Lifecycle Hooks

Xed-Editor extensions can react to both the extension's own lifecycle and the standard Android activity lifecycle of the host application.

Extension vs Activity Lifecycle

There are two different layers you must understand:

• Extension lifecycle → controlled by Xed-Editor, with each extension having its own lifecycle ( onExtensionLoaded, onUninstalled)
• Android activity lifecycle → forwarded from the host app (Activity callbacks)

Both are available, but they serve different purposes.

Available Lifecycle Methods

All lifecycle methods are defined in your extension's main entry class, which inherits from ExtensionAPI. Ignore the annotations and the context parameter for now. This will be covered on the next page.

@Keep
@Suppress("unused")
class Main(context: ExtensionContext) : ExtensionAPI(context) {
    override fun onExtensionLoaded() {} 
    override fun onUninstalled() {}
    override fun onUpdated() {}

    override fun onActivityCreated(activity: Activity, savedInstanceState: Bundle?) {}
    override fun onActivityResumed(activity: Activity) {}
    override fun onActivityPaused(activity: Activity) {}
    override fun onActivityDestroyed(activity: Activity) {}
}

All lifecycle methods must be overridden in your entry class. The implementations can be empty, but they have to be defined.

Lifecycle Reference Table

Method	Called When	Recommended Use in Extensions
onExtensionLoaded	Extension is loaded into memory	Primary initialization (register commands, load state)
onUninstalled	Extension is removed	Final cleanup (remove cached files)
onUpdated	Extension is updated	Full teardown of all previously registered services before reload
onActivityCreated	Activity is created	React to UI being created (e.g. terminal/editor opened, initialize panels)
onActivityResumed	App enters foreground	Resume active work (refresh UI overlays, continue polling)
onActivityPaused	App goes to background	Pause ongoing work (stop polling, save state, pause animations or updates)
onActivityDestroyed	Activity is destroyed	Cleanup UI-related resources, unregister receivers

IMPORTANT

onUpdated() is invoked before the new extension version is loaded, meaning it runs on the old instance. It must therefore fully clean up all previously registered services (language servers, runners, commands, listeners, etc.) to prevent duplication when the new version is initialized.

onExtensionLoaded() vs onActivityCreated()

onExtensionLoaded() is the primary entry point for extensions and should be used for all initialization such as registering commands, loading state, or starting services. It is guaranteed to run when the extension is loaded, independent of the current UI state.

In contrast, onActivityCreated() is tied to the Android activity lifecycle and may already have been triggered before the extension is loaded. Because of this timing, it is not reliable for initialization and should only be used when reacting to UI creation events that happen after the extension is active (for example when editor or terminal screens are opened).