Fixes #3169: Item selection interaction text change and checkboxes should be disabled on selection

app/BUILD.bazel

@@ -223,6 +223,7 @@ VIEW_MODELS_WITH_RESOURCE_IMPORTS = [
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/MathExpressionInteractionsViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/PreviousResponsesHeaderViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/RatioExpressionInputInteractionViewModel.kt",
+    "src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/SubmittedAnswerViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/TextInputViewModel.kt",
     "src/main/java/org/oppia/android/app/profile/AddProfileViewModel.kt",
@@ -316,7 +317,6 @@ VIEW_MODELS = [
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/ReplayButtonViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/ReturnToTopicButtonViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionContentViewModel.kt",
-    "src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/StateItemViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/itemviewmodel/SubmitButtonViewModel.kt",
     "src/main/java/org/oppia/android/app/player/state/StateViewModel.kt",
@@ -469,6 +469,7 @@ BINDING_ADAPTERS_WITH_RESOURCE_IMPORTS = [
 
 # keep sorted
 BINDING_ADAPTERS = [
+    "src/main/java/org/oppia/android/app/databinding/AppCompatCheckBoxBindingAdapters.java",
     "src/main/java/org/oppia/android/app/databinding/ConstraintLayoutAdapters.java",
     "src/main/java/org/oppia/android/app/databinding/EditTextBindingAdapters.java",
     "src/main/java/org/oppia/android/app/databinding/GuidelineBindingAdapters.java",

app/src/main/AndroidManifest.xml

@@ -194,6 +194,7 @@
       android:name=".app.story.StoryActivity"
       android:label="@string/story_activity_title"
       android:theme="@style/OppiaThemeWithoutActionBar" />
+    <activity android:name=".app.testing.AppCompatCheckBoxBindingAdaptersTestActivity" />
     <activity android:name=".app.testing.AudioFragmentTestActivity" />
     <activity android:name=".app.testing.BindableAdapterTestActivity" />
     <activity android:name=".app.testing.ConceptCardFragmentTestActivity" />

app/src/main/java/org/oppia/android/app/activity/ActivityComponentImpl.kt

@@ -55,6 +55,7 @@ import org.oppia.android.app.settings.profile.ProfileResetPinActivity
 import org.oppia.android.app.splash.SplashActivity
 import org.oppia.android.app.story.StoryActivity
 import org.oppia.android.app.testing.AdministratorControlsFragmentTestActivity
+import org.oppia.android.app.testing.AppCompatCheckBoxBindingAdaptersTestActivity
 import org.oppia.android.app.testing.AudioFragmentTestActivity
 import org.oppia.android.app.testing.ConceptCardFragmentTestActivity
 import org.oppia.android.app.testing.DragDropTestActivity
@@ -114,6 +115,10 @@ interface ActivityComponentImpl :
   fun inject(administratorControlsActivity: AdministratorControlsActivity)
   fun inject(administratorControlsFragmentTestActivity: AdministratorControlsFragmentTestActivity)
   fun inject(adminPinActivity: AdminPinActivity)
+  fun inject(
+    appCompatCheckBoxBindingAdaptersTestActivity:
+      AppCompatCheckBoxBindingAdaptersTestActivity
+  )
   fun inject(appLanguageActivity: AppLanguageActivity)
   fun inject(appVersionActivity: AppVersionActivity)
   fun inject(audioFragmentTestActivity: AudioFragmentTestActivity)

app/src/main/java/org/oppia/android/app/databinding/AppCompatCheckBoxBindingAdapters.java

@@ -0,0 +1,18 @@
+package org.oppia.android.app.databinding;
+
+import android.content.res.ColorStateList;
+import androidx.annotation.ColorInt;
+import androidx.annotation.NonNull;
+import androidx.appcompat.widget.AppCompatCheckBox;
+import androidx.databinding.BindingAdapter;
+
+/**
+ * Custom data-binding adapters for {@link AppCompatCheckBox}s.
+ */
+public final class AppCompatCheckBoxBindingAdapters {
+  /** Sets the button tint for the specified checkbox, via data-binding. */
+  @BindingAdapter("app:buttonTint")
+  public static void setButtonTint(@NonNull AppCompatCheckBox checkBox, @ColorInt int colorRgb) {
+    checkBox.setSupportButtonTintList(ColorStateList.valueOf(colorRgb));
+  }
+}

app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionContentViewModel.kt

@@ -9,7 +9,8 @@ class SelectionInteractionContentViewModel(
   val htmlContent: SubtitledHtml,
   val hasConversationView: Boolean,
   private val itemIndex: Int,
-  private val selectionInteractionViewModel: SelectionInteractionViewModel
+  private val selectionInteractionViewModel: SelectionInteractionViewModel,
+  val isEnabled: ObservableBoolean
 ) : ObservableViewModel() {
   var isAnswerSelected = ObservableBoolean()
 

app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/SelectionInteractionViewModel.kt

@@ -1,8 +1,10 @@
 package org.oppia.android.app.player.state.itemviewmodel
 
 import androidx.databinding.Observable
+import androidx.databinding.ObservableBoolean
 import androidx.databinding.ObservableField
 import androidx.databinding.ObservableList
+import org.oppia.android.R
 import org.oppia.android.app.model.Interaction
 import org.oppia.android.app.model.InteractionObject
 import org.oppia.android.app.model.SetOfTranslatableHtmlContentIds
@@ -13,6 +15,7 @@ import org.oppia.android.app.model.WrittenTranslationContext
 import org.oppia.android.app.player.state.answerhandling.InteractionAnswerErrorOrAvailabilityCheckReceiver
 import org.oppia.android.app.player.state.answerhandling.InteractionAnswerHandler
 import org.oppia.android.app.player.state.answerhandling.InteractionAnswerReceiver
+import org.oppia.android.app.translation.AppLanguageResourceHandler
 import org.oppia.android.app.viewmodel.ObservableArrayList
 import org.oppia.android.domain.translation.TranslationController
 import javax.inject.Inject
@@ -31,7 +34,8 @@ class SelectionInteractionViewModel private constructor(
   private val interactionAnswerErrorOrAvailabilityCheckReceiver: InteractionAnswerErrorOrAvailabilityCheckReceiver, // ktlint-disable max-line-length
   val isSplitView: Boolean,
   val writtenTranslationContext: WrittenTranslationContext,
-  private val translationController: TranslationController
+  private val translationController: TranslationController,
+  private val resourceHandler: AppLanguageResourceHandler
 ) : StateItemViewModel(ViewType.SELECTION_INTERACTION), InteractionAnswerHandler {
   private val interactionId: String = interaction.id
 
@@ -52,10 +56,21 @@ class SelectionInteractionViewModel private constructor(
       ?: minAllowableSelectionCount
   }
   private val selectedItems: MutableList<Int> = mutableListOf()
+  private val enabledItemsList by lazy {
+    List(choiceSubtitledHtmls.size) {
+      ObservableBoolean(true)
+    }
+  }
   val choiceItems: ObservableList<SelectionInteractionContentViewModel> =
-    computeChoiceItems(choiceSubtitledHtmls, hasConversationView, this)
+    computeChoiceItems(choiceSubtitledHtmls, hasConversationView, this, enabledItemsList)
 
   private val isAnswerAvailable = ObservableField(false)
+  val selectedItemText =
+    ObservableField(
+      resourceHandler.getStringInLocale(
+        R.string.state_fragment_item_selection_no_items_selected_hint_text
+      )
+    )
 
   init {
     val callback: Observable.OnPropertyChangedCallback =
@@ -124,21 +139,23 @@ class SelectionInteractionViewModel private constructor(
       isCurrentlySelected -> {
         selectedItems -= itemIndex
         updateIsAnswerAvailable()
+        updateSelectionText()
+        updateItemSelectability()
         false
       }
       !areCheckboxesBound() -> {
-        // Disable all items to simulate a radio button group.
+        // De-select all other items to simulate a radio button group.
         choiceItems.forEach { item -> item.isAnswerSelected.set(false) }
         selectedItems.clear()
         selectedItems += itemIndex
         updateIsAnswerAvailable()
         true
       }
       selectedItems.size < maxAllowableSelectionCount -> {
-        // TODO(#3624): Add warning to user when they exceed the number of allowable selections or are under the minimum
-        //  number required.
         selectedItems += itemIndex
         updateIsAnswerAvailable()
+        updateSelectionText()
+        updateItemSelectability()
         true
       }
       else -> {
@@ -148,6 +165,38 @@ class SelectionInteractionViewModel private constructor(
     }
   }
 
+  private fun updateSelectionText() {
+    if (selectedItems.size < maxAllowableSelectionCount) {
+      selectedItemText.set(
+        resourceHandler.getStringInLocale(
+          R.string.state_fragment_item_selection_some_items_selected_hint_text
+        )
+      )
+    }
+    if (selectedItems.size == 0) {
+      selectedItemText.set(
+        resourceHandler.getStringInLocale(
+          R.string.state_fragment_item_selection_no_items_selected_hint_text
+        )
+      )
+    }
+    if (selectedItems.size == maxAllowableSelectionCount) {
+      selectedItemText.set(
+        resourceHandler.getStringInLocaleWithWrapping(
+          R.string.state_fragment_item_selection_max_items_selected_hint_text,
+          maxAllowableSelectionCount.toString()
+        )
+      )
+    }
+  }
+
+  private fun updateItemSelectability() {
+    if (selectedItems.size == maxAllowableSelectionCount) {
+      // All non-selected items should be disabled when the limit is reached.
+      enabledItemsList.filterIndexed { idx, _ -> idx !in selectedItems }.forEach { it.set(false) }
+    } else enabledItemsList.forEach { it.set(true) } // Otherwise, all items are available.
+  }
+
   private fun areCheckboxesBound(): Boolean {
     return interactionId == "ItemSelectionInput" && maxAllowableSelectionCount > 1
   }
@@ -161,7 +210,8 @@ class SelectionInteractionViewModel private constructor(
 
   /** Implementation of [StateItemViewModel.InteractionItemFactory] for this view model. */
   class FactoryImpl @Inject constructor(
-    private val translationController: TranslationController
+    private val translationController: TranslationController,
+    private val resourceHandler: AppLanguageResourceHandler
   ) : InteractionItemFactory {
     override fun create(
       entityId: String,
@@ -181,7 +231,8 @@ class SelectionInteractionViewModel private constructor(
         answerErrorReceiver,
         isSplitView,
         writtenTranslationContext,
-        translationController
+        translationController,
+        resourceHandler
       )
     }
   }
@@ -190,15 +241,17 @@ class SelectionInteractionViewModel private constructor(
     private fun computeChoiceItems(
       choiceSubtitledHtmls: List<SubtitledHtml>,
       hasConversationView: Boolean,
-      selectionInteractionViewModel: SelectionInteractionViewModel
+      selectionInteractionViewModel: SelectionInteractionViewModel,
+      enabledItemsList: List<ObservableBoolean>
     ): ObservableArrayList<SelectionInteractionContentViewModel> {
       val observableList = ObservableArrayList<SelectionInteractionContentViewModel>()
       observableList += choiceSubtitledHtmls.mapIndexed { index, subtitledHtml ->
         SelectionInteractionContentViewModel(
           htmlContent = subtitledHtml,
           hasConversationView = hasConversationView,
           itemIndex = index,
-          selectionInteractionViewModel = selectionInteractionViewModel
+          selectionInteractionViewModel = selectionInteractionViewModel,
+          isEnabled = enabledItemsList[index]
         )
       }
       return observableList

app/src/main/java/org/oppia/android/app/testing/AppCompatCheckBoxBindingAdaptersTestActivity.kt

@@ -0,0 +1,15 @@
+package org.oppia.android.app.testing
+
+import android.os.Bundle
+import org.oppia.android.R
+import org.oppia.android.app.activity.ActivityComponentImpl
+import org.oppia.android.app.activity.InjectableAppCompatActivity
+
+/** Test activity for [org.oppia.android.app.databinding.AppCompatCheckBoxBindingAdapters]. */
+class AppCompatCheckBoxBindingAdaptersTestActivity : InjectableAppCompatActivity() {
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    (activityComponent as ActivityComponentImpl).inject(this)
+    setContentView(R.layout.test_app_compat_check_box_bindable_adapter_activity)
+  }
+}

app/src/main/res/layout/item_selection_interaction_items.xml

@@ -29,9 +29,10 @@
       android:layout_height="wrap_content"
       android:checked="@{viewModel.answerSelected}"
       android:clickable="false"
+      android:enabled="@{viewModel.isEnabled}"
       android:focusable="false"
       android:labelFor="@id/item_selection_contents_text_view"
-      app:buttonTint="@color/shared_interaction_selector" />
+      app:buttonTint="@{viewModel.isEnabled ? @color/component_color_shared_item_selection_interaction_enabled_color : @color/component_color_shared_item_selection_interaction_disabled_color}" />
 
     <TextView
       android:id="@+id/item_selection_contents_text_view"
@@ -43,7 +44,7 @@
       android:layout_toEndOf="@+id/item_selection_checkbox"
       android:fontFamily="sans-serif"
       android:text="@{htmlContent}"
-      android:textColor="@{viewModel.isAnswerSelected() ? @color/component_color_shared_selection_interaction_selected_text_color : @color/component_color_shared_selection_interaction_unselected_text_color}"
+      android:textColor="@{viewModel.isEnabled ? @color/component_color_shared_item_selection_interaction_enabled_color : @color/component_color_shared_item_selection_interaction_disabled_color}"
       android:textSize="16sp" />
   </RelativeLayout>
 </layout>

app/src/main/res/layout/selection_interaction_item.xml

@@ -43,7 +43,7 @@
         android:layout_marginTop="4dp"
         android:layout_marginBottom="4dp"
         android:fontFamily="sans-serif-light"
-        android:text="@string/item_selection_text"
+        android:text="@{viewModel.selectedItemText}"
         android:textColor="@color/component_color_shared_primary_text_color"
         android:textSize="14sp"
         android:textStyle="italic"

app/src/main/res/layout/test_app_compat_check_box_bindable_adapter_activity.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <androidx.appcompat.widget.AppCompatCheckBox
+    android:id="@+id/test_check_box"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content" />
+</layout>

app/src/main/res/values/component_colors.xml

@@ -42,6 +42,8 @@
   <color name="component_color_shared_item_selection_interaction_unselected_color">@color/color_palette_item_selection_unselected_color</color>
   <color name="component_color_shared_selection_interaction_selected_text_color">@color/color_palette_item_selection_unselected_text_color</color>
   <color name="component_color_shared_selection_interaction_unselected_text_color">@color/color_palette_item_selection_selected_text_color</color>
+  <color name="component_color_shared_item_selection_interaction_enabled_color">@color/color_palette_item_selection_selected_text_color</color>
+  <color name="component_color_shared_item_selection_interaction_disabled_color">@color/color_palette_disabled_button_background_color</color>
   <color name="component_color_shared_back_forward_arrow_button_color">@color/color_palette_back_forward_arrow_button_color</color>
   <color name="component_color_shared_replay_button_color">@color/color_palette_replay_button_color</color>
   <color name="component_color_shared_progress_bar_solid_color">@color/color_palette_progress_bar_solid_color</color>

app/src/main/res/values/strings.xml

@@ -584,4 +584,7 @@
   <string name="administrator_controls_fragment_test_activity_label">Administrator Controls Fragment Test Activity</string>
   <string name="revision_navigation_cards_header">Continue Studying</string>
   <string name="state_fragment_hint_bar_forced_announcement_text">Go to the bottom of the screen for a hint.</string>
+  <string name="state_fragment_item_selection_no_items_selected_hint_text">Please select all correct choices.</string>
+  <string name="state_fragment_item_selection_some_items_selected_hint_text">You may select more choices.</string>
+  <string name="state_fragment_item_selection_max_items_selected_hint_text">No more than %s choices may be selected.</string>
 </resources>