Dart VM Extension Development

Applies to FlutterX versions that expose the dartVmDevTool extension point

FlutterX exposes Dart VM ToolWindow tabs through the shop.itbug.FlutterCheckVersionX.dartVmDevTool extension point. The built-in Vm, Memory, Http Monitor, Logging, Provider, Shared Preferences, Hive CE, and Drift DB tabs are registered through the same extension point that third-party plugins can use.

Registration

A third-party plugin must depend on FlutterX and register dartVmDevTool under the FlutterX namespace.

<depends>shop.itbug.FlutterCheckVersionX</depends>

<extensions defaultExtensionNs="shop.itbug.FlutterCheckVersionX">
    <dartVmDevTool
        id="myTool"
        implementation="com.example.MyDartVmDevTool"
        descriptionKey="my.tool.description"
        order="after hive"/>
</extensions>

Attributes

Attribute	Required	Description
id	Yes	Stable tab ID. FlutterX stores hidden tab settings by this value, so avoid changing it after publishing.
implementation	Yes	Class that implements shop.itbug.flutterx.api.vm.DartVmDevToolExtension.
descriptionKey	No	I18n key resolved from the contributing plugin resource bundle and shown in the Dart VM settings page.
order	No	IntelliJ extension ordering, for example first, last, after hive, or before drift.

If descriptionKey is omitted or cannot be resolved, FlutterX simply does not show a description.

Implementing a Tool

Keep extension classes stateless and avoid heavy work in constructors. Put UI setup and Dart VM Service access into the component lifecycle created by createComponent.

package com.example

import com.intellij.openapi.project.Project
import shop.itbug.flutterx.api.vm.DartVmDevToolContext
import shop.itbug.flutterx.api.vm.DartVmDevToolExtension
import java.awt.BorderLayout
import javax.swing.JComponent
import javax.swing.JLabel
import javax.swing.JPanel

class MyDartVmDevTool : DartVmDevToolExtension {
    override fun getTabTitle(project: Project): String = "My Tool"

    override fun isAvailable(context: DartVmDevToolContext): Boolean {
        return true
    }

    override fun createComponent(context: DartVmDevToolContext): JComponent {
        return JPanel(BorderLayout()).apply {
            add(JLabel("My FlutterX Dart VM tool"), BorderLayout.CENTER)
        }
    }
}

createComponent returns a Swing JComponent. FlutterX does not expose Compose or Jewel types as public API, which keeps third-party plugins less sensitive to Kotlin, Compose, and Jewel version changes.

Reading Running Flutter Apps

DartVmDevToolContext exposes the current project, the ToolWindow, and the live list of running Flutter apps.

interface DartVmDevToolContext {
    val project: Project
    val toolWindow: ToolWindow
    val runningApps: StateFlow<List<DartVmApp>>
}

runningApps is live state. If the user opens the FlutterX Dart VM ToolWindow before starting a Flutter app, your component should subscribe to context.runningApps to receive updates.

interface DartVmApp {
    val appId: String
    val vmUrl: String
    val deviceId: String
    val mode: String
    val vmService: VmService
}

Use DartVmApp.vmService to call Dart VM Service RPCs. These calls may be slow or fail, so do not block the EDT.

Localized Description

To show a description in the Dart VM settings page, set descriptionKey and provide the text in your plugin resource bundle.

<idea-plugin>
    <resource-bundle>messages.MyPluginBundle</resource-bundle>

    <depends>shop.itbug.FlutterCheckVersionX</depends>

    <extensions defaultExtensionNs="shop.itbug.FlutterCheckVersionX">
        <dartVmDevTool
            id="myTool"
            implementation="com.example.MyDartVmDevTool"
            descriptionKey="my.tool.description"
            order="after hive"/>
    </extensions>
</idea-plugin>

my.tool.description=Shows custom diagnostics collected from Dart VM Service.

Showing and Hiding Tabs

FlutterX automatically lists all registered Dart VM tabs in the Dart VM settings page, including third-party tabs. Tabs are shown by default. When the user clears the checkbox, the tab is hidden.

Hidden state is stored by extension id. Do not change a published id unless you accept resetting user visibility preferences.

Notes

• v1 does not refresh already-open Dart VM tabs immediately when a third-party plugin is installed or uninstalled. Reopen the ToolWindow or restart the IDE.
• If one extension fails while creating its component, FlutterX skips that tab and continues loading the others.
• Use isAvailable when a tab should only appear for certain projects, dependencies, or runtime states.
• Components should release their own listeners, coroutines, and VM Service subscriptions.

Validation

Recommended checks for third-party extensions:

• ./gradlew compileKotlin passes.
• ./gradlew verifyPluginStructure passes.
• The third-party tab appears in FlutterX Dart VM.
• Ordering such as order="after hive" works.
• If the ToolWindow is opened before the Flutter app starts, UI subscribed to runningApps updates correctly.
• Hiding the tab in Dart VM settings removes it, and showing it again restores it.