How to run single Kotlin class from Android Studio

Question

I am new to Kotlin development and I have created a separate Kotlin class in Android Studio as below :

  class MainClass{

    fun main(args: Array<String>)  {
        println("Hello World");
    }
 }

But, How can I run this kotlin class, and where the output will be generated.

Have you tried this https://stackoverflow.com/questions/44823064/run-single-kotlin-class-with-main-function-in-android-studio — Nilesh Panchal, Oct 09 '18 at 05:56
Android studio shows me a kotlin icon to left of main method and when I click on this icon, It shows me below three option: ::::: (NOT IN MY CASE- not showing icon) — Jaimin Modi, Oct 09 '18 at 05:58
this might help https://stackoverflow.com/a/52714573/4936904 — Pavneet_Singh, Oct 09 '18 at 06:30
Where is this practice popular (putting main fun in Android code)? — IgorGanapolsky, Jun 13 '19 at 19:06
@IgorGanapolsky We can test and practice kotlin in android studio. — Jaimin Modi, Jul 11 '19 at 07:28

score 5 · Answer 1 · answered Oct 09 '18 at 06:04

5

your main function has to be a top-level function. Try this:

fun main(args: Array<String>)  {
        println("Hello World");
    }

In order to run it, just click on green the icon next to the function name in AS.

Check out this screenshot

answered Oct 09 '18 at 06:04

Luis Carino

66
4

Top level means where in Activity ? inside onCreate() ? – Jaimin Modi Oct 09 '18 at 06:11
okay got it. But, it giving Exception in thread "main" java.lang.ClassNotFoundException: com.example.jaimin.kotinsetupdemo.MainClassKt at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:264) – Jaimin Modi Oct 09 '18 at 06:13
Create new kotlin file and then paste the above code, after that click the green play icon on the left side of function name.. You will get the output in your Run tab on the bottom left of the screen. – deaddroid Oct 09 '18 at 07:27
1

+1 @JaiminModi Only way I can work around it is by adding this to gradle file: `sourceSets { main { main.kotlin.srcDirs = ['src/main/java'] } }` and oddly, the gradle file needs to be re-synced for every run! – Conti Feb 03 '19 at 20:43

score 0 · Answer 2 · answered Mar 19 '20 at 11:15

0

Use this code, You will see a run icon near function.

class Test {
        companion object {
            @JvmStatic
            fun main(args: Array<String>) {
                println("Hello test!")
            }
        }
    }

answered Mar 19 '20 at 11:15

Yamini

732
7
11

How to run single Kotlin class from Android Studio

2 Answers2