fix part of #4839 Hint dialog can show up during answer input and interrupt the user's experience

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

@@ -33,6 +33,7 @@ import org.oppia.android.app.player.audio.AudioUiManager
 import org.oppia.android.app.player.state.ConfettiConfig.LARGE_CONFETTI_BURST
 import org.oppia.android.app.player.state.ConfettiConfig.MEDIUM_CONFETTI_BURST
 import org.oppia.android.app.player.state.ConfettiConfig.MINI_CONFETTI_BURST
+import org.oppia.android.app.player.state.itemviewmodel.StateItemViewModel
 import org.oppia.android.app.player.state.listener.RouteToHintsAndSolutionListener
 import org.oppia.android.app.player.stopplaying.StopStatePlayingSessionWithSavedProgressListener
 import org.oppia.android.app.survey.SurveyWelcomeDialogFragment
@@ -258,7 +259,9 @@ class StateFragmentPresenter @Inject constructor(
       )
       .addHintsAndSolutionsSupport()
       .addAudioVoiceoverSupport(
-        explorationId, viewModel.currentStateName, viewModel.isAudioBarVisible,
+        explorationId,
+        viewModel.currentStateName,
+        viewModel.isAudioBarVisible,
         this::getAudioUiManager
       )
       .addConceptCardSupport()
@@ -304,6 +307,14 @@ class StateFragmentPresenter @Inject constructor(
     }
   }
 
+  private fun areListsTheSame(l: List<StateItemViewModel>, r: List<StateItemViewModel>): Boolean {
+    if (l.size != r.size) {
+      return false
+    }
+
+    return l.zip(r).all { (x, y) -> x.areContentsTheSame(y) }
+  }
+
   private fun processEphemeralState(ephemeralState: EphemeralState) {
     explorationCheckpointState = ephemeralState.checkpointState
     val shouldSplit = splitScreenManager.shouldSplitScreen(ephemeralState.state.interaction.id)
@@ -329,10 +340,14 @@ class StateFragmentPresenter @Inject constructor(
       shouldSplit
     )
 
-    viewModel.itemList.clear()
-    viewModel.itemList += dataPair.first
-    viewModel.rightItemList.clear()
-    viewModel.rightItemList += dataPair.second
+    if (!areListsTheSame(viewModel.itemList, dataPair.first)) {
+      viewModel.itemList.clear()
+      viewModel.itemList += dataPair.first
+    }
+    if (!areListsTheSame(viewModel.rightItemList, dataPair.second)) {
+      viewModel.rightItemList.clear()
+      viewModel.rightItemList += dataPair.second
+    }
 
     if (isInNewState) {
       (binding.stateRecyclerView.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(
@@ -400,7 +415,9 @@ class StateFragmentPresenter @Inject constructor(
     return when (ephemeralStateResult) {
       is AsyncResult.Failure -> {
         oppiaLogger.e(
-          "StateFragment", "Failed to retrieve answer outcome", ephemeralStateResult.error
+          "StateFragment",
+          "Failed to retrieve answer outcome",
+          ephemeralStateResult.error
         )
         AnswerOutcome.getDefaultInstance()
       }
@@ -465,7 +482,6 @@ class StateFragmentPresenter @Inject constructor(
   }
 
   private fun showHintsAndSolutions(helpIndex: HelpIndex, isCurrentStatePendingState: Boolean) {
-
     if (!isCurrentStatePendingState) {
       // If current state is not the pending top state, hide the hint bulb.
       setHintOpenedAndUnRevealed(false)
@@ -499,7 +515,6 @@ class StateFragmentPresenter @Inject constructor(
   private fun setHintOpenedAndUnRevealed(isHintUnrevealed: Boolean) {
     viewModel.setHintOpenedAndUnRevealedVisibility(isHintUnrevealed)
     if (isHintUnrevealed) {
-
       val hintBulbAnimation = AnimationUtils.loadAnimation(
         context,
         R.anim.hint_bulb_animation

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

@@ -7,4 +7,15 @@ class ContentViewModel(
   val hasConversationView: Boolean,
   val isSplitView: Boolean,
   val supportsConceptCards: Boolean
-) : StateItemViewModel(ViewType.CONTENT)
+) : StateItemViewModel(ViewType.CONTENT) {
+  override fun areContentsTheSame(other: StateItemViewModel): Boolean {
+    if (this === other) return true
+    if (other !is ContentViewModel) return false
+
+    return htmlContent == other.htmlContent &&
+      gcsEntityId == other.gcsEntityId &&
+      hasConversationView == other.hasConversationView &&
+      isSplitView == other.isSplitView &&
+      supportsConceptCards == other.supportsConceptCards
+  }
+}

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

@@ -56,6 +56,18 @@ class FractionInteractionViewModel private constructor(
     )
   }
 
+  override fun areContentsTheSame(other: StateItemViewModel): Boolean {
+    if (this === other) return true
+    if (other !is FractionInteractionViewModel) return false
+
+    return (
+      hasConversationView == other.hasConversationView &&
+        isSplitView == other.isSplitView &&
+        pendingAnswerError == other.pendingAnswerError &&
+        hintText == other.hintText
+      )
+  }
+
   override fun getPendingAnswer(): UserAnswer = UserAnswer.newBuilder().apply {
     if (answerText.isNotEmpty()) {
       val answerTextString = answerText.toString()

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

@@ -61,4 +61,8 @@ abstract class StateItemViewModel(val viewType: ViewType) : ObservableViewModel(
       timeToStartNoticeAnimationMs: Long?
     ): StateItemViewModel
   }
+
+  open fun areContentsTheSame(other: StateItemViewModel): Boolean {
+    return false
+  }
 }

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

@@ -12,4 +12,16 @@ class SubmitButtonViewModel(
   val previousNavigationButtonListener: PreviousNavigationButtonListener,
   val submitNavigationButtonListener: SubmitNavigationButtonListener,
   val isSplitView: Boolean
-) : StateItemViewModel(ViewType.SUBMIT_ANSWER_BUTTON)
+) : StateItemViewModel(ViewType.SUBMIT_ANSWER_BUTTON) {
+  override fun areContentsTheSame(other: StateItemViewModel): Boolean {
+    if (this === other) return true
+    if (other !is SubmitButtonViewModel) return false
+
+    return (
+      canSubmitAnswer.get() == other.canSubmitAnswer.get() &&
+        hasConversationView == other.hasConversationView &&
+        hasPreviousButton == other.hasPreviousButton &&
+        isSplitView == other.isSplitView
+      )
+  }
+}