Hide items if all items they are depending on have also been hidden. (#…

…1790)

* Disable all question items in a dependent chain when top item is disabled

* Reverted the default layout

* Caching answers for disabled items incase they are enabled again before submitting

* Updated review comments

* Review comments: Refactored code and addded testcase to check cache restoration

datacapture/src/main/java/com/google/android/fhir/datacapture/QuestionnaireViewModel.kt

@@ -47,6 +47,8 @@ import org.hl7.fhir.r4.model.Coding
 import org.hl7.fhir.r4.model.Expression
 import org.hl7.fhir.r4.model.Questionnaire
 import org.hl7.fhir.r4.model.QuestionnaireResponse
+import org.hl7.fhir.r4.model.QuestionnaireResponse.QuestionnaireResponseItemAnswerComponent
+import org.hl7.fhir.r4.model.QuestionnaireResponse.QuestionnaireResponseItemComponent
 import org.hl7.fhir.r4.model.ResourceType
 import org.hl7.fhir.r4.model.ValueSet
 import timber.log.Timber
@@ -61,7 +63,6 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
 
  /** The current questionnaire as questions are being answered. */
  internal val questionnaire: Questionnaire
- private lateinit var currentPageItems: List<QuestionnaireAdapterItem>
 
  init {
  questionnaire =
@@ -94,15 +95,6 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  /** The current questionnaire response as questions are being answered. */
  private val questionnaireResponse: QuestionnaireResponse
 
- /**
- * True if the user has tapped the next/previous pagination buttons on the current page. This is
- * needed to avoid spewing validation errors before any questions are answered.
- */
- private var isPaginationButtonPressed = false
-
- /** Forces response validation each time [getQuestionnaireAdapterItems] is called. */
- private var hasPressedSubmitButton = false
-
  init {
  when {
  state.contains(QuestionnaireFragment.EXTRA_QUESTIONNAIRE_RESPONSE_JSON_URI) -> {
@@ -192,13 +184,33 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  private val isInReviewModeFlow = MutableStateFlow(shouldShowReviewPageFirst)
 
  /**
- * Contains [QuestionnaireResponse.QuestionnaireResponseItemComponent]s that have been modified by
- * the user. [QuestionnaireResponse.QuestionnaireResponseItemComponent]s that have not been
- * modified by the user will not be validated. This is to avoid spamming the user with a sea of
- * validation errors when the questionnaire is loaded initially.
+ * Contains [QuestionnaireResponseItemComponent]s that have been modified by the user.
+ * [QuestionnaireResponseItemComponent]s that have not been modified by the user will not be
+ * validated. This is to avoid spamming the user with a sea of validation errors when the
+ * questionnaire is loaded initially.
  */
  private val modifiedQuestionnaireResponseItemSet =
- mutableSetOf<QuestionnaireResponse.QuestionnaireResponseItemComponent>()
+ mutableSetOf<QuestionnaireResponseItemComponent>()
+
+ private lateinit var currentPageItems: List<QuestionnaireAdapterItem>
+
+ /**
+ * True if the user has tapped the next/previous pagination buttons on the current page. This is
+ * needed to avoid spewing validation errors before any questions are answered.
+ */
+ private var isPaginationButtonPressed = false
+
+ /** Forces response validation each time [getQuestionnaireAdapterItems] is called. */
+ private var hasPressedSubmitButton = false
+
+ /**
+ * Map of [QuestionnaireResponseItemAnswerComponent] for
+ * [Questionnaire.QuestionnaireItemComponent]s that are disabled now. The answers will be used to
+ * pre-populate the [QuestionnaireResponseItemComponent] once the item is enabled again.
+ */
+ private val responseItemToAnswersMapForDisabledQuestionnaireItem =
+ mutableMapOf<
+ QuestionnaireResponseItemComponent, List<QuestionnaireResponseItemAnswerComponent>>()
 
  /**
  * Callback function to update the view model after the answer(s) to a question have been changed.
@@ -211,16 +223,15 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  *
  * This callback function has 3 params:
  * - the reference to the [Questionnaire.QuestionnaireItemComponent] in the [Questionnaire]
- * - the reference to the [QuestionnaireResponse.QuestionnaireResponseItemComponent] in the
- * [QuestionnaireResponse]
- * - a [List] of [QuestionnaireResponse.QuestionnaireResponseItemAnswerComponent] which are the
- * new answers to the question.
+ * - the reference to the [QuestionnaireResponseItemComponent] in the [QuestionnaireResponse]
+ * - a [List] of [QuestionnaireResponseItemAnswerComponent] which are the new answers to the
+ * question.
  */
  private val answersChangedCallback:
  (
  Questionnaire.QuestionnaireItemComponent,
- QuestionnaireResponse.QuestionnaireResponseItemComponent,
- List<QuestionnaireResponse.QuestionnaireResponseItemAnswerComponent>,
+ QuestionnaireResponseItemComponent,
+ List<QuestionnaireResponseItemAnswerComponent>,
  ) -> Unit =
  { questionnaireItem, questionnaireResponseItem, answers ->
  // TODO(jingtang10): update the questionnaire response item pre-order list and the parent map
@@ -377,9 +388,7 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  if (questionnaireResponseItem.answer.hasDifferentAnswerSet(calculatedAnswers)) {
  questionnaireResponseItem.answer =
  calculatedAnswers.map {
- QuestionnaireResponse.QuestionnaireResponseItemAnswerComponent().apply {
- value = it
- }
+ QuestionnaireResponseItemAnswerComponent().apply { value = it }
  }
  }
  }
@@ -537,7 +546,7 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  */
  private fun getQuestionnaireAdapterItems(
  questionnaireItemList: List<Questionnaire.QuestionnaireItemComponent>,
- questionnaireResponseItemList: List<QuestionnaireResponse.QuestionnaireResponseItemComponent>,
+ questionnaireResponseItemList: List<QuestionnaireResponseItemComponent>,
  ): List<QuestionnaireAdapterItem> {
  var responseIndex = 0
  return questionnaireItemList
@@ -564,16 +573,21 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  */
  private fun getQuestionnaireAdapterItems(
  questionnaireItem: Questionnaire.QuestionnaireItemComponent,
- questionnaireResponseItem: QuestionnaireResponse.QuestionnaireResponseItemComponent,
+ questionnaireResponseItem: QuestionnaireResponseItemComponent,
  ): List<QuestionnaireAdapterItem> {
- // Disabled/hidden questions should not get QuestionnaireItemViewItem instances
+ // Hidden questions should not get QuestionnaireItemViewItem instances
+ if (questionnaireItem.isHidden) return emptyList()
  val enabled =
  EnablementEvaluator(questionnaireResponse)
  .evaluate(questionnaireItem, questionnaireResponseItem)
- if (!enabled || questionnaireItem.isHidden) {
+ // Disabled questions should not get QuestionnaireItemViewItem instances
+ if (!enabled) {
+ cacheDisabledQuestionnaireItemAnswers(questionnaireResponseItem)
  return emptyList()
  }
 
+ restoreFromDisabledQuestionnaireItemAnswersCache(questionnaireResponseItem)
+
  // Determine the validation result, which will be displayed on the item itself
  val validationResult =
  if (modifiedQuestionnaireResponseItemSet.contains(questionnaireResponseItem) ||
@@ -603,7 +617,7 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  )
  )
  )
- val nestedResponses: List<List<QuestionnaireResponse.QuestionnaireResponseItemComponent>> =
+ val nestedResponses: List<List<QuestionnaireResponseItemComponent>> =
  when {
  // Repeated questions have one answer item per response instance, which we must display
  // after the question.
@@ -630,10 +644,37 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  return items
  }
 
+ /**
+ * If the item is not enabled, clear the answers that it may have from the previous enabled state.
+ * This will also prevent any questionnaire item that depends on the answer of this questionnaire
+ * item to be wrongly evaluated as well.
+ */
+ private fun cacheDisabledQuestionnaireItemAnswers(
+ questionnaireResponseItem: QuestionnaireResponseItemComponent
+ ) {
+ if (questionnaireResponseItem.hasAnswer()) {
+ responseItemToAnswersMapForDisabledQuestionnaireItem[questionnaireResponseItem] =
+ questionnaireResponseItem.answer
+ questionnaireResponseItem.answer = listOf()
+ }
+ }
+
+ /**
+ * If the questionnaire item was previously disabled, check the cache to restore previous answers.
+ */
+ private fun restoreFromDisabledQuestionnaireItemAnswersCache(
+ questionnaireResponseItem: QuestionnaireResponseItemComponent
+ ) {
+ if (responseItemToAnswersMapForDisabledQuestionnaireItem.contains(questionnaireResponseItem)) {
+ questionnaireResponseItem.answer =
+ responseItemToAnswersMapForDisabledQuestionnaireItem.remove(questionnaireResponseItem)
+ }
+ }
+
  private fun getEnabledResponseItems(
  questionnaireItemList: List<Questionnaire.QuestionnaireItemComponent>,
- questionnaireResponseItemList: List<QuestionnaireResponse.QuestionnaireResponseItemComponent>,
- ): List<QuestionnaireResponse.QuestionnaireResponseItemComponent> {
+ questionnaireResponseItemList: List<QuestionnaireResponseItemComponent>,
+ ): List<QuestionnaireResponseItemComponent> {
  val enablementEvaluator = EnablementEvaluator(questionnaireResponse)
  val responseItemKeys = questionnaireResponseItemList.map { it.linkId }
  return questionnaireItemList
@@ -680,15 +721,15 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
  */
  private fun createRepeatedGroupResponse(
  questionnaireItem: Questionnaire.QuestionnaireItemComponent,
- questionnaireResponseItem: QuestionnaireResponse.QuestionnaireResponseItemComponent,
- ): List<QuestionnaireResponse.QuestionnaireResponseItemComponent> {
+ questionnaireResponseItem: QuestionnaireResponseItemComponent,
+ ): List<QuestionnaireResponseItemComponent> {
  val individualQuestions = questionnaireItem.item
  return questionnaireResponseItem.answer.map { repeatedGroupInstance ->
  val responsesToIndividualQuestions = repeatedGroupInstance.item
  check(responsesToIndividualQuestions.size == individualQuestions.size) {
  "Repeated groups responses must have the same # of responses as the group has questions"
  }
- QuestionnaireResponse.QuestionnaireResponseItemComponent().apply {
+ QuestionnaireResponseItemComponent().apply {
  linkId = questionnaireItem.linkId
  text = questionnaireItem.localizedTextSpanned?.toString()
  item =