Fix part of #6104: Add support for worked examples (GSoC 4.1 PR 2.1)

app/src/main/java/org/oppia/android/app/application/ApplicationModule.kt

@@ -4,11 +4,31 @@ import android.app.Application
 import android.content.Context
 import dagger.Binds
 import dagger.Module
+import dagger.Provides
+import org.oppia.android.app.R
 import org.oppia.android.app.activity.ActivityComponentImpl
+import org.oppia.android.util.parser.html.WorkedExampleAnswerLabelStringId
+import org.oppia.android.util.parser.html.WorkedExampleQuestionLabelStringId
 
 /** Provides core infrastructure needed to support all other dependencies in the app. */
 @Module(subcomponents = [ActivityComponentImpl::class])
 interface ApplicationModule {
   @Binds
   fun provideContext(application: Application): Context
+
+  // Dagger doesn't support mixing binds & provides methods, so string resource ID providers are
+  // defined in a companion module.
+  @Module
+  companion object {
+    @Provides
+    @WorkedExampleQuestionLabelStringId
+    @JvmStatic
+    fun provideWorkedExampleQuestionLabelStringId(): Int =
+      R.string.worked_example_question_label
+
+    @Provides
+    @WorkedExampleAnswerLabelStringId
+    @JvmStatic
+    fun provideWorkedExampleAnswerLabelStringId(): Int = R.string.worked_example_answer_label
+  }
 }

app/src/main/java/org/oppia/android/app/application/BUILD.bazel

@@ -86,6 +86,7 @@ kt_android_library(
     deps = [
         "//app",
         "//domain/src/main/java/org/oppia/android/domain/oppialogger:startup_listener",
+        "//utility/src/main/java/org/oppia/android/util/parser/html:html_parser",
     ],
 )
 

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

@@ -31,6 +31,8 @@
   <string name="concept_card_one_button_text">Concept Card 1</string>
   <string name="concept_card_two_button_text">Concept Card 2</string>
   <string name="revision_card_toolbar_title">Study Guide</string>
+  <string name="worked_example_question_label">Question:</string>
+  <string name="worked_example_answer_label">Answer:</string>
   <string name="unsaved_exploration_dialog_title">Leave to Topic Page?</string>
   <string name="unsaved_exploration_dialog_description">Your progress will not be saved.</string>
   <string name="unsaved_exploration_dialog_leave_button">Leave</string>

app/src/sharedTest/java/org/oppia/android/app/devoptions/featureflags/FeatureFlagsFragmentTest.kt

@@ -166,7 +166,7 @@ class FeatureFlagsFragmentTest {
 
       // Note to developers: if you add/remove a feature flag, please update the expected count.
       onView(withId(R.id.feature_flags_recycler_view))
-        .check(RecyclerViewMatcher.hasItemCount(count = 20))
+        .check(RecyclerViewMatcher.hasItemCount(count = 21))
     }
   }
 

app/src/sharedTest/java/org/oppia/android/app/topic/studyguide/StudyGuideFragmentTest.kt

@@ -196,6 +196,7 @@ class StudyGuideFragmentTest {
   @Before
   fun setUp() {
     TestPlatformParameterModule.forceLoadLessonProtosFromAssets(true)
+    TestPlatformParameterModule.forceEnableWorkedExamples(true)
     ApplicationProvider.getApplicationContext<TestApplication>().inject(this)
     testCoroutineDispatchers.registerIdlingResource()
   }
@@ -274,6 +275,29 @@ class StudyGuideFragmentTest {
     }
   }
 
+  @Test
+  fun testStudyGuide_testTopicSubtopic1_secondSectionShowsOnlyValidWorkedExample() {
+    runWithLaunchedActivityAndAddedFragment(
+      TEST_TOPIC_ID_0,
+      subtopicIndex = 1,
+      subtopicListSize = 1
+    ) {
+      val workedExampleContent = atPositionOnView(
+        recyclerViewId = R.id.study_guide_section_recycler_view,
+        position = 3,
+        targetViewId = R.id.study_guide_section_content_text
+      )
+      onView(workedExampleContent)
+        .check(matches(withText(containsString("Question:\nWhat is one half as a fraction?"))))
+      onView(workedExampleContent)
+        .check(matches(withText(containsString("Answer:\nOne half is 1/2."))))
+      onView(workedExampleContent)
+        .check(matches(not(withText(containsString("This answer should be ignored.")))))
+      onView(workedExampleContent)
+        .check(matches(not(withText(containsString("This question should be ignored.")))))
+    }
+  }
+
   @Test
   fun testStudyGuide_clickConceptCardLinkText_opensConceptCard() {
     runWithLaunchedActivityAndAddedFragment(

config/src/java/org/oppia/android/config/platform/feature_flags.textproto

@@ -98,3 +98,8 @@ feature_flag_definition {
   remote_server_name: "android_enable_study_guides"
   default_is_enabled: false
 }
+feature_flag_definition {
+  id: WORKED_EXAMPLES
+  remote_server_name: "android_enable_worked_examples"
+  default_is_enabled: false
+}

domain/src/main/assets/dev/test_topic_id_0_1.json

@@ -139,7 +139,7 @@
       },
       "content": {
         "content_id": "section_content_3",
-        "html": "<p>This section reviews a related skill: <oppia-noninteractive-skillreview skill_id-with-value=\"&amp;quot;test_skill_id_0&amp;quot;\" text-with-value=\"&amp;quot;test_skill_id_0 concept card&amp;quot;\"></oppia-noninteractive-skillreview>.</p>"
+        "html": "<p>This section reviews a related skill: <oppia-noninteractive-skillreview skill_id-with-value=\"&amp;quot;test_skill_id_0&amp;quot;\" text-with-value=\"&amp;quot;test_skill_id_0 concept card&amp;quot;\"></oppia-noninteractive-skillreview>.</p><p>Worked examples:</p><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;&amp;lt;strong&amp;gt;What is one half as a fraction?&amp;lt;/strong&amp;gt;&amp;quot;\" answer-with-value=\"&amp;quot;&amp;lt;em&amp;gt;One half is 1/2.&amp;lt;/em&amp;gt;&amp;quot;\"></oppia-noninteractive-workedexample><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;&amp;quot;\" answer-with-value=\"&amp;quot;This answer should be ignored.&amp;quot;\"></oppia-noninteractive-workedexample><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;This question should be ignored.&amp;quot;\" answer-with-value=\"&amp;quot;&amp;quot;\"></oppia-noninteractive-workedexample><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;Malformed question\" answer-with-value=\"&amp;quot;This answer should be ignored.&amp;quot;\"></oppia-noninteractive-workedexample>"
       }
     }
   ],

domain/src/main/assets/dev/test_topic_id_0_1.textproto

@@ -171,7 +171,7 @@ sections {
     content_id: "section_heading_2"
   }
   content {
-    html: "<p>This section reviews a related skill: <oppia-noninteractive-skillreview skill_id-with-value=\"&amp;quot;test_skill_id_0&amp;quot;\" text-with-value=\"&amp;quot;test_skill_id_0 concept card&amp;quot;\"></oppia-noninteractive-skillreview>.</p>"
+    html: "<p>This section reviews a related skill: <oppia-noninteractive-skillreview skill_id-with-value=\"&amp;quot;test_skill_id_0&amp;quot;\" text-with-value=\"&amp;quot;test_skill_id_0 concept card&amp;quot;\"></oppia-noninteractive-skillreview>.</p><p>Worked examples:</p><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;&amp;lt;strong&amp;gt;What is one half as a fraction?&amp;lt;/strong&amp;gt;&amp;quot;\" answer-with-value=\"&amp;quot;&amp;lt;em&amp;gt;One half is 1/2.&amp;lt;/em&amp;gt;&amp;quot;\"></oppia-noninteractive-workedexample><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;&amp;quot;\" answer-with-value=\"&amp;quot;This answer should be ignored.&amp;quot;\"></oppia-noninteractive-workedexample><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;This question should be ignored.&amp;quot;\" answer-with-value=\"&amp;quot;&amp;quot;\"></oppia-noninteractive-workedexample><oppia-noninteractive-workedexample question-with-value=\"&amp;quot;Malformed question\" answer-with-value=\"&amp;quot;This answer should be ignored.&amp;quot;\"></oppia-noninteractive-workedexample>"
     content_id: "section_content_3"
   }
 }

domain/src/main/java/org/oppia/android/domain/platformparameter/FeatureFlagBindingModule.kt

@@ -21,6 +21,7 @@ import org.oppia.android.util.platformparameter.EnableSpotlightUi
 import org.oppia.android.util.platformparameter.EnableStudyGuides
 import org.oppia.android.util.platformparameter.EnableTopicInfoTab
 import org.oppia.android.util.platformparameter.EnableTopicPracticeTab
+import org.oppia.android.util.platformparameter.EnableWorkedExamples
 import org.oppia.android.util.platformparameter.LoadImagesFromAssets
 import org.oppia.android.util.platformparameter.LoadLessonProtosFromAssets
 import org.oppia.android.util.platformparameter.PlatformParameterValue
@@ -137,6 +138,11 @@ class FeatureFlagBindingModule {
   fun provideEnableStudyGuides(processState: PlatformParameterProcessState) =
     processState.retrieveFeatureFlag(FeatureFlagId.STUDY_GUIDES)
 
+  @Provides
+  @EnableWorkedExamples
+  fun provideEnableWorkedExamples(processState: PlatformParameterProcessState) =
+    processState.retrieveFeatureFlag(FeatureFlagId.WORKED_EXAMPLES)
+
   private companion object {
     private fun PlatformParameterProcessState.retrieveFeatureFlag(
       featureFlagId: FeatureFlagId

domain/src/main/java/org/oppia/android/domain/platformparameter/FeatureFlagsMapBindingModule.kt

@@ -22,6 +22,7 @@ import org.oppia.android.util.platformparameter.EnableSpotlightUi
 import org.oppia.android.util.platformparameter.EnableStudyGuides
 import org.oppia.android.util.platformparameter.EnableTopicInfoTab
 import org.oppia.android.util.platformparameter.EnableTopicPracticeTab
+import org.oppia.android.util.platformparameter.EnableWorkedExamples
 import org.oppia.android.util.platformparameter.PlatformParameterValue
 
 // TODO(#5835): Remove this module.
@@ -171,4 +172,12 @@ interface FeatureFlagsMapBindingModule {
   fun bindStudyGuides(
     @EnableStudyGuides param: PlatformParameterValue<Boolean>
   ): PlatformParameterValue<Boolean>
+
+  @Binds
+  @IntoMap
+  @FeatureFlags
+  @FeatureFlagIdKey(FeatureFlagId.WORKED_EXAMPLES)
+  fun bindWorkedExamples(
+    @EnableWorkedExamples param: PlatformParameterValue<Boolean>
+  ): PlatformParameterValue<Boolean>
 }

domain/src/test/java/org/oppia/android/domain/oppialogger/analytics/FeatureFlagsLoggerTest.kt

@@ -141,7 +141,7 @@ class FeatureFlagsLoggerTest {
 
   @Test
   fun testLogFeatureFlags_correctNumberOfFeatureFlagsIsLogged() {
-    val expectedFeatureFlagCount = 18
+    val expectedFeatureFlagCount = 19
 
     featureFlagsLogger.logAllFeatureFlags(TEST_SESSION_ID)
     testCoroutineDispatchers.runCurrent()
@@ -171,6 +171,7 @@ class FeatureFlagsLoggerTest {
   @Iteration("edge_to_edge", "index=15", "flagId=EDGE_TO_EDGE")
   @Iteration("lesson_progress_visualization", "index=16", "flagId=LESSON_PROGRESS_VISUALIZATION")
   @Iteration("study_guides", "index=17", "flagId=STUDY_GUIDES")
+  @Iteration("worked_examples", "index=18", "flagId=WORKED_EXAMPLES")
   fun testLogFeatureFlags_allFeatureFlagIdsAreLogged() {
     featureFlagsLogger.logAllFeatureFlags(TEST_SESSION_ID)
 

model/src/main/proto/platform_parameter.proto

@@ -166,6 +166,9 @@ enum FeatureFlagId {
   // Corresponds to a feature that enables study guides, an enhanced version of revision cards that
   // introduces multiple sections with section headers.
   STUDY_GUIDES = 23;
+
+  // Corresponds to whether worked examples should be rendered in rich-text content.
+  WORKED_EXAMPLES = 24;
 }
 
 // Corresponds to a compile-time definition of a platform parameter which is a mechanism by which to

testing/src/main/java/org/oppia/android/testing/platformparameter/TestPlatformParameterModule.kt

@@ -25,6 +25,7 @@ import org.oppia.android.app.model.FeatureFlagId.SPOTLIGHT_UI
 import org.oppia.android.app.model.FeatureFlagId.STUDY_GUIDES
 import org.oppia.android.app.model.FeatureFlagId.TOPIC_INFO_TAB
 import org.oppia.android.app.model.FeatureFlagId.TOPIC_PRACTICE_TAB
+import org.oppia.android.app.model.FeatureFlagId.WORKED_EXAMPLES
 import org.oppia.android.domain.platformparameter.FeatureFlagBindingModule
 import org.oppia.android.domain.platformparameter.FeatureFlagsMapBindingModule
 import org.oppia.android.domain.platformparameter.PlatformParameterBindingModule
@@ -175,6 +176,10 @@ class TestPlatformParameterModule {
       TestPlatformParameterConfigRetriever.setFlagOverride(STUDY_GUIDES, value)
     }
 
+    fun forceEnableWorkedExamples(value: Boolean) {
+      TestPlatformParameterConfigRetriever.setFlagOverride(WORKED_EXAMPLES, value)
+    }
+
     fun reset() {
       TestPlatformParameterConfigRetriever.reset()
     }

testing/src/main/java/org/oppia/android/testing/topic/StudyGuideTestHelper.kt

@@ -45,7 +45,20 @@ class StudyGuideTestHelper @Inject constructor() {
         "<oppia-noninteractive-skillreview " +
         "skill_id-with-value=\"&amp;quot;test_skill_id_0&amp;quot;\" " +
         "text-with-value=\"&amp;quot;test_skill_id_0 concept card&amp;quot;\">" +
-        "</oppia-noninteractive-skillreview>.</p>"
+        "</oppia-noninteractive-skillreview>.</p><p>Worked examples:</p>" +
+        "<oppia-noninteractive-workedexample question-with-value=\"&amp;quot;" +
+        "&amp;lt;strong&amp;gt;What is one half as a fraction?&amp;lt;/strong&amp;gt;" +
+        "&amp;quot;\" answer-with-value=\"&amp;quot;&amp;lt;em&amp;gt;One half is 1/2." +
+        "&amp;lt;/em&amp;gt;&amp;quot;\"></oppia-noninteractive-workedexample>" +
+        "<oppia-noninteractive-workedexample question-with-value=\"&amp;quot;&amp;quot;\" " +
+        "answer-with-value=\"&amp;quot;This answer should be ignored.&amp;quot;\">" +
+        "</oppia-noninteractive-workedexample><oppia-noninteractive-workedexample " +
+        "question-with-value=\"&amp;quot;This question should be ignored.&amp;quot;\" " +
+        "answer-with-value=\"&amp;quot;&amp;quot;\"></oppia-noninteractive-workedexample>" +
+        "<oppia-noninteractive-workedexample " +
+        "question-with-value=\"&amp;quot;Malformed question\" " +
+        "answer-with-value=\"&amp;quot;This answer should be ignored.&amp;quot;\">" +
+        "</oppia-noninteractive-workedexample>"
     )
   )
 

utility/src/main/java/org/oppia/android/util/parser/html/BUILD.bazel

@@ -16,6 +16,7 @@ kt_android_library(
         ":tag_handlers",
         "//third_party:androidx_core_core-ktx",
         "//third_party:javax_inject_javax_inject",
+        "//utility:resources",
         "//utility/src/main/java/org/oppia/android/util/locale:oppia_locale",
         "//utility/src/main/java/org/oppia/android/util/logging:console_logger",
         "//utility/src/main/java/org/oppia/android/util/parser/image:url_image_parser",
@@ -30,6 +31,7 @@ kt_android_library(
         "LiTagHandler.kt",
         "MathTagHandler.kt",
         "PolicyPageTagHandler.kt",
+        "WorkedExampleTagHandler.kt",
     ],
     visibility = ["//utility:__subpackages__"],
     deps = [

utility/src/main/java/org/oppia/android/util/parser/html/ConceptCardTagHandler.kt

@@ -30,7 +30,8 @@ class ConceptCardTagHandler(
     openIndex: Int,
     closeIndex: Int,
     output: Editable,
-    imageRetriever: CustomHtmlContentHandler.ImageRetriever?
+    imageRetriever: CustomHtmlContentHandler.ImageRetriever?,
+    customHtmlParser: CustomHtmlContentHandler.CustomHtmlParser
   ) {
     // Replace the custom tag with a clickable piece of text based on the tag's customizations.
     val skillId = attributes.getJsonStringValue(CUSTOM_CONCEPT_CARD_SKILL_ID)
@@ -58,7 +59,10 @@ class ConceptCardTagHandler(
     fun onConceptCardLinkClicked(view: View, skillId: String)
   }
 
-  override fun getContentDescription(attributes: Attributes): String? {
+  override fun getContentDescription(
+    attributes: Attributes,
+    customHtmlParser: CustomHtmlContentHandler.CustomHtmlParser
+  ): String? {
     val skillId = attributes.getJsonStringValue(CUSTOM_CONCEPT_CARD_SKILL_ID)
     return if (!skillId.isNullOrBlank()) {
       "$skillId concept card"