Implementation of Card Analysis Widget to display deck statistics for a particular deck.

This commit introduces the Card Analysis Extra Widget, which displays a deck with the number of cards that are new, in learning, due for review and deck name.
Features:
- Displays deck names and statistics (new, learning, and review counts).
- Updates every minute using a recurring alarm.

AnkiDroid/src/main/AndroidManifest.xml

@@ -538,6 +538,33 @@
             </intent-filter>
         </activity>
 
+        <!-- A widget that displays a deck name and number of cards to review on the Android home screen.
+             The way to add it depends on the phone. It usually consists in a long press on the screen, followed by finding a "widget" button"-->
+        <receiver
+            android:name="com.ichi2.widget.cardanalysis.CardAnalysisWidget"
+            android:label="@string/card_analysis_extra_widget_description"
+            android:exported="false"
+            >
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/widget_provider_card_analysis" />
+        </receiver>
+
+        <!-- Configuration view for the CardAnalysisWidget above.
+             It is opened when adding a new widget and
+             by configuration button which appears when the widget is hold or resized.-->
+        <activity
+            android:name="com.ichi2.widget.cardanalysis.CardAnalysisWidgetConfig"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
+            </intent-filter>
+        </activity>
+
         <receiver android:name="com.ichi2.widget.WidgetPermissionReceiver"
             android:exported="true">
             <intent-filter>

AnkiDroid/src/main/java/com/ichi2/anki/AnkiDroidApp.kt

@@ -60,6 +60,7 @@ import com.ichi2.utils.ExceptionUtil
 import com.ichi2.utils.KotlinCleanup
 import com.ichi2.utils.LanguageUtil
 import com.ichi2.utils.Permissions
+import com.ichi2.widget.cardanalysis.CardAnalysisWidget
 import com.ichi2.widget.deckpicker.DeckPickerWidget
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -298,6 +299,7 @@ open class AnkiDroidApp : Application(), Configuration.Provider, ChangeManager.S
         Timber.d("ChangeSubscriber - opExecuted called with changes: $changes")
         if (changes.studyQueues) {
             DeckPickerWidget.updateDeckPickerWidgets(this)
+            CardAnalysisWidget.updateCardAnalysisWidgets(this)
         } else {
             Timber.d("No relevant changes to update the widget")
         }

AnkiDroid/src/main/java/com/ichi2/anki/DeckUtils.kt

@@ -0,0 +1,55 @@
+/*
+ *  Copyright (c) 2024 Anoop <xenonnn4w@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.ichi2.anki
+
+import com.ichi2.anki.CollectionManager.withCol
+import com.ichi2.libanki.Decks
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+object DeckUtils {
+
+    /**
+     * Checks if a given deck, including its subdecks if specified, is empty.
+     *
+     * @param decks The [Decks] instance containing the decks to check.
+     * @param deckId The ID of the deck to check.
+     * @param includeSubdecks If true, includes subdecks in the check. Default is true.
+     * @return `true` if the deck (and subdecks if specified) is empty, otherwise `false`.
+     */
+    private fun isDeckEmpty(decks: Decks, deckId: Long, includeSubdecks: Boolean = true): Boolean {
+        val deckIds = decks.deckAndChildIds(deckId)
+        val totalCardCount = decks.cardCount(*deckIds.toLongArray(), includeSubdecks = includeSubdecks)
+        return totalCardCount == 0
+    }
+
+    /**
+     * Checks if the default deck is empty.
+     *
+     * This method runs on an IO thread and accesses the collection to determine if the default deck (with ID 1) is empty.
+     *
+     * @return `true` if the default deck is empty, otherwise `false`.
+     */
+    suspend fun isDefaultDeckEmpty(): Boolean {
+        val defaultDeckId = 1L
+        return withContext(Dispatchers.IO) {
+            withCol {
+                isDeckEmpty(decks, defaultDeckId)
+            }
+        }
+    }
+}

AnkiDroid/src/main/java/com/ichi2/widget/cardanalysis/CardAnalysisWidget.kt

@@ -0,0 +1,236 @@
+/*
+ *  Copyright (c) 2024 Anoop <xenonnn4w@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.ichi2.widget.cardanalysis
+
+import android.app.PendingIntent
+import android.appwidget.AppWidgetManager
+import android.appwidget.AppWidgetManager.ACTION_APPWIDGET_UPDATE
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.widget.RemoteViews
+import com.ichi2.anki.AnkiDroidApp
+import com.ichi2.anki.CrashReportService
+import com.ichi2.anki.R
+import com.ichi2.anki.Reviewer
+import com.ichi2.anki.analytics.UsageAnalytics
+import com.ichi2.anki.pages.DeckOptions
+import com.ichi2.widget.ACTION_UPDATE_WIDGET
+import com.ichi2.widget.AnalyticsWidgetProvider
+import com.ichi2.widget.cancelRecurringAlarm
+import com.ichi2.widget.deckpicker.getDeckNameAndStats
+import com.ichi2.widget.setRecurringAlarm
+import kotlinx.coroutines.launch
+import timber.log.Timber
+
+/**
+ * This widget displays a deck with the respective new, learning, and review card counts.
+ * It updates every minute and if there is any changes in study queues.
+ * It allows user to open the reviewer directly by clicking on the deck same as deckpicker.
+ * It can be configured and reconfigured by holding the widget.
+ */
+class CardAnalysisWidget : AnalyticsWidgetProvider() {
+
+    companion object {
+
+        /**
+         * Key used for passing the selected deck ID in the intent extras.
+         */
+        const val EXTRA_SELECTED_DECK_ID = "card_analysis_widget_selected_deck_id"
+
+        /**
+         * Updates the widget with the deck data.
+         *
+         * This method updates the widget view content with the deck data corresponding
+         * to the provided deck ID. If the deck is deleted, the widget will be cleared.
+         *
+         * @param context the context of the application
+         * @param appWidgetManager the AppWidgetManager instance
+         * @param appWidgetId the ID of the app widget
+         * @param deckId the ID of the deck to be displayed in the widget.
+         */
+        fun updateWidget(
+            context: Context,
+            appWidgetManager: AppWidgetManager,
+            appWidgetId: Int,
+            deckId: LongArray
+        ) {
+            val remoteViews = RemoteViews(context.packageName, R.layout.widget_card_analysis)
+
+            AnkiDroidApp.applicationScope.launch {
+                val deckData = getDeckNameAndStats(deckId.toList())
+
+                if (deckData.isEmpty()) {
+                    appWidgetManager.updateAppWidget(appWidgetId, remoteViews)
+                    return@launch
+                }
+
+                val deck = deckData[0]
+                remoteViews.setTextViewText(R.id.deckNameCardAnalysis, deck.name)
+                remoteViews.setTextViewText(R.id.deckNew_card_analysis_widget, deck.newCount.toString())
+                remoteViews.setTextViewText(R.id.deckDue_card_analysis_widget, deck.reviewCount.toString())
+                remoteViews.setTextViewText(R.id.deckLearn_card_analysis_widget, deck.learnCount.toString())
+
+                val isEmptyDeck = deck.newCount == 0 && deck.reviewCount == 0 && deck.learnCount == 0
+
+                val intent = if (!isEmptyDeck) {
+                    Intent(context, Reviewer::class.java).apply {
+                        action = Intent.ACTION_VIEW
+                        putExtra("deckId", deck.deckId)
+                    }
+                } else {
+                    DeckOptions.getIntent(context, deck.deckId)
+                }
+                val pendingIntent = PendingIntent.getActivity(
+                    context,
+                    deck.deckId.toInt(),
+                    intent,
+                    PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
+                )
+                remoteViews.setOnClickPendingIntent(R.id.deckNameCardAnalysis, pendingIntent)
+
+                appWidgetManager.updateAppWidget(appWidgetId, remoteViews)
+            }
+        }
+
+        /**
+         * Updates the Card Analysis Widgets based on the current state of the application.
+         * It fetches the App Widget IDs and updates each widget with the associated deck ID.
+         */
+        fun updateCardAnalysisWidgets(context: Context) {
+            val appWidgetManager = AppWidgetManager.getInstance(context)
+
+            val provider = ComponentName(context, CardAnalysisWidget::class.java)
+            Timber.d("Fetching appWidgetIds for provider: $provider")
+
+            val appWidgetIds = appWidgetManager.getAppWidgetIds(provider)
+            Timber.d("AppWidgetIds to update: ${appWidgetIds.joinToString(", ")}")
+
+            for (appWidgetId in appWidgetIds) {
+                val widgetPreferences = CardAnalysisWidgetPreferences(context)
+                val deckId = widgetPreferences.getSelectedDeckIdFromPreferences(appWidgetId)
+                updateWidget(context, appWidgetManager, appWidgetId, deckId)
+            }
+        }
+    }
+
+    override fun performUpdate(
+        context: Context,
+        appWidgetManager: AppWidgetManager,
+        appWidgetIds: IntArray,
+        usageAnalytics: UsageAnalytics
+    ) {
+        Timber.d("Performing widget update for appWidgetIds: %s", appWidgetIds)
+
+        val widgetPreferences = CardAnalysisWidgetPreferences(context)
+
+        for (widgetId in appWidgetIds) {
+            Timber.d("Updating widget with ID: $widgetId")
+            val selectedDeckId = widgetPreferences.getSelectedDeckIdFromPreferences(widgetId)
+
+            /**Explanation of behavior when selectedDeckId is empty
+             * If selectedDeckId is empty, the widget will retain the previous deck.
+             * This behavior ensures that the widget does not display an empty view, which could be
+             * confusing to the user. Instead, it maintains the last known state until a new valid
+             * deck ID is provided. This approach prioritizes providing a consistent
+             * user experience over showing an empty or default state.
+             */
+            Timber.d("Selected deck ID: $selectedDeckId for widget ID: $widgetId")
+            updateWidget(context, appWidgetManager, widgetId, selectedDeckId)
+            setRecurringAlarm(context, widgetId, CardAnalysisWidget::class.java)
+        }
+
+        Timber.d("Widget update process completed for appWidgetIds: ${appWidgetIds.joinToString(", ")}")
+    }
+
+    override fun onReceive(context: Context?, intent: Intent?) {
+        if (context == null || intent == null) {
+            Timber.e("Context or intent is null in onReceive")
+            return
+        }
+        super.onReceive(context, intent)
+
+        val widgetPreferences = CardAnalysisWidgetPreferences(context)
+
+        when (intent.action) {
+            ACTION_APPWIDGET_UPDATE -> {
+                val appWidgetManager = AppWidgetManager.getInstance(context)
+
+                // Retrieve the widget ID from the intent
+                val appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID)
+                val selectedDeckId = intent.getLongExtra(EXTRA_SELECTED_DECK_ID, -1L)
+
+                Timber.d("Received ACTION_APPWIDGET_UPDATE with widget ID: $appWidgetId and selectedDeckId: $selectedDeckId")
+
+                if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID && selectedDeckId != -1L) {
+                    Timber.d("Updating widget with ID: $appWidgetId")
+                    // Wrap selectedDeckId into a LongArray
+                    updateWidget(context, appWidgetManager, appWidgetId, longArrayOf(selectedDeckId))
+                    Timber.d("Widget update process completed for widget ID: $appWidgetId")
+                }
+            }
+            // This custom action is received to update a specific widget.
+            // It is triggered by the setRecurringAlarm method to refresh the widget's data periodically.
+            ACTION_UPDATE_WIDGET -> {
+                val appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID)
+                if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
+                    Timber.d("Received ACTION_UPDATE_WIDGET for widget ID: $appWidgetId")
+                }
+            }
+            AppWidgetManager.ACTION_APPWIDGET_DELETED -> {
+                Timber.d("ACTION_APPWIDGET_DELETED received")
+                val appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID)
+                if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
+                    Timber.d("Deleting widget with ID: $appWidgetId")
+                    cancelRecurringAlarm(context, appWidgetId, CardAnalysisWidget::class.java)
+                    widgetPreferences.deleteDeckData(appWidgetId)
+                } else {
+                    Timber.e("Invalid widget ID received in ACTION_APPWIDGET_DELETED")
+                }
+            }
+            AppWidgetManager.ACTION_APPWIDGET_ENABLED -> {
+                Timber.d("Widget enabled")
+            }
+            AppWidgetManager.ACTION_APPWIDGET_DISABLED -> {
+                Timber.d("Widget disabled")
+            }
+            else -> {
+                Timber.e("Unexpected action received: ${intent.action}")
+                CrashReportService.sendExceptionReport(
+                    Exception("Unexpected action received: ${intent.action}"),
+                    "CardAnalysisWidget - onReceive",
+                    null,
+                    onlyIfSilent = true
+                )
+            }
+        }
+    }
+
+    override fun onDeleted(context: Context?, appWidgetIds: IntArray?) {
+        if (context == null) {
+            Timber.w("Context is null in onDeleted")
+            return
+        }
+
+        val widgetPreferences = CardAnalysisWidgetPreferences(context)
+
+        appWidgetIds?.forEach { widgetId ->
+            cancelRecurringAlarm(context, widgetId, CardAnalysisWidget::class.java)
+            widgetPreferences.deleteDeckData(widgetId)
+        }
+    }
+}

AnkiDroid/src/main/java/com/ichi2/widget/cardanalysis/CardAnalysisWidgetConfig.kt

@@ -0,0 +1,370 @@
+/*
+ *  Copyright (c) 2024 Anoop <xenonnn4w@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.ichi2.widget.cardanalysis
+
+import android.appwidget.AppWidgetManager
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.ContextWrapper
+import android.content.Intent
+import android.content.IntentFilter
+import android.os.Bundle
+import android.view.View
+import android.widget.Button
+import androidx.activity.OnBackPressedCallback
+import androidx.core.view.isVisible
+import androidx.lifecycle.lifecycleScope
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.google.android.material.floatingactionbutton.FloatingActionButton
+import com.google.android.material.snackbar.Snackbar
+import com.ichi2.anki.AnkiActivity
+import com.ichi2.anki.CollectionManager.withCol
+import com.ichi2.anki.DeckUtils
+import com.ichi2.anki.R
+import com.ichi2.anki.dialogs.DeckSelectionDialog
+import com.ichi2.anki.dialogs.DeckSelectionDialog.DeckSelectionListener
+import com.ichi2.anki.dialogs.DeckSelectionDialog.SelectableDeck
+import com.ichi2.anki.dialogs.DiscardChangesDialog
+import com.ichi2.anki.showThemedToast
+import com.ichi2.anki.snackbar.BaseSnackbarBuilderProvider
+import com.ichi2.anki.snackbar.SnackbarBuilder
+import com.ichi2.anki.snackbar.showSnackbar
+import com.ichi2.widget.WidgetConfigScreenAdapter
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import timber.log.Timber
+
+class CardAnalysisWidgetConfig : AnkiActivity(), DeckSelectionListener, BaseSnackbarBuilderProvider {
+
+    private var appWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID
+    lateinit var deckAdapter: WidgetConfigScreenAdapter
+    private lateinit var cardAnalysisWidgetPreferences: CardAnalysisWidgetPreferences
+
+    /**
+     * Maximum number of decks allowed in the widget.
+     */
+    private val MAX_DECKS_ALLOWED = 1
+    private var hasUnsavedChanges = false
+    private var isAdapterObserverRegistered = false
+    private lateinit var onBackPressedCallback: OnBackPressedCallback
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        if (showedActivityFailedScreen(savedInstanceState)) {
+            return
+        }
+
+        super.onCreate(savedInstanceState)
+
+        if (!ensureStoragePermissions()) {
+            return
+        }
+
+        setContentView(R.layout.widget_deck_picker_config)
+
+        cardAnalysisWidgetPreferences = CardAnalysisWidgetPreferences(this)
+
+        appWidgetId = intent.extras?.getInt(
+            AppWidgetManager.EXTRA_APPWIDGET_ID,
+            AppWidgetManager.INVALID_APPWIDGET_ID
+        ) ?: AppWidgetManager.INVALID_APPWIDGET_ID
+
+        if (appWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
+            Timber.v("Invalid App Widget ID")
+            finish()
+            return
+        }
+
+        // Check if the collection is empty before proceeding and if the collection is empty, show a toast instead of the configuration view.
+        lifecycleScope.launch {
+            if (isCollectionEmpty()) {
+                showThemedToast(
+                    this@CardAnalysisWidgetConfig,
+                    R.string.app_not_initialized_new,
+                    false
+                )
+                finish()
+                return@launch
+            }
+
+            initializeUIComponents()
+        }
+    }
+
+    fun showSnackbar(message: CharSequence) {
+        showSnackbar(
+            message,
+            Snackbar.LENGTH_LONG
+        )
+    }
+
+    fun showSnackbar(messageResId: Int) {
+        showSnackbar(getString(messageResId))
+    }
+
+    fun initializeUIComponents() {
+        deckAdapter = WidgetConfigScreenAdapter { deck, position ->
+            deckAdapter.removeDeck(deck.deckId)
+            showSnackbar(R.string.deck_removed_from_widget)
+            updateViewVisibility()
+            updateFabVisibility()
+            updateDoneButtonVisibility()
+            hasUnsavedChanges = true
+            setUnsavedChanges(true)
+        }
+
+        findViewById<RecyclerView>(R.id.recyclerViewSelectedDecks).apply {
+            layoutManager = LinearLayoutManager(context)
+            adapter = this@CardAnalysisWidgetConfig.deckAdapter
+        }
+
+        setupDoneButton()
+
+        findViewById<FloatingActionButton>(R.id.fabWidgetDeckPicker).setOnClickListener {
+            showDeckSelectionDialog()
+        }
+
+        updateViewWithSavedPreferences()
+
+        // Update the visibility of the "no decks" placeholder and the widget configuration container
+        updateViewVisibility()
+
+        registerReceiver(widgetRemovedReceiver, IntentFilter(AppWidgetManager.ACTION_APPWIDGET_DELETED))
+
+        onBackPressedCallback = object : OnBackPressedCallback(false) {
+            override fun handleOnBackPressed() {
+                if (hasUnsavedChanges) {
+                    showDiscardChangesDialog()
+                }
+            }
+        }
+
+        onBackPressedDispatcher.addCallback(this, onBackPressedCallback)
+
+        // Register the AdapterDataObserver if not already registered
+        if (!isAdapterObserverRegistered) {
+            deckAdapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
+                override fun onChanged() {
+                    updateDoneButtonVisibility() // Update visibility when data changes
+                }
+            })
+            isAdapterObserverRegistered = true
+        }
+    }
+
+    private fun showDiscardChangesDialog() {
+        DiscardChangesDialog.showDialog(
+            context = this@CardAnalysisWidgetConfig,
+            positiveMethod = {
+                // Discard changes and finish the activity
+                hasUnsavedChanges = false
+                finish()
+            }
+        )
+    }
+
+    private fun updateCallbackState() {
+        onBackPressedCallback.isEnabled = hasUnsavedChanges
+    }
+
+    // Call this method when there are unsaved changes
+    private fun setUnsavedChanges(unsaved: Boolean) {
+        hasUnsavedChanges = unsaved
+        updateCallbackState()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        unregisterReceiverSilently(widgetRemovedReceiver)
+    }
+
+    override val baseSnackbarBuilder: SnackbarBuilder = {
+        anchorView = findViewById<FloatingActionButton>(R.id.fabWidgetDeckPicker)
+    }
+
+    private fun setupDoneButton() {
+        val doneButton = findViewById<Button>(R.id.submit_button)
+        val saveText = getString(R.string.save).uppercase()
+
+        // Set the button text and click listener only once during initialization
+        doneButton.text = saveText
+        doneButton.setOnClickListener {
+            saveSelectedDecksToPreferencesCardAnalysisWidget()
+            hasUnsavedChanges = false
+            setUnsavedChanges(false)
+
+            val selectedDeckIds = cardAnalysisWidgetPreferences.getSelectedDeckIdFromPreferences(appWidgetId)
+
+            val appWidgetManager = AppWidgetManager.getInstance(this)
+            CardAnalysisWidget.updateWidget(this, appWidgetManager, appWidgetId, selectedDeckIds)
+
+            val resultValue = Intent().putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId)
+            setResult(RESULT_OK, resultValue)
+
+            sendBroadcast(Intent(this, CardAnalysisWidget::class.java))
+
+            finish()
+        }
+
+        // Initially set the visibility based on the number of selected decks
+        updateDoneButtonVisibility()
+    }
+
+    private fun updateDoneButtonVisibility() {
+        val doneButton = findViewById<Button>(R.id.submit_button)
+        doneButton.isVisible = deckAdapter.itemCount != 0
+    }
+
+    /** Updates the visibility of the FloatingActionButton based on the number of selected decks */
+    private fun updateFabVisibility() {
+        lifecycleScope.launch {
+            // Directly check if there's exactly one deck selected
+            val selectedDeckCount = deckAdapter.itemCount
+
+            // Find the FloatingActionButton by its ID
+            val fab = findViewById<FloatingActionButton>(R.id.fabWidgetDeckPicker)
+
+            // Make the FAB visible only if no deck is selected (allow adding one deck)
+            fab.isVisible = selectedDeckCount == 0
+        }
+    }
+
+    private suspend fun isDefaultDeckEmpty(): Boolean {
+        return DeckUtils.isDefaultDeckEmpty()
+    }
+
+    /** Updates the view according to the saved preference for appWidgetId.*/
+    fun updateViewWithSavedPreferences() {
+        val selectedDeckIds = cardAnalysisWidgetPreferences.getSelectedDeckIdFromPreferences(appWidgetId)
+        if (selectedDeckIds.isNotEmpty()) {
+            lifecycleScope.launch {
+                val decks = fetchDecks()
+                val selectedDecks = decks.filter { it.deckId in selectedDeckIds }
+                selectedDecks.forEach { deckAdapter.addDeck(it) }
+                updateViewVisibility()
+                updateFabVisibility()
+                setupDoneButton()
+            }
+        }
+    }
+
+    /** Asynchronously displays the list of deck in the selection dialog. */
+    private fun showDeckSelectionDialog() {
+        lifecycleScope.launch {
+            val decks = fetchDecks()
+            displayDeckSelectionDialog(decks)
+        }
+    }
+
+    /** Returns the list of standard deck. */
+    private suspend fun fetchDecks(): List<SelectableDeck> {
+        return withContext(Dispatchers.IO) {
+            SelectableDeck.fromCollection(includeFiltered = false)
+        }
+    }
+
+    /** Displays the deck selection dialog with the provided list of decks. */
+    private fun displayDeckSelectionDialog(decks: List<SelectableDeck>) {
+        val dialog = DeckSelectionDialog.newInstance(
+            title = getString(R.string.select_deck_title),
+            summaryMessage = null,
+            keepRestoreDefaultButton = false,
+            decks = decks
+        )
+        dialog.show(supportFragmentManager, "DeckSelectionDialog")
+    }
+
+    /** Called when a deck is selected from the deck selection dialog. */
+    override fun onDeckSelected(deck: SelectableDeck?) {
+        if (deck == null) {
+            return
+        }
+
+        // Check if the deck is being added to a fully occupied selection
+        if (deckAdapter.itemCount >= MAX_DECKS_ALLOWED) {
+            showSnackbar(R.string.deck_limit_one)
+        } else {
+            // Add the deck and update views
+            deckAdapter.addDeck(deck)
+            updateViewVisibility()
+            updateFabVisibility()
+            setupDoneButton()
+            hasUnsavedChanges = true
+            setUnsavedChanges(true)
+
+            if (deckAdapter.itemCount == MAX_DECKS_ALLOWED) {
+                showSnackbar(R.string.deck_limit_one) // Show Snackbar if the limit is now reached
+            }
+        }
+    }
+
+    /** Updates the visibility of the "no decks" placeholder and the widget configuration container */
+    fun updateViewVisibility() {
+        val noDecksPlaceholder = findViewById<View>(R.id.no_decks_placeholder)
+        val widgetConfigContainer = findViewById<View>(R.id.widgetConfigContainer)
+
+        noDecksPlaceholder.isVisible = deckAdapter.itemCount == 0
+        widgetConfigContainer.isVisible = deckAdapter.itemCount > 0
+    }
+
+    fun saveSelectedDecksToPreferencesCardAnalysisWidget() {
+        val selectedDecks = deckAdapter.deckIds.map { it }
+        cardAnalysisWidgetPreferences.saveSelectedDeck(appWidgetId, selectedDecks.map { it.toString() })
+
+        val updateIntent = Intent(this, CardAnalysisWidget::class.java).apply {
+            action = AppWidgetManager.ACTION_APPWIDGET_UPDATE
+            putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, intArrayOf(appWidgetId))
+
+            putExtra("card_analysis_widget_selected_deck_ids", selectedDecks.toList().toLongArray())
+        }
+
+        sendBroadcast(updateIntent)
+    }
+
+    /** BroadcastReceiver to handle widget removal. */
+    private val widgetRemovedReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context?, intent: Intent?) {
+            if (intent?.action != AppWidgetManager.ACTION_APPWIDGET_DELETED) {
+                return
+            }
+
+            val appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID)
+            if (appWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
+                return
+            }
+
+            context?.let { cardAnalysisWidgetPreferences.deleteDeckData(appWidgetId) }
+        }
+    }
+
+    private suspend fun isCollectionEmpty(): Boolean {
+        val tree = withCol { sched.deckDueTree() }
+        if (tree.children.size == 1 && tree.children[0].did == 1L) {
+            return isDefaultDeckEmpty()
+        }
+        return false
+    }
+}
+
+fun ContextWrapper.unregisterReceiverSilently(receiver: BroadcastReceiver) {
+    try {
+        unregisterReceiver(receiver)
+    } catch (e: IllegalArgumentException) {
+        Timber.d(e, "unregisterReceiverSilently")
+    }
+}

AnkiDroid/src/main/java/com/ichi2/widget/cardanalysis/CardAnalysisWidgetPreferences.kt

@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c) 2024 Anoop <xenonnn4w@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.ichi2.widget.cardanalysis
+
+import android.content.Context
+import androidx.core.content.edit
+
+class CardAnalysisWidgetPreferences(context: Context) {
+
+    /**
+     * Prefix for the SharedPreferences key used to store the selected deck for the Card Analysis Widget.
+     * The full key is constructed by appending the appWidgetId to this prefix, ensuring that each
+     * widget instance has a unique key. This approach helps prevent typos and ensures consistency
+     * across the codebase when accessing or modifying the stored deck selections.
+     */
+
+    private val cardAnalysisWidgetSharedPreferences = context.getSharedPreferences("CardAnalysisExtraWidgetPrefs", Context.MODE_PRIVATE)
+
+    /**
+     * Deletes the selected deck ID from the shared preferences for the given widget ID.
+     */
+    fun deleteDeckData(appWidgetId: Int) {
+        cardAnalysisWidgetSharedPreferences.edit {
+            remove(getCardAnalysisExtraWidgetKey(appWidgetId))
+        }
+    }
+
+    fun getSelectedDeckIdFromPreferences(appWidgetId: Int): LongArray {
+        val selectedDeckString = cardAnalysisWidgetSharedPreferences.getString(
+            getCardAnalysisExtraWidgetKey(appWidgetId),
+            ""
+        )
+        return if (!selectedDeckString.isNullOrEmpty()) {
+            selectedDeckString.split(",").map { it.toLong() }.toLongArray()
+        } else {
+            longArrayOf()
+        }
+    }
+
+    fun saveSelectedDeck(appWidgetId: Int, selectedDeck: List<String>) {
+        cardAnalysisWidgetSharedPreferences.edit {
+            putString(getCardAnalysisExtraWidgetKey(appWidgetId), selectedDeck.joinToString(","))
+        }
+    }
+}
+
+/**
+ * Generates the key for the shared preferences for the given widget ID.
+ */
+private fun getCardAnalysisExtraWidgetKey(appWidgetId: Int): String {
+    return "card_analysis_extra_widget_selected_deck_$appWidgetId"
+}

AnkiDroid/src/main/java/com/ichi2/widget/deckpicker/DeckPickerWidget.kt

@@ -18,6 +18,7 @@ package com.ichi2.widget.deckpicker
 
 import android.app.PendingIntent
 import android.appwidget.AppWidgetManager
+import android.appwidget.AppWidgetManager.ACTION_APPWIDGET_UPDATE
 import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
@@ -31,7 +32,6 @@ import com.ichi2.anki.analytics.UsageAnalytics
 import com.ichi2.anki.pages.DeckOptions
 import com.ichi2.widget.ACTION_UPDATE_WIDGET
 import com.ichi2.widget.AnalyticsWidgetProvider
-import com.ichi2.widget.WidgetPreferences
 import com.ichi2.widget.cancelRecurringAlarm
 import com.ichi2.widget.setRecurringAlarm
 import kotlinx.coroutines.launch
@@ -67,11 +67,6 @@ data class DeckPickerWidgetData(
 class DeckPickerWidget : AnalyticsWidgetProvider() {
 
     companion object {
-        /**
-         * Action identifier to trigger updating the app widget.
-         * This constant is used to trigger the update of all widgets by the AppWidgetManager.
-         */
-        const val ACTION_APPWIDGET_UPDATE = AppWidgetManager.ACTION_APPWIDGET_UPDATE
 
         /**
          * Key used for passing the selected deck IDs in the intent extras.
@@ -159,8 +154,8 @@ class DeckPickerWidget : AnalyticsWidgetProvider() {
             Timber.d("AppWidgetIds to update: ${appWidgetIds.joinToString(", ")}")
 
             for (appWidgetId in appWidgetIds) {
-                val widgetPreferences = WidgetPreferences(context)
-                val deckIds = widgetPreferences.getSelectedDeckIdsFromPreferencesDeckPickerWidget(appWidgetId)
+                val widgetPreferences = DeckPickerWidgetPreferences(context)
+                val deckIds = widgetPreferences.getSelectedDeckIdsFromPreferences(appWidgetId)
                 updateWidget(context, appWidgetManager, appWidgetId, deckIds)
             }
         }
@@ -172,13 +167,13 @@ class DeckPickerWidget : AnalyticsWidgetProvider() {
         appWidgetIds: IntArray,
         usageAnalytics: UsageAnalytics
     ) {
-        Timber.d("Performing widget update for appWidgetIds: ${appWidgetIds.joinToString(", ")}")
+        Timber.d("Performing widget update for appWidgetIds: %s", appWidgetIds)
 
-        val widgetPreferences = WidgetPreferences(context)
+        val widgetPreferences = DeckPickerWidgetPreferences(context)
 
         for (widgetId in appWidgetIds) {
             Timber.d("Updating widget with ID: $widgetId")
-            val selectedDeckIds = widgetPreferences.getSelectedDeckIdsFromPreferencesDeckPickerWidget(widgetId)
+            val selectedDeckIds = widgetPreferences.getSelectedDeckIdsFromPreferences(widgetId)
 
             /**Explanation of behavior when selectedDeckIds is empty
              * If selectedDeckIds is empty, the widget will retain the previous deck list.
@@ -204,7 +199,7 @@ class DeckPickerWidget : AnalyticsWidgetProvider() {
         }
         super.onReceive(context, intent)
 
-        val widgetPreferences = WidgetPreferences(context)
+        val widgetPreferences = DeckPickerWidgetPreferences(context)
 
         when (intent.action) {
             ACTION_APPWIDGET_UPDATE -> {
@@ -236,7 +231,7 @@ class DeckPickerWidget : AnalyticsWidgetProvider() {
                 if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
                     Timber.d("Deleting widget with ID: $appWidgetId")
                     cancelRecurringAlarm(context, appWidgetId, DeckPickerWidget::class.java)
-                    widgetPreferences.deleteDeckPickerWidgetData(appWidgetId)
+                    widgetPreferences.deleteDeckData(appWidgetId)
                 } else {
                     Timber.e("Invalid widget ID received in ACTION_APPWIDGET_DELETED")
                 }
@@ -265,11 +260,11 @@ class DeckPickerWidget : AnalyticsWidgetProvider() {
             return
         }
 
-        val widgetPreferences = WidgetPreferences(context)
+        val widgetPreferences = DeckPickerWidgetPreferences(context)
 
         appWidgetIds?.forEach { widgetId ->
             cancelRecurringAlarm(context, widgetId, DeckPickerWidget::class.java)
-            widgetPreferences.deleteDeckPickerWidgetData(widgetId)
+            widgetPreferences.deleteDeckData(widgetId)
         }
     }
 }

AnkiDroid/src/main/java/com/ichi2/widget/deckpicker/DeckPickerWidgetConfig.kt

@@ -35,6 +35,7 @@ import com.google.android.material.floatingactionbutton.FloatingActionButton
 import com.google.android.material.snackbar.Snackbar
 import com.ichi2.anki.AnkiActivity
 import com.ichi2.anki.CollectionManager.withCol
+import com.ichi2.anki.DeckUtils
 import com.ichi2.anki.R
 import com.ichi2.anki.dialogs.DeckSelectionDialog
 import com.ichi2.anki.dialogs.DeckSelectionDialog.DeckSelectionListener
@@ -45,7 +46,6 @@ import com.ichi2.anki.snackbar.BaseSnackbarBuilderProvider
 import com.ichi2.anki.snackbar.SnackbarBuilder
 import com.ichi2.anki.snackbar.showSnackbar
 import com.ichi2.widget.WidgetConfigScreenAdapter
-import com.ichi2.widget.WidgetPreferences
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -61,7 +61,7 @@ class DeckPickerWidgetConfig : AnkiActivity(), DeckSelectionListener, BaseSnackb
 
     private var appWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID
     lateinit var deckAdapter: WidgetConfigScreenAdapter
-    private lateinit var deckPickerWidgetPreferences: WidgetPreferences
+    private lateinit var deckPickerWidgetPreferences: DeckPickerWidgetPreferences
 
     /**
      * Maximum number of decks allowed in the widget.
@@ -84,7 +84,7 @@ class DeckPickerWidgetConfig : AnkiActivity(), DeckSelectionListener, BaseSnackb
 
         setContentView(R.layout.widget_deck_picker_config)
 
-        deckPickerWidgetPreferences = WidgetPreferences(this)
+        deckPickerWidgetPreferences = DeckPickerWidgetPreferences(this)
 
         appWidgetId = intent.extras?.getInt(
             AppWidgetManager.EXTRA_APPWIDGET_ID,
@@ -225,7 +225,7 @@ class DeckPickerWidgetConfig : AnkiActivity(), DeckSelectionListener, BaseSnackb
             hasUnsavedChanges = false
             setUnsavedChanges(false)
 
-            val selectedDeckIds = deckPickerWidgetPreferences.getSelectedDeckIdsFromPreferencesDeckPickerWidget(appWidgetId)
+            val selectedDeckIds = deckPickerWidgetPreferences.getSelectedDeckIdsFromPreferences(appWidgetId)
 
             val appWidgetManager = AppWidgetManager.getInstance(this)
             DeckPickerWidget.updateWidget(this, appWidgetManager, appWidgetId, selectedDeckIds)
@@ -281,18 +281,12 @@ class DeckPickerWidgetConfig : AnkiActivity(), DeckSelectionListener, BaseSnackb
     }
 
     private suspend fun isDefaultDeckEmpty(): Boolean {
-        val defaultDeckId = 1L
-        val decks = withContext(Dispatchers.IO) {
-            withCol { decks }
-        }
-        val deckIds = decks.deckAndChildIds(defaultDeckId)
-        val totalCardCount = decks.cardCount(*deckIds.toLongArray(), includeSubdecks = true)
-        return totalCardCount == 0
+        return DeckUtils.isDefaultDeckEmpty()
     }
 
     /** Updates the view according to the saved preference for appWidgetId.*/
     fun updateViewWithSavedPreferences() {
-        val selectedDeckIds = deckPickerWidgetPreferences.getSelectedDeckIdsFromPreferencesDeckPickerWidget(appWidgetId)
+        val selectedDeckIds = deckPickerWidgetPreferences.getSelectedDeckIdsFromPreferences(appWidgetId)
         if (selectedDeckIds.isNotEmpty()) {
             lifecycleScope.launch {
                 val decks = fetchDecks()
@@ -447,7 +441,7 @@ class DeckPickerWidgetConfig : AnkiActivity(), DeckSelectionListener, BaseSnackb
                 return
             }
 
-            context?.let { deckPickerWidgetPreferences.deleteDeckPickerWidgetData(appWidgetId) }
+            context?.let { deckPickerWidgetPreferences.deleteDeckData(appWidgetId) }
         }
     }
 

AnkiDroid/src/main/java/com/ichi2/widget/deckpicker/DeckPickerWidgetPreferences.kt

@@ -14,18 +14,12 @@
  *  this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package com.ichi2.widget
+package com.ichi2.widget.deckpicker
 
 import android.content.Context
 import androidx.core.content.edit
 
-/**
- * This class is currently used for the Deck Picker Widget but is designed to be extendable
- * for use with other widgets, such as the Card Analysis Widget, in the future.
- *
- * @param context the context used to access the shared preferences
- */
-class WidgetPreferences(context: Context) {
+class DeckPickerWidgetPreferences(context: Context) {
 
     /**
      * Prefix for the SharedPreferences key used to store the selected decks for the DeckPickerWidget.
@@ -39,7 +33,7 @@ class WidgetPreferences(context: Context) {
     /**
      * Deletes the selected deck IDs from the shared preferences for the given widget ID.
      */
-    fun deleteDeckPickerWidgetData(appWidgetId: Int) {
+    fun deleteDeckData(appWidgetId: Int) {
         deckPickerSharedPreferences.edit {
             remove(getDeckPickerWidgetKey(appWidgetId))
         }
@@ -49,7 +43,7 @@ class WidgetPreferences(context: Context) {
      * Retrieves the selected deck IDs from the shared preferences for the given widget ID.
      * Note: There's no guarantee that these IDs still represent decks that exist at the time of execution.
      */
-    fun getSelectedDeckIdsFromPreferencesDeckPickerWidget(appWidgetId: Int): LongArray {
+    fun getSelectedDeckIdsFromPreferences(appWidgetId: Int): LongArray {
         val selectedDecksString = deckPickerSharedPreferences.getString(getDeckPickerWidgetKey(appWidgetId), "")
         return if (!selectedDecksString.isNullOrEmpty()) {
             selectedDecksString.split(",").map { it.toLong() }.toLongArray()

AnkiDroid/src/main/res/layout/widget_card_analysis.xml

@@ -0,0 +1,65 @@
+<RelativeLayout android:id="@+id/widget_deck_picker"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:background="?attr/colorPrimaryInverse"
+    android:clickable="true"
+    android:focusable="false"
+    android:theme="@style/Theme.Material3.DynamicColors.DayNight">
+
+    <LinearLayout
+        android:id="@+id/cardAnalysisDataHolder"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="?attr/colorPrimaryContainer"
+        android:orientation="horizontal"
+        android:padding="20dp">
+
+        <TextView
+            android:id="@+id/deckNew_card_analysis_widget"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:gravity="center"
+            android:textColor="@color/flag_reviewer_blue"
+            android:textSize="24sp"
+            android:textStyle="bold"
+            tools:text="50" />
+
+        <TextView
+            android:id="@+id/deckLearn_card_analysis_widget"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:gravity="center"
+            android:textColor="@color/flag_reviewer_red"
+            android:textSize="24sp"
+            android:textStyle="bold"
+            tools:text="12" />
+
+        <TextView
+            android:id="@+id/deckDue_card_analysis_widget"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:gravity="center"
+            android:textColor="@color/flag_reviewer_green"
+            android:textSize="24sp"
+            android:textStyle="bold"
+            tools:text="57" />
+    </LinearLayout>
+
+    <TextView
+        android:id="@+id/deckNameCardAnalysis"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="70dp"
+        android:gravity="center"
+        android:padding="20dp"
+        android:paddingBottom="5dp"
+        android:textColor="?android:attr/textColorPrimary"
+        android:textSize="24sp"
+        tools:text="Default" />
+
+</RelativeLayout>

AnkiDroid/src/main/res/layout/widget_card_analysis_drawable_v31.xml

@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<LinearLayout xmlns:tools="http://schemas.android.com/tools"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="?attr/colorPrimaryInverse"
+    android:orientation="vertical"
+    android:theme="@style/Theme.Material3.DynamicColors.DayNight">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="?attr/colorPrimaryContainer"
+        android:orientation="horizontal"
+        android:padding="20dp">
+
+        <TextView
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:gravity="center"
+            android:text="85"
+            android:textColor="@color/flag_reviewer_blue"
+            android:textSize="24sp"
+            android:textStyle="bold"
+            tools:ignore="HardcodedText" />
+
+        <TextView
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:gravity="center"
+            android:text="38"
+            android:textColor="@color/flag_reviewer_red"
+            android:textSize="24sp"
+            android:textStyle="bold"
+            tools:ignore="HardcodedText" />
+
+        <TextView
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:gravity="center"
+            android:text="84"
+            android:textColor="@color/flag_reviewer_green"
+            android:textSize="24sp"
+            android:textStyle="bold"
+            tools:ignore="HardcodedText" />
+    </LinearLayout>
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:padding="20dp"
+        android:paddingBottom="5dp"
+        android:text="@string/deck1Name_deck_picker_widget"
+        android:textColor="?android:attr/textColorPrimary"
+        android:textSize="24sp" />
+
+</LinearLayout>

AnkiDroid/src/main/res/values/08-widget.xml

@@ -39,8 +39,9 @@
 
     <string name="widget_add_note_button">Add new AnkiDroid note</string>
     <string name="deck_picker_widget_description">Deck Picker</string>
+    <string name="card_analysis_extra_widget_description">Card Analysis</string>
 
-    <!-- Strings to explain usage in Deck Picker Widget Configuration screen -->
+    <!-- Strings to explain usage in Deck Picker and Card Analysis Widget Configuration screen -->
     <string name="select_deck_title" comment="Title for Deck Selection Dialog">Select decks</string>
     <string name="no_selected_deck_placeholder_title" comment="Placeholder title when no decks are selected">Select decks to display in the widget. Select decks with the + icon.</string>
     <string name="deck_removed_from_widget" comment="Snackbar when deck is removed from widget">Deck removed</string>
@@ -49,5 +50,6 @@
         <item quantity="one">You can select up to %d deck.</item>
         <item quantity="other">You can select up to %d decks.</item>
     </plurals>
+    <string name="deck_limit_one">You may only select one deck</string>
 
 </resources>

AnkiDroid/src/main/res/xml/widget_provider_card_analysis.xml

@@ -0,0 +1,28 @@
+<!-- JPG type of file used in previewImage property because the SVG format is not supported on all devices.
+     The widths and heights parameters are determined as follows:
+     The default is 3 cells in width and 2 in height.
+     Following https://developer.android.com/develop/ui/views/appwidgets/layouts#anatomy_determining_size
+     we used the portrait mode cell size for the width and the landscape mode cell size for the height. Leading to:
+     * height between 102 and 315
+     * width 203 and 276 -->
+
+<!-- TODO: Use updatePeriodMillis instead of the 10-minute alarm for simpler widget updates.-->
+
+<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
+    android:initialKeyguardLayout="@layout/widget_card_analysis"
+    android:initialLayout="@layout/widget_card_analysis"
+    android:configure="com.ichi2.widget.cardanalysis.CardAnalysisWidgetConfig"
+    android:widgetFeatures="reconfigurable"
+    android:minWidth="203dp"
+    android:minHeight="102dp"
+    android:minResizeWidth="203dp"
+    android:minResizeHeight="102dp"
+    android:maxResizeWidth="276dp"
+    android:maxResizeHeight="315dp"
+    android:previewImage="@drawable/widget_card_analysis_drawable"
+    android:previewLayout="@layout/widget_card_analysis_drawable_v31"
+    android:resizeMode="horizontal|vertical"
+    android:targetCellHeight="2"
+    android:targetCellWidth="3"
+    android:widgetCategory="home_screen"
+    />

AnkiDroid/src/test/java/com/ichi2/anki/widget/cardanalysis/CardAnalysisWidgetConfigTest.kt

@@ -0,0 +1,155 @@
+/*
+ *  Copyright (c) 2024 Anoop <xenonnn4w@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.ichi2.anki.widget.cardanalysis
+
+import android.appwidget.AppWidgetManager
+import android.content.Intent
+import android.view.View
+import androidx.recyclerview.widget.RecyclerView
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.ichi2.anki.R
+import com.ichi2.anki.RobolectricTest
+import com.ichi2.anki.dialogs.DeckSelectionDialog
+import com.ichi2.widget.cardanalysis.CardAnalysisWidgetConfig
+import com.ichi2.widget.cardanalysis.CardAnalysisWidgetPreferences
+import org.hamcrest.MatcherAssert.assertThat
+import org.hamcrest.Matchers.equalTo
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+
+@RunWith(AndroidJUnit4::class)
+class CardAnalysisWidgetConfigTest : RobolectricTest() {
+
+    private lateinit var activity: CardAnalysisWidgetConfig
+    private lateinit var widgetPreferences: CardAnalysisWidgetPreferences
+
+    /**
+     * Sets up the test environment before each test.
+     *
+     * Initializes the `CardAnalysisWidgetConfig` activity and associated components like
+     * `WidgetPreferences`. This setup is executed before each test method.
+     */
+    @Before
+    override fun setUp() {
+        super.setUp()
+        val intent = Intent(ApplicationProvider.getApplicationContext(), CardAnalysisWidgetConfig::class.java).apply {
+            putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, 1)
+        }
+
+        activity = Robolectric.buildActivity(CardAnalysisWidgetConfig::class.java, intent)
+            .create()
+            .start()
+            .resume()
+            .get()
+
+        // Initialize widget preferences
+        widgetPreferences = CardAnalysisWidgetPreferences(ApplicationProvider.getApplicationContext())
+
+        // Ensure deckAdapter is initialized
+        activity.initializeUIComponents()
+    }
+
+    /**
+     * Tests the functionality of saving selected decks to preferences.
+     *
+     * This test adds a deck to the adapter and verifies if it gets correctly saved to the
+     * `WidgetPreferences`.
+     */
+    @Test
+    fun testSaveSelectedDecksToPreferences() {
+        // Add decks to adapter
+        val deck1 = DeckSelectionDialog.SelectableDeck(1, "Deck 1")
+        activity.deckAdapter.addDeck(deck1)
+
+        // Save selected decks
+        activity.saveSelectedDecksToPreferencesCardAnalysisWidget()
+
+        // Verify saved decks
+        val selectedDeckIds = widgetPreferences.getSelectedDeckIdFromPreferences(1).toList()
+        assertThat(selectedDeckIds.contains(deck1.deckId), equalTo(true))
+    }
+
+    /**
+     * Tests the loading of saved preferences into the activity's view.
+     *
+     * This test saves decks to preferences, then loads them into the activity and checks if the
+     * `RecyclerView` displays the correct number of items based on the saved preferences.
+     */
+    @Test
+    fun testLoadSavedPreferences() {
+        // Save decks to preferences
+        val deckIds = listOf(1L)
+        widgetPreferences.saveSelectedDeck(1, deckIds.map { it.toString() })
+
+        // Load preferences
+        activity.updateViewWithSavedPreferences()
+
+        // Ensure all tasks on the UI thread are completed
+        Robolectric.flushForegroundThreadScheduler()
+
+        // Get the RecyclerView and its adapter
+        val recyclerView = activity.findViewById<RecyclerView>(R.id.recyclerViewSelectedDecks)
+        val adapter = recyclerView.adapter
+
+        // Verify the adapter has the correct item count
+        assertThat(adapter?.itemCount, equalTo(deckIds.size))
+    }
+
+    /**
+     * Tests the visibility of different views based on the selected decks.
+     *
+     * This test checks the visibility of the placeholder and configuration container views
+     * before and after adding a deck.
+     */
+    @Test
+    fun testUpdateViewVisibility() {
+        val noDecksPlaceholder = activity.findViewById<View>(R.id.no_decks_placeholder)
+        val widgetConfigContainer = activity.findViewById<View>(R.id.widgetConfigContainer)
+
+        // Initially, no decks should be selected
+        activity.updateViewVisibility()
+        assertThat(noDecksPlaceholder.visibility, equalTo(View.VISIBLE))
+        assertThat(widgetConfigContainer.visibility, equalTo(View.GONE))
+
+        // Add a deck and update view visibility
+        val deck = DeckSelectionDialog.SelectableDeck(1, "Deck 1")
+        activity.deckAdapter.addDeck(deck)
+        activity.updateViewVisibility()
+
+        assertThat(noDecksPlaceholder.visibility, equalTo(View.GONE))
+        assertThat(widgetConfigContainer.visibility, equalTo(View.VISIBLE))
+    }
+
+    /**
+     * Tests the selection of a deck.
+     *
+     * This test verifies that when a deck is selected, it gets added to the adapter and displayed
+     * in the `RecyclerView`.
+     */
+    @Test
+    fun testOnDeckSelected() {
+        val deck = DeckSelectionDialog.SelectableDeck(1, "Deck 1")
+        activity.onDeckSelected(deck)
+
+        // Verify deck is added to adapter
+        val recyclerView = activity.findViewById<RecyclerView>(R.id.recyclerViewSelectedDecks)
+        assertThat(recyclerView.adapter?.itemCount, equalTo(1))
+    }
+}

AnkiDroid/src/test/java/com/ichi2/anki/widget/deckpicker/DeckPickerWidgetConfigTest.kt

@@ -19,16 +19,14 @@ package com.ichi2.anki.widget.deckpicker
 import android.appwidget.AppWidgetManager
 import android.content.Intent
 import android.view.View
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.LifecycleRegistry
 import androidx.recyclerview.widget.RecyclerView
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.ichi2.anki.R
 import com.ichi2.anki.RobolectricTest
 import com.ichi2.anki.dialogs.DeckSelectionDialog
-import com.ichi2.widget.WidgetPreferences
 import com.ichi2.widget.deckpicker.DeckPickerWidgetConfig
+import com.ichi2.widget.deckpicker.DeckPickerWidgetPreferences
 import org.hamcrest.MatcherAssert.assertThat
 import org.hamcrest.Matchers.equalTo
 import org.junit.Before
@@ -40,14 +38,13 @@ import org.robolectric.Robolectric
 class DeckPickerWidgetConfigTest : RobolectricTest() {
 
     private lateinit var activity: DeckPickerWidgetConfig
-    private lateinit var lifecycle: LifecycleRegistry
-    private lateinit var widgetPreferences: WidgetPreferences
+    private lateinit var widgetPreferences: DeckPickerWidgetPreferences
 
     /**
      * Sets up the test environment before each test.
      *
      * Initializes the `DeckPickerWidgetConfig` activity and associated components like
-     * `LifecycleRegistry` and `WidgetPreferences`. This setup is executed before each test method.
+     * `WidgetPreferences`. This setup is executed before each test method.
      */
     @Before
     override fun setUp() {
@@ -62,10 +59,7 @@ class DeckPickerWidgetConfigTest : RobolectricTest() {
             .resume()
             .get()
 
-        lifecycle = LifecycleRegistry(activity)
-        lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_CREATE)
-
-        widgetPreferences = WidgetPreferences(ApplicationProvider.getApplicationContext())
+        widgetPreferences = DeckPickerWidgetPreferences(ApplicationProvider.getApplicationContext())
 
         // Ensure deckAdapter is initialized
         activity.initializeUIComponents()
@@ -87,7 +81,7 @@ class DeckPickerWidgetConfigTest : RobolectricTest() {
         activity.saveSelectedDecksToPreferencesDeckPickerWidget()
 
         // Verify saved decks
-        val selectedDeckIds = widgetPreferences.getSelectedDeckIdsFromPreferencesDeckPickerWidget(1).toList()
+        val selectedDeckIds = widgetPreferences.getSelectedDeckIdsFromPreferences(1).toList()
         assertThat(selectedDeckIds.contains(deck1.deckId), equalTo(true))
     }
 

AnkiDroid/src/test/java/com/ichi2/testutils/ActivityList.kt

@@ -47,6 +47,7 @@ import com.ichi2.anki.services.ReminderService.Companion.getReviewDeckIntent
 import com.ichi2.anki.ui.windows.managespace.ManageSpaceActivity
 import com.ichi2.anki.ui.windows.permissions.PermissionsActivity
 import com.ichi2.testutils.ActivityList.ActivityLaunchParam.Companion.get
+import com.ichi2.widget.cardanalysis.CardAnalysisWidgetConfig
 import com.ichi2.widget.deckpicker.DeckPickerWidgetConfig
 import org.robolectric.Robolectric
 import org.robolectric.android.controller.ActivityController
@@ -90,7 +91,8 @@ object ActivityList {
             get(CardViewerActivity::class.java),
             get(InstantNoteEditorActivity::class.java),
             get(MultimediaActivity::class.java),
-            get(DeckPickerWidgetConfig::class.java)
+            get(DeckPickerWidgetConfig::class.java),
+            get(CardAnalysisWidgetConfig::class.java)
         )
     }