Android Studio 舊 Java 專案加入 kotlin support

1. Check android studio version

2. Check Preferences plugins Kotlin installed

3. Go to https://kotlinlang.org/docs/releases.html, check release details

4. Open Android Studio Project

5. Update build.gradle(project:專案名稱)

6. Add

ext.kotlin_version = '1.4.31' (此處數字為 Release details 版本)

classpath "org.jetbrains.kotlin:kotlin-gradle-plugon:$kotlin_version" ($為前一行定義的版號)

7. Update build.gradle(module)

8. dependencies add

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"

9. Add plugin

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

10. Sync Now 

11. Wait download ...

Done