Kotlin/Native 入门——在 IntelliJ IDEA 中

This tutorial demonstrates how to use IntelliJ IDEA for creating a Kotlin/Native application.

To get started, install the latest version of IntelliJ IDEA. The tutorial is applicable to both IntelliJ IDEA Community Edition and the Ultimate Edition.

Before you start

1. Download and install the latest version of IntelliJ IDEA with the latest Kotlin plugin.
2. Clone the project template by selecting File | New | Project from Version Control in IntelliJ IDEA.

3. Open the build.gradle.kts file, the build script that contains the project settings. To create Kotlin/Native applications, you need the Kotlin Multiplatform Gradle plugin installed. Ensure that you use the latest version of the plugin:

   plugins {
       kotlin("multiplatform") version "1.9.24"
   }
   

4. Follow the suggestion to reload Gradle files:

   

• Read more about these settings in the Multiplatform Gradle DSL reference.
• Read more about the Gradle build system in the documentation.

Build and run the application

Open the Main.kt file in the src/nativeMain/kotlin/ directory, then press the green icon in the gutter to run the code:

IntelliJ IDEA runs the code using the Gradle task. You will see the result in the Run tab:

After the first run, you will see the corresponding run configuration on the top bar in the IDE:

IntelliJ IDEA Ultimate users can install the Native Debugging Support plugin that allows to debug compiled native executables, and also automatically creates run configurations for imported Kotlin/Native projects.

You can configure IntelliJ IDEA to build your project automatically:

1. Go to Settings/Preferences | Build, Execution, Deployment | Compiler.
2. On the Compiler page, select Build project automatically.
3. Apply the changes.

Now when you make changes in the class files or save the file (Ctrl + S/Cmd + S), IntelliJ IDEA automatically performs an incremental build of the project.

Update the application

Count the letters in your name

1. Open the file Main.kt in src/nativeMain/kotlin.

   The src directory contains Kotlin source files. The Main.kt file includes code that prints "Hello, Kotlin/Native!" using the println() function.

2. Add code to read the input. Use the readln() function to read the input value and assign it to the name variable:

   fun main() {
       // Read the input value.
       println("Hello, enter your name:")
       val name = readln()
   }
   

3. To run this app using Gradle, specify System.in as the input to use in the build.gradle.kts file and load the Gradle changes:

   kotlin {
       //...
       nativeTarget.apply {
           binaries {
               executable {
                   entryPoint = "main"
                   runTask?.standardInput = System.`in`
               }
           }
       }
       //...
   }
   

   {initial-collapse-state="collapsed" collapsed-title="runTask?.standardInput = System.in"}

4. Eliminate the whitespaces and count the letters:

   • Use the replace() function to remove the empty spaces in the name.
   • Use the scope function let to run the function within the object context.
   • Use a string template to insert your name length into the string by adding a dollar sign $ and enclosing it in curly braces – ${it.length}. it is the default name of a lambda parameter.

   fun main() {
       // Read the input value.
       println("Hello, enter your name:")
       val name = readln()
       // Count the letters in the name.
       name.replace(" ", "").let {
           println("Your name contains ${it.length} letters")
       }
   }
   

5. Run the application.

6. Enter your name and enjoy the result:

   

Count the unique letters in your name

1. Open the file Main.kt in src/nativeMain/kotlin.

2. Declare the new extension function countDistinctCharacters() for String:

   • Convert the name to lowercase using the lowercase() function.
   • Convert the input string to a list of characters using the toList() function.
   • Select only the distinct characters in your name using the distinct() function.
   • Count the distinct characters using the count() function.

   fun String.countDistinctCharacters() = lowercase().toList().distinct().count()
   

3. Use the countDistinctCharacters() function to count the unique letters in your name:

   fun String.countDistinctCharacters() = lowercase().toList().distinct().count()
   
   fun main() {
       // Read the input value.
       println("Hello, enter your name:")
       val name = readln()
       // Count the letters in the name.
       name.replace(" ", "").let {
           println("Your name contains ${it.length} letters")
           // Print the number of unique letters.
           println("Your name contains ${it.countDistinctCharacters()} unique letters")
       }
   }
   

4. Run the application.

5. Enter your name and enjoy the result:

   

下一步做什么？

Once you have created your first application, you can complete our long-form tutorial on Kotlin/Native, Create an app using C Interop and libcurl that explains how to create a native HTTP client and interoperate with C libraries.