Cannot Cast PsiElement to KtClass Follow

Did you declare dependency on Kotlin plugin in plugin.xml? http://www.jetbrains.org/intellij/sdk/docs/basics/plugin_structure/plugin_dependencies.html#dependency-declaration-in-pluginxml

I did, here's my plugin.xml

<idea-plugin>
    <id>intellijtemplate.djaka.id.intellijtemplate</id>
    <name>Intelij Template</name>
    <vendor email="test@gmail.com" url="http://www.djaka.id">Djaka Pradana</vendor>

    <description>It's just a little short experiment hehehe</description>

    <!--depend on kotlin plugin-->
    <depends>org.jetbrains.kotlin</depends>

    <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/plugin_compatibility.html
         on how to target different products -->
    <!-- uncomment to enable plugin in all products
    <depends>com.intellij.modules.lang</depends>
    -->

    <extensions defaultExtensionNs="com.intellij">
        <!-- Add your extensions here -->
    </extensions>

    <actions>
        <action id="MyAction" class="action.MyAction" text="MyAction"
                description="MyAction">
            <add-to-group group-id="GenerateGroup" anchor="last"/>
        </action>
    </actions>
</idea-plugin>

You are referring to a different Kotlin plugin version than the one bundled with 2019.1.4, this will not work.

Please try replacing in build.gradle

plugins 'Kotlin'

instead of

 plugins 'org.jetbrains.kotlin:1.3.11-release-IJ2018.3-1'

I've replaced it to this one, but unfortunately still getting the same error

intellij {
    version '2019.1.4'
    plugins 'Kotlin'
}

Please provide complete project sources

https://github.com/DjakaTechnology/plugin-experiment Here's the complete sources

I found the following problems:

1) using "import org.jetbrains.kotlin.com.intellij.psi.PsiElement" from Kotlin Plugin instead of "com.intellij.psi.PsiElement" in KtClassHelper

2) in build.gradle, "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.61" was included into project's instead of buildscript classpath

Please fix (1) and change your build.gradle file to the version posted below. Please see http://www.jetbrains.org/intellij/sdk/docs/tutorials/kotlin.html in SDK Docs as reference.

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.61"
    }
}

plugins {
    id 'org.jetbrains.intellij' version '0.4.15'
    id 'org.jetbrains.kotlin.jvm' version '1.3.61'
}

group 'intellijtemplate.djaka.id'
version '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

apply plugin: 'org.jetbrains.intellij'
apply plugin: 'kotlin'

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
}

// See https://github.com/JetBrains/gradle-intellij-plugin/
intellij {
    version '2019.1.4'
    plugins 'Kotlin'
}

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}
patchPluginXml {
    changeNotes """
      Add change notes here.<br>
      <em>most HTML tags may be used</em>"""
}

Thank youu, it works like a charm. I've been stuck in this problem for days.

Hello Mr Yann Cebron I cannot find

import org.jetbrains.kotlin.com.intellij.psi.PsiElement;

This is my build.gradel

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.11"
    }
}
plugins {
    id 'java'
    id 'org.jetbrains.intellij' version '0.4.21'
    id 'org.jetbrains.kotlin.jvm' version '1.3.11'
}

apply plugin: "kotlin"
apply plugin: 'org.jetbrains.intellij'

group 'com.test.plugin'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8
dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    testCompile group: 'junit', name: 'junit', version: '4.12'
}
intellij {
    plugins "Kotlin"
    version '2018.3.6'
    alternativeIdePath 'C:\\Program Files\\Android\\Android Studio'
    updateSinceUntilBuild false
}
patchPluginXml {
    changeNotes """
      Add change notes here.<br>
      <em>most HTML tags may be used</em>"""
}

Nvh Haui,

You have to add a Java dependency in your Gradle:

intellij {
  // ...
  plugins = ['java', 'Kotlin']
}

and in plugin.xml:

<depends>com.intellij.modules.java</depends>

Check the Compatibility with Multiple Products section in our docs for more details.

after I add

plugins = ['java', 'Kotlin'] 

I got error Cannot find builtin plugin java for IDE: C:\Users\hung.nv14\.gradle\caches\modules-2\files-2.1\com.jetbrains.intellij.idea\ideaIC\2018.3.6\be4a083c7dca1159d340fd6dcacc4a78646acfb4\ideaIC-2018.3.6

Should I add plugin in setting -> plugins -> Java ?
I don't know exactly plugin i have to install. Please help me fix it Thank 

Update
in plugin.xml I added

<depends>org.jetbrains.kotlin</depends>
<depends>com.intellij.modules.java</depends>

in build.grable
I added 

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib"
    implementation "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.11"
    testCompile group: 'junit', name: 'junit', version: '4.12'
}

// See https://github.com/JetBrains/gradle-intellij-plugin/
intellij {
    version '2020.2'
    plugins = ['java', 'Kotlin']
    alternativeIdePath 'C:\\Program Files\\Android\\Android Studio'
    updateSinceUntilBuild false
}

my language is Java and i can't import import org.jetbrains.kotlin.com.intellij.psi.PsiElement 

Nvh haui, please follow guide from https://jetbrains.org/intellij/sdk/docs/products/android_studio.html

you should ideally not use "alternativeIdePath" and it cannot be mixed with "version" at the same time anyway.

I think it's not relate my problem. current i can not get kt class from PsiElement. This is my code

public static KtClass getKtClassForElement(@NotNull PsiElement psiElement) {
    System.out.println("getKtClassForElement" + "name : " + psiElement.toString());
    if (psiElement instanceof KtLightElement) {
        System.out.println("psiElement instanceof KtLightElement");
        PsiElement origin = ((KtLightElement) psiElement).getKotlinOrigin();
        if (origin != null) {
            return getKtClassForElement(origin);
        } else {
            return null;
        }

    } else if (psiElement instanceof KtClass && !((KtClass) psiElement).isEnum() &&
            !((KtClass) psiElement).isInterface() &&
            !((KtClass) psiElement).isAnnotation() &&
            !((KtClass) psiElement).isSealed()) {
        System.out.println("psiElement instanceof KtClass ");
        return (KtClass) psiElement;

    } else {
        System.out.println("Else");
        PsiElement parent = psiElement.getParent();
        if (parent == null) {
            return null;
        } else {
            return getKtClassForElement(parent);
        }
    }
}

It's always run in System.out.println("Else") and return null.
Should I using "import org.jetbrains.kotlin.com.intellij.psi.PsiElement" from Kotlin Plugin instead of "com.intellij.psi.PsiElement" in KtClassHelper ?

Please link your full plugin sources, it's impossible to guess from snippets what is happening.

In my company I can not upload source. Do you have any repository and tutorial about KtClass.

I want to create a plugin which can create test for kotlin file. I want to deep search in KtClass but I can not find some tutorial for it.
Could you give me some guide or tutorial ?

Thank you in advance

There is no dedicated tutorial for Kotlin's PSI.

You can find plugins targeting Kotlin in some way with sources available here https://plugins.jetbrains.com/search?search=kotlin&shouldHaveSource=true

Also, make use of https://plugins.jetbrains.com/plugin/227-psiviewer to understand the PSI