Fix #4648: Fix topic lesson differentiation between locked, completed…

… and in-progress lessons (#4958)

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## Explanation
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Fix #4648: When this PR is merged, it will fix the issue of locked,
completed and in progress lessons not being differentiated by Talkback.

## Essential Checklist
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app/src/main/java/org/oppia/android/app/topic/lessons/ChapterSummaryViewModel.kt

@@ -11,6 +11,7 @@ class ChapterSummaryViewModel(
   val chapterPlayState: ChapterPlayState,
   val explorationId: String,
   val chapterTitle: String,
+  val previousChapterTitle: String?,
   val storyId: String,
   private val index: Int,
   private val chapterSummarySelector: ChapterSummarySelector,
@@ -23,14 +24,28 @@ class ChapterSummaryViewModel(
   }
 
   fun computeChapterPlayStateIconContentDescription(): String {
-    return if (chapterPlayState == ChapterPlayState.COMPLETED) {
-      resourceHandler.getStringInLocaleWithWrapping(
-        R.string.chapter_completed, (index + 1).toString(), chapterTitle
-      )
-    } else {
-      resourceHandler.getStringInLocaleWithWrapping(
-        R.string.chapter_in_progress, (index + 1).toString(), chapterTitle
-      )
+    return when (chapterPlayState) {
+      ChapterPlayState.COMPLETED -> {
+        resourceHandler.getStringInLocaleWithWrapping(
+          R.string.chapter_completed, (index + 1).toString(), chapterTitle
+        )
+      }
+      ChapterPlayState.NOT_PLAYABLE_MISSING_PREREQUISITES -> {
+        if (previousChapterTitle != null) {
+          resourceHandler.getStringInLocaleWithWrapping(
+            R.string.chapter_prerequisite_title_label, index.toString(), previousChapterTitle
+          )
+        } else {
+          resourceHandler.getStringInLocaleWithWrapping(
+            R.string.chapter_prerequisite_title_label_without_chapter_title
+          )
+        }
+      }
+      else -> {
+        resourceHandler.getStringInLocaleWithWrapping(
+          R.string.chapter_in_progress, (index + 1).toString(), chapterTitle
+        )
+      }
     }
   }
 

app/src/main/java/org/oppia/android/app/topic/lessons/StorySummaryViewModel.kt

@@ -77,6 +77,12 @@ class StorySummaryViewModel(
           ephemeralChapterSummary.chapterSummary.title,
           ephemeralChapterSummary.writtenTranslationContext
         ),
+        previousChapterTitle = if (index > 0) {
+          translationController.extractString(
+            ephemeralStorySummary.chaptersList[index - 1].chapterSummary.title,
+            ephemeralStorySummary.chaptersList[index - 1].writtenTranslationContext
+          )
+        } else null,
         storyId = storySummary.storyId,
         index = index,
         chapterSummarySelector = chapterSummarySelector,

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

@@ -37,6 +37,7 @@
       android:text="@{viewModel.computePlayChapterIndexText()}"
       android:textColor="@color/component_color_shared_secondary_4_text_color"
       android:textSize="20sp"
+      android:contentDescription="@{viewModel.computeChapterPlayStateIconContentDescription()}"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
 
@@ -48,7 +49,7 @@
       android:background="@color/component_color_lessons_tab_activity_lessons_completed_chapter_name_background_color"
       android:fontFamily="sans-serif"
       android:gravity="center|start"
-      android:importantForAccessibility="yes"
+      android:importantForAccessibility="no"
       android:minHeight="48dp"
       android:paddingStart="12dp"
       android:paddingEnd="12dp"

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

@@ -91,6 +91,7 @@
   <string name="chapter_completed">Chapter %s with title %s is completed</string>
   <string name="chapter_in_progress">Chapter %s with title %s is in progress</string>
   <string name="chapter_prerequisite_title_label">Complete Chapter %s: %s to unlock this chapter.</string>
+  <string name="chapter_prerequisite_title_label_without_chapter_title">Complete the previous chapter to unlock this chapter.</string>
   <string name="text_input_default_content_description">Enter text.</string>
   <string name="fractions_default_hint_text">Enter a fraction in the form x/x, or a mixed number in the form x x/x.</string>
   <string name="fractions_default_hint_text_no_integer">Enter a fraction in the form x/x.</string>

app/src/sharedTest/java/org/oppia/android/app/topic/lessons/TopicLessonsFragmentTest.kt

@@ -17,6 +17,7 @@ import androidx.test.espresso.intent.Intents
 import androidx.test.espresso.intent.Intents.intended
 import androidx.test.espresso.intent.matcher.IntentMatchers.hasComponent
 import androidx.test.espresso.intent.matcher.IntentMatchers.hasExtra
+import androidx.test.espresso.matcher.ViewMatchers.hasContentDescription
 import androidx.test.espresso.matcher.ViewMatchers.hasDescendant
 import androidx.test.espresso.matcher.ViewMatchers.isClickable
 import androidx.test.espresso.matcher.ViewMatchers.isDescendantOfA
@@ -348,6 +349,29 @@ class TopicLessonsFragmentTest {
     }
   }
 
+  @Test
+  fun testLessonsPlayFragment_loadRatiosTopic_chapterIsLocked_contentDescriptionIsCorrect() {
+    launch<TopicActivity>(createTopicActivityIntent(internalProfileId, RATIOS_TOPIC_ID)).use {
+      clickLessonTab()
+      clickStoryItem(position = 1, targetViewId = R.id.chapter_list_drop_down_icon)
+      onView(
+        atPositionOnView(
+          recyclerViewId = R.id.chapter_recycler_view,
+          position = 1,
+          targetViewId = R.id.chapter_play_state_icon
+        )
+      ).check(matches(isDisplayed()))
+        .check(matches(hasContentDescription()))
+        .check(
+          matches(
+            withContentDescription(
+              "Complete Chapter 1: What is a Ratio? to unlock this chapter."
+            )
+          )
+        )
+    }
+  }
+
   @Test
   fun testLessonsPlayFragment_loadRatiosTopic_chapterCompletedIsCorrectlyDisplayed() {
     storyProgressTestHelper.markCompletedRatiosStory0Exp0(
@@ -367,6 +391,33 @@ class TopicLessonsFragmentTest {
     }
   }
 
+  @Test
+  fun testLessonsPlayFragment_loadRatiosTopic_chapterCompleted_contentDescriptionIsCorrect() {
+    storyProgressTestHelper.markCompletedRatiosStory0Exp0(
+      profileId,
+      timestampOlderThanOneWeek = false
+    )
+    launch<TopicActivity>(createTopicActivityIntent(internalProfileId, RATIOS_TOPIC_ID)).use {
+      clickLessonTab()
+      clickStoryItem(position = 1, targetViewId = R.id.chapter_list_drop_down_icon)
+      onView(
+        atPositionOnView(
+          recyclerViewId = R.id.chapter_recycler_view,
+          position = 0,
+          targetViewId = R.id.chapter_index
+        )
+      ).check(matches(isDisplayed()))
+        .check(matches(hasContentDescription()))
+        .check(
+          matches(
+            withContentDescription(
+              "Chapter 1 with title What is a Ratio? is completed"
+            )
+          )
+        )
+    }
+  }
+
   @Test
   fun testLessonsPlayFragment_loadRatiosTopic_chapterInProgressIsCorrectlyDisplayed() {
     fakeOppiaClock.setFakeTimeMode(FakeOppiaClock.FakeTimeMode.MODE_UPTIME_MILLIS)
@@ -387,6 +438,34 @@ class TopicLessonsFragmentTest {
     }
   }
 
+  @Test
+  fun testLessonsPlayFragment_loadRatiosTopic_chapterInProgress_contentDescriptionIsCorrect() {
+    fakeOppiaClock.setFakeTimeMode(FakeOppiaClock.FakeTimeMode.MODE_UPTIME_MILLIS)
+    storyProgressTestHelper.markInProgressSavedRatiosStory0Exp0(
+      profileId,
+      timestampOlderThanOneWeek = false
+    )
+    launch<TopicActivity>(createTopicActivityIntent(internalProfileId, RATIOS_TOPIC_ID)).use {
+      clickLessonTab()
+      clickStoryItem(position = 1, targetViewId = R.id.chapter_list_drop_down_icon)
+      onView(
+        atPositionOnView(
+          recyclerViewId = R.id.chapter_recycler_view,
+          position = 0,
+          targetViewId = R.id.chapter_play_state_icon
+        )
+      ).check(matches(isDisplayed()))
+        .check(matches(hasContentDescription()))
+        .check(
+          matches(
+            withContentDescription(
+              "Chapter 1 with title What is a Ratio? is in progress"
+            )
+          )
+        )
+    }
+  }
+
   @Test
   fun testLessonsPlayFragment_loadRatiosTopic_configChange_chapterLockedIsCorrectlyDisplayed() {
     launch<TopicActivity>(createTopicActivityIntent(internalProfileId, RATIOS_TOPIC_ID)).use {