Fix #5915: Improve TalkBack content description for concept card links (#6033)

## Explanation
Fix #5915: Improve TalkBack reading for concept card links

This PR updates the accessibility content description for the
`<oppia-noninteractive-skillreview>` custom HTML tag.

Earlier, TalkBack skipped the concept card link values.
Now, TalkBack consistently reads:

“<skill_id> concept card”

This improves the screen-reader experience in:

- Hint section
- Solution section
- Flashback solution section

## What this fixes

TalkBack was not reading concept-card links correctly because the custom
HTML tag did not provide a clear accessibility description.
This PR fixes the issue and makes the content accessible for learners
using screen readers.

## What was changed

Updated `ConceptCardTagHandler.getContentDescription()` 
 → Now returns a clean, consistent description using only the`skill_id.`

Updated `SolutionViewModel` 
→ Now uses `CustomHtmlContentHandler.getContentDescription() `together
with `ConceptCardTagHandler` to ensure correct accessibility parsing
across hint and solution screens.

Additional note

This PR also includes an auto-format update to
`scripts/assets/kdoc_validity_exemptions.textproto`
generated automatically by ktlint. No functional changes were made.

## Testing done

Tested TalkBack behavior in all places where concept-card links appear:

- Hint section
- Solution section
- Flashback mode

TalkBack now reads the concept card link:

- Exactly once
- In the correct format
- With the correct text

## Ready for review

Screen recording demonstrating TalkBack reading concept card links
correctly in all 3 places:
🔗https://drive.google.com/file/d/1y6pqNhccfw5rjqeOtr_VNsF78jvSTvPN/view?usp=sharing


## 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-o-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

Author: CodeWithSangeeta

app/src/main/java/org/oppia/android/app/hintsandsolution/SolutionViewModel.kt

@@ -1,5 +1,6 @@
 package org.oppia.android.app.hintsandsolution
 
+import android.view.View
 import androidx.databinding.ObservableBoolean
 import org.oppia.android.app.model.Interaction
 import org.oppia.android.app.model.InteractionObject
@@ -29,6 +30,7 @@ import org.oppia.android.app.translation.AppLanguageResourceHandler
 import org.oppia.android.app.utility.math.MathExpressionAccessibilityUtil
 import org.oppia.android.app.utility.toAccessibleAnswerString
 import org.oppia.android.app.view.models.R
+import org.oppia.android.util.logging.ConsoleLogger
 import org.oppia.android.util.math.MathExpressionParser.Companion.ErrorCheckingMode.REQUIRED_ONLY
 import org.oppia.android.util.math.MathExpressionParser.Companion.MathParsingResult
 import org.oppia.android.util.math.MathExpressionParser.Companion.parseAlgebraicEquation
@@ -38,6 +40,8 @@ import org.oppia.android.util.math.isApproximatelyEqualTo
 import org.oppia.android.util.math.toAnswerString
 import org.oppia.android.util.math.toPlainString
 import org.oppia.android.util.math.toRawLatex
+import org.oppia.android.util.parser.html.CUSTOM_CONCEPT_CARD_TAG
+import org.oppia.android.util.parser.html.ConceptCardTagHandler
 import org.oppia.android.util.parser.html.CustomHtmlContentHandler
 import javax.inject.Inject
 
@@ -61,18 +65,24 @@ class SolutionViewModel private constructor(
   private val mathExpressionAccessibilityUtil: MathExpressionAccessibilityUtil,
   val explorationId: String,
   val isFlashback: Boolean,
-  val solutionBoxStrokeWidth: Int
+  val solutionBoxStrokeWidth: Int,
+  private val consoleLogger: ConsoleLogger
 ) {
-  /**
-   * A screenreader-friendly version of [solutionSummary] that should be used for readout, in place
-   * of the original summary.
-   */
+  /** Lazily computes the accessibility content description for the solution summary HTML content. */
   val solutionSummaryContentDescription by lazy {
-    CustomHtmlContentHandler.fromHtml(
+    CustomHtmlContentHandler.getContentDescription(
       solutionSummary,
-      imageRetriever = null,
-      customTagHandlers = mapOf()
-    ).toString()
+      customTagHandlers = mapOf(
+        CUSTOM_CONCEPT_CARD_TAG to ConceptCardTagHandler(
+          listener = object : ConceptCardTagHandler.ConceptCardLinkClickListener {
+            override fun onConceptCardLinkClicked(view: View, skillId: String) {
+              // No action for TalkBack readout
+            }
+          },
+          consoleLogger = consoleLogger
+        )
+      )
+    )
   }
 
   /** A displayable HTML representation of the correct answer presented by this model's solution. */
@@ -239,7 +249,8 @@ class SolutionViewModel private constructor(
   /** Application-injectable factory to create [SolutionViewModel]s (see [create]). */
   class Factory @Inject constructor(
     private val appLanguageResourceHandler: AppLanguageResourceHandler,
-    private val mathExpressionAccessibilityUtil: MathExpressionAccessibilityUtil
+    private val mathExpressionAccessibilityUtil: MathExpressionAccessibilityUtil,
+    private val consoleLogger: ConsoleLogger
   ) {
     /**
      * Returns a new [SolutionViewModel] with the specified summary HTML text, correct answer,
@@ -269,7 +280,8 @@ class SolutionViewModel private constructor(
         mathExpressionAccessibilityUtil,
         explorationId,
         isFlashback,
-        solutionBoxStrokeWidth
+        solutionBoxStrokeWidth,
+        consoleLogger
       )
     }
 

app/src/sharedTest/java/org/oppia/android/app/player/exploration/ExplorationActivityTest.kt

@@ -1682,8 +1682,8 @@ class ExplorationActivityTest {
         .check(
           matches(
             withContentDescription(
-              "Remember that two halves, when added together, make one whole." +
-                "\nClick on this test_skill_id_1 concept card."
+              "Remember that two halves, when added together, make one whole.\n" +
+                "Click on this test_skill_id_1 concept card."
             )
           )
         )

app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt

@@ -5600,7 +5600,7 @@ class StateFragmentTest {
       onView(withId(R.id.solution_summary_label)).check(matches(withText("Explanation:")))
 
       val expectedSolutionSummary = "Half of something has one part in the numerator for" +
-        " every two parts in the denominator."
+        " every two parts in the denominator.\n\n"
       onView(withId(R.id.solution_summary))
         .check(matches(withText(containsString(expectedSolutionSummary))))
 
@@ -5652,7 +5652,7 @@ class StateFragmentTest {
       onView(withId(R.id.solution_summary_label)).check(matches(withText("Explanation:")))
 
       val expectedSolutionSummary = "Half of something has one part in the numerator for" +
-        " every two parts in the denominator."
+        " every two parts in the denominator.\n\n"
       onView(withId(R.id.solution_summary))
         .check(matches(withText(containsString(expectedSolutionSummary))))
 

app/src/test/java/org/oppia/android/app/player/state/StateFragmentLocalTest.kt

@@ -1317,8 +1317,8 @@ class StateFragmentLocalTest {
       onView(withId(R.id.solution_summary)).check(
         matches(
           withContentDescription(
-            "Start by dividing the cake into equal parts:\n\nThree of " +
-              "the four equal parts are red. So, the answer is 3/4.\n\n"
+            "Start by dividing the cake into equal parts:" +
+              "\nThree of the four equal parts are red. So, the answer is 3/4."
           )
         )
       )

scripts/assets/kdoc_validity_exemptions.textproto

@@ -299,7 +299,6 @@ exempted_file_path: "testing/src/main/java/org/oppia/android/testing/threading/T
 exempted_file_path: "testing/src/main/java/org/oppia/android/testing/threading/TestCoroutineDispatchersRobolectricImpl.kt"
 exempted_file_path: "testing/src/test/java/org/oppia/android/testing/threading/TestCoroutineDispatcherTestBase.kt"
 exempted_file_path: "utility/src/main/java/org/oppia/android/util/logging/LogLevel.kt"
-exempted_file_path: "utility/src/main/java/org/oppia/android/util/parser/html/ConceptCardTagHandler.kt"
 exempted_file_path: "utility/src/main/java/org/oppia/android/util/parser/html/MathTagHandler.kt"
 exempted_file_path: "utility/src/main/java/org/oppia/android/util/parser/image/UrlImageParser.kt"
 exempted_file_path: "utility/src/main/java/org/oppia/android/util/parser/svg/ScalableVectorGraphic.kt"

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

@@ -11,10 +11,16 @@ import javax.inject.Inject
 
 /** The custom tag corresponding to [ConceptCardTagHandler]. */
 const val CUSTOM_CONCEPT_CARD_TAG = "oppia-noninteractive-skillreview"
+/** The attribute key used to extract the concept card skill ID from the custom tag. */
 const val CUSTOM_CONCEPT_CARD_SKILL_ID = "skill_id-with-value"
+/** The attribute key used to extract the visible concept card text from the custom tag. */
 const val CUSTOM_CONCEPT_CARD_TEXT_VALUE = "text-with-value"
 
 // https://mohammedlakkadshaw.com/blog/handling-custom-tags-in-android-using-html-taghandler.html/
+/**
+ * A custom tag handler responsible for converting concept card custom tags into clickable spans and
+ * generating the appropriate accessibility content description.
+ */
 class ConceptCardTagHandler(
   private val listener: ConceptCardLinkClickListener,
   private val consoleLogger: ConsoleLogger
@@ -53,9 +59,9 @@ class ConceptCardTagHandler(
   }
 
   override fun getContentDescription(attributes: Attributes): String? {
-    val text = attributes.getJsonStringValue(CUSTOM_CONCEPT_CARD_TEXT_VALUE)
-    return if (!text.isNullOrBlank()) {
-      text
+    val skillId = attributes.getJsonStringValue(CUSTOM_CONCEPT_CARD_SKILL_ID)
+    return if (!skillId.isNullOrBlank()) {
+      "$skillId concept card"
     } else ""
   }
 

utility/src/test/java/org/oppia/android/util/parser/html/ConceptCardTagHandlerTest.kt

@@ -124,7 +124,7 @@ class ConceptCardTagHandlerTest {
         html = CONCEPT_CARD_LINK_MARKUP_1,
         customTagHandlers = tagHandlersWithConceptCardSupport
       )
-    assertThat(contentDescription).isEqualTo("refresher lesson")
+    assertThat(contentDescription).isEqualTo("skill_id_1 concept card")
   }
 
   @Test

utility/src/test/java/org/oppia/android/util/parser/html/HtmlParserTest.kt

@@ -895,7 +895,7 @@ class HtmlParserTest {
         textView.text = htmlResult
 
         assertThat(textView.contentDescription.toString()).isEqualTo(
-          "Visit refresher lesson to learn more."
+          "Visit skill_id_1 concept card to learn more."
         )
       }
     }