Решение Phaethon в Kotlin:
val intent = Intent(this, MyAppWidgetProvider::class.java)
intent.action = AppWidgetManager.ACTION_APPWIDGET_UPDATE
val ids = AppWidgetManager.getInstance(application).getAppWidgetIds(ComponentName(getApplicationContext(),MyAppWidgetProvider::class.java!!))
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, ids)
sendBroadcast(intent)
Где MyAppWidgetProvider получен из AppWidgetProvider: class MyAppWidgetProvider : AppWidgetProvider() {