How to use code completion in comments

Please always provide the full context and code.

Hi, I want to type "," or "@" when writing a comment to prompt some code completion. Is there any way to do this? It would be nice to have a simple example. 

I use the following code to trigger code completion. But it has no effect in the comments

import com.intellij.codeInsight.AutoPopupController
import com.intellij.codeInsight.editorActions.TypedHandlerDelegate
import com.intellij.openapi.editor.Editor
import com.intellij.openapi.project.Project
import com.intellij.psi.PsiFile

class MyTypedHandler : TypedHandlerDelegate() {
    override fun charTyped(c: Char, project: Project, editor: Editor, file: PsiFile): Result {
        if (c == ',' || c == '@') {
            println("MyTypedHandler")
            AutoPopupController.getInstance(project).scheduleAutoPopup(editor)
            return Result.STOP
        }
        return Result.CONTINUE  
    }
}

import com.intellij.codeInsight.completion.CompletionContributor
import com.intellij.codeInsight.completion.CompletionParameters
import com.intellij.codeInsight.completion.CompletionResultSet
import com.intellij.codeInsight.lookup.LookupElementBuilder


class MyCompletionContributor : CompletionContributor() {

    override fun fillCompletionVariants(parameters: CompletionParameters, result: CompletionResultSet) {
        result.addElement(LookupElementBuilder.create("Hello"))
        result.addElement(LookupElementBuilder.create("World"))
        result.addLookupAdvertisement("This is an advertisement")
    }



}

Why do you override fillCompletionVariants() instead of implementing providers and registering them with CompletionContributor.extend()?

https://plugins.jetbrains.com/docs/intellij/completion-contributor.html

When I try the following code. It still didn't work.

The effect is the same as the previous picture.

import com.intellij.codeInsight.completion.*
import com.intellij.codeInsight.lookup.LookupElementBuilder
import com.intellij.patterns.PlatformPatterns
import com.intellij.util.ProcessingContext


class MyCompletionContributor : CompletionContributor() {
//
//    override fun fillCompletionVariants(parameters: CompletionParameters, result: CompletionResultSet) {
//        result.addElement(LookupElementBuilder.create("Hello"))
//        result.addElement(LookupElementBuilder.create("World"))
//        result.addLookupAdvertisement("This is an advertisement")
//    }

    init {
        extend(
            CompletionType.BASIC, PlatformPatterns.psiElement(),
            object :
                CompletionProvider<CompletionParameters>() {
                override fun addCompletions(parameters: CompletionParameters, context: ProcessingContext,
                                            resultSet: CompletionResultSet) {
                    resultSet.addElement(LookupElementBuilder.create("Hello"))
                    resultSet.addElement(LookupElementBuilder.create("World"))
                }
            }
        )
    }
}

If I remember correctly, I tried "CompletionContributor.extend()" I just tried again.

It seems that JavaDocCompletionContributor stops completion in some cases, see stopHere occurrences in https://github.com/JetBrains/intellij-community/blob/master/java/java-impl/src/com/intellij/codeInsight/completion/JavaDocCompletionContributor.java.

To fix it, add order="first" for your contributor in your plugin.xml (and always provide the full context, including registration in plugin.xml).

After I modified the plugin.xml file. The effect is the same as before. 

<completion.contributor
        language="JAVA"
        id="param" order="first"
        implementationClass="com.aiwan.jorm.annotation.MyCompletionContributor"/>

I don't know what can be the problem. It works for me perfectly.

Registration:

<extensions defaultExtensionNs="com.intellij">
    <completion.contributor
            language="JAVA" order="first"
            implementationClass="com.example.myplugin.MyCompletionContributor"/>
</extensions>

Implementation:

package com.example.myplugin
import com.intellij.codeInsight.completion.*
import com.intellij.codeInsight.lookup.LookupElementBuilder
import com.intellij.patterns.PlatformPatterns
import com.intellij.patterns.PlatformPatterns.psiElement
import com.intellij.util.ProcessingContext


class MyCompletionContributor : CompletionContributor() {

    init {
        extend(
            CompletionType.BASIC, psiElement(),
            object : CompletionProvider<CompletionParameters>() {
                override fun addCompletions(parameters: CompletionParameters, context: ProcessingContext,
                                            resultSet: CompletionResultSet) {
                    resultSet.addElement(LookupElementBuilder.create("Hello"))
                    resultSet.addElement(LookupElementBuilder.create("World"))
                }
            }
        )
    }
}

Screenshot:

Ok. Thank you.

Hi Guys, I am having same Issue, Code Completion triggers out side comment but when I try totrigger it in comments, It does not work. 

class MyCompletionContributor extends CompletionContributor {

class MyCompletionContributor extends CompletionContributor {


    public MyCompletionContributor() {
        extend(CompletionType.BASIC,
                PlatformPatterns.psiElement().inside(PsiComment.class),
                new CompletionProvider<CompletionParameters>() {
                    @Override
                    public void addCompletions(@NotNull CompletionParameters parameters,
                                               @NotNull ProcessingContext context,
                                               @NotNull CompletionResultSet resultSet) {
                        resultSet.addElement(LookupElementBuilder.create("Hello"));
                        resultSet.addElement(LookupElementBuilder.create("World"));
                        resultSet.addElement(LookupElementBuilder.create("UniversalCompletionItem"));
                    }
                }
        );
    }

}

<completion.contributor
        language="JAVA" order="first"
        implementationClass="org.intellij.sdk.language.MyCompletionContributor"/>

I also tried replacing PlatformPatterns.psiElement().inside(PsiComment.class) with  psiElement()  with no luck.

However when I use PlatformPatterns.psiElement(PsiElement.class).withElementType(JavaTokenType.IDENTIFIER)

It doe trigger code completion but not inside the comment section.

Yasirfarhan 

Hi. I used another way to solve the problem.

import com.intellij.codeInsight.editorActions.TypedHandlerDelegate
import com.intellij.openapi.command.WriteCommandAction
import com.intellij.openapi.editor.Editor
import com.intellij.openapi.project.Project
import com.intellij.openapi.ui.popup.ListPopup
import com.intellij.openapi.ui.popup.PopupStep
import com.intellij.openapi.ui.popup.util.BaseListPopupStep
import com.intellij.psi.PsiComment
import com.intellij.psi.PsiFile
import com.intellij.psi.util.PsiTreeUtil
import com.intellij.ui.popup.list.ListPopupImpl
import org.jetbrains.kotlin.idea.KotlinLanguage

class MyTypedHandlerDelegate : TypedHandlerDelegate() {
    private val key = ','
    override fun charTyped(c: Char, project: Project, editor: Editor, file: PsiFile): Result {
        if (c == key) {
            showPopup(project, editor, file)
            return Result.CONTINUE
        }
        return Result.CONTINUE
    }

    private fun showPopup(project: Project, editor: Editor, file: PsiFile) {
        if (file.language !is KotlinLanguage) {
            return
        }
        var element = file.findElementAt(editor.caretModel.offset)
        if (element != null) {
            element = PsiTreeUtil.findFirstParent(element) { it is PsiComment }
        }
        if (element is PsiComment) {
           createPopup(project, listOf("test1", "test2", "test3")) {
               WriteCommandAction.runWriteCommandAction(project) {
               editor.document.deleteString(editor.caretModel.offset - key.toString().length, editor.caretModel.offset)
               editor.document.insertString(editor.caretModel.offset, it)
               editor.caretModel.moveToOffset(editor.caretModel.offset + it.length)
           } }.showInBestPositionFor(editor)
        }
    }
    private fun createPopup(project: Project, actions: List<String>, invokeAction: (String) -> Unit): ListPopup {
        val step = object : BaseListPopupStep<String>(null, actions) {
            override fun getTextFor(action: String) = action
            override fun onChosen(selectedValue: String, finalChoice: Boolean): PopupStep<*>? {
                invokeAction(selectedValue)
                return FINAL_CHOICE
            }
        }
        return ListPopupImpl(project, step)
    }
}

plugin.xml

<typedHandler implementation="org.your.path.MyTypedHandlerDelegate"/>

Result:  A prompt appears when I type ",".  I hope that will be helpful.

Thanks for the input.

Here are my observations about TypedHandlerDelegate. It is much more complex for my use case, I am trying to avoid manually handling triggers. It also triggered more frequently then the other one which can cause performance issue.

Hi,

Using type handler approach is an overkill, and it shouldn't be implemented this way. Please share your plugin source code or a minimal reproducible example plugin, so I can investigate the issue.

Hi,I have the same problem, I want to customize some suggestions while writing comments

 plugin.xml:

<completion.contributor
        language="JAVA" order="first"
        implementationClass="com.test.MyCompletionContributor"/>

MyCompletionContributor.java:

public MyCompletionContributor() {
    extend(CompletionType.BASIC,
        PlatformPatterns.psiElement().inside(PsiComment.class),
        new CompletionProvider<CompletionParameters>() {
            @Override
            public void addCompletions(@NotNull CompletionParameters parameters,
                @NotNull ProcessingContext context,

                @NotNull CompletionResultSet resultSet) {
 resultSet.addElement(LookupElementBuilder.create("Hello"));
 resultSet.addElement(LookupElementBuilder.create("World"));
                    }
                }
        );
    }

but it does not work while in  single line comment

it only works in comments block  while typing  @