Fixes #3169: Item selection interaction text change and checkboxes sh…

…ould be disabled on selection (#4777)

<!-- READ ME FIRST: Please fill in the explanation section below and
check off every point from the Essential Checklist! -->
## Explanation
Fixes #3169
Fixes #3624

This PR is doing 2 things - 

1. It's updating the textView based on the selection of checkboxes by
the user, If the user has not selected any checkbox then the Text will
be `Please select all correct choices.`, If the user has selected less
than maxSelection then the text will be `You may select more choices.`
and if the user has selected maxSelection then the text will be `No more
than $maxSelection choices may be selected.`

2. If the user has selected maximum checkboxes that can be selected,
then the non selected checkboxes will be disbaled, and if the user
unselects the checkbox or checkboxes, then all checkboxes will get
enabled.

This is the link to the repository for the comparison of the
StateFragmentTest.kt, to show that the same tests are failing on both
branches(i.e. my feature branch and my develop branch)

https://github.com/Akshatkamboj14/Test-Comparison-For-StateFragmentTest.kt-oppia-android

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- Explain what your PR does. If this PR fixes an existing bug, please
include
- "Fixes #bugnum:" in the explanation so that GitHub can auto-close the
issue
  - when this PR is merged.
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## Essential Checklist
<!-- Please tick the relevant boxes by putting an "x" in them. -->
- [x] The PR title and explanation each start with "Fix #bugnum: " (If
this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

## For UI-specific PRs only
<!-- Delete these section if this PR does not include UI-related
changes. -->
If your PR includes UI-related changes, then:
- Add screenshots for portrait/landscape for both a tablet & phone of
the before & after UI changes
- For the screenshots above, include both English and pseudo-localized
(RTL) screenshots (see [RTL
guide](https://github.com/oppia/oppia-android/wiki/RTL-Guidelines))
- Add a video showing the full UX flow with a screen reader enabled (see
[accessibility
guide](https://github.com/oppia/oppia-android/wiki/Accessibility-(A11y)-Guide))
- Add a screenshot demonstrating that you ran affected Espresso tests
locally & that they're passing


[issue.webm](https://user-images.githubusercontent.com/92685493/221786503-45d2c027-bedd-4cfb-92ce-3e351e81c34b.webm)

---------

Co-authored-by: Ben Henning <[email protected]>

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>