to Module: app gradle file:
- add two plugins to the top of the file: kotlin-android and kotlin-android-extensions
- add org.jetbrains.kotlin:kotlin-stdlib-jdk7 to the dependencies.
apply plugin: 'com.android.application' apply plugin: 'kotlin-android' apply plugin: 'kotlin-android-extensions'
dependencies { implementation fileTree(dir: 'libs', include: ['*.jar']) // Kotlin support implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" }
Once these updates are made in Android Studio, try building/running the code and make sure everything looks ok.
From here take a look at the shortcuts below to convert existing Java files to Kotlin code.
How to convert your Java file to Kotlin:
use Shift-Alt-Cmd-K or Shift-Shift + search Convert Java File to Kotlin File.