Fix #1593: Landscape support for Hints & Solution (#1615)

* fix landscape crash

* fix visibility issues

* fix collapse expanded items on click other item

* fix ktlint

app/src/main/java/org/oppia/app/hintsandsolution/ExpandedHintListIndexListener.kt

@@ -5,5 +5,13 @@ package org.oppia.app.hintsandsolution
  * This mainly helps to maintain the state during configuration change.
  */
 interface ExpandedHintListIndexListener {
+
+  /** Manage expanded list icon */
   fun onExpandListIconClicked(index: Int?)
+
+  /** Manage reveal hint button visibility while orientation change */
+  fun onRevealHintClicked(index: Int?, isHintRevealed: Boolean?)
+
+  /** Manage reveal solution button visibility while orientation change */
+  fun onRevealSolutionClicked(solutionIndex: Int?, isSolutionRevealed: Boolean?)
 }

app/src/main/java/org/oppia/app/hintsandsolution/HintsAndSolutionAdapter.kt

@@ -24,7 +24,11 @@ class HintsAndSolutionAdapter(
   private val explorationId: String?,
   private val htmlParserFactory: HtmlParser.Factory,
   private val resourceBucketName: String,
-  private val entityType: String
+  private val entityType: String,
+  private val hintIndex: Int?,
+  private val isHintRevealed: Boolean?,
+  private val solutionIndex: Int?,
+  private val isSolutionRevealed: Boolean?
 ) :
   RecyclerView.Adapter<RecyclerView.ViewHolder>() {
 
@@ -94,6 +98,15 @@ class HintsAndSolutionAdapter(
         isHintListVisible = currentExpandedHintListIndex!! == position
       }
       binding.isListExpanded = isHintListVisible
+
+      hintIndex?.let {
+        isHintRevealed?.let {
+          if (hintIndex == position && isHintRevealed) {
+            hintsViewModel.isHintRevealed.set(true)
+          }
+        }
+      }
+
       binding.viewModel = hintsViewModel
 
       if (hintsViewModel.isHintRevealed.get()!!) {
@@ -114,14 +127,19 @@ class HintsAndSolutionAdapter(
         binding.root.visibility = View.VISIBLE
         binding.revealHintButton.setOnClickListener {
           hintsViewModel.isHintRevealed.set(true)
+          expandedHintListIndexListener.onRevealHintClicked(position, /* isHintRevealed= */ true)
           (fragment.requireActivity() as? RevealHintListener)?.revealHint(true, position)
+          val previousIndex: Int? = currentExpandedHintListIndex
           currentExpandedHintListIndex =
             if (currentExpandedHintListIndex != null && currentExpandedHintListIndex == position) {
               null
             } else {
               position
             }
           expandedHintListIndexListener.onExpandListIconClicked(currentExpandedHintListIndex)
+          if (previousIndex != null && previousIndex != currentExpandedHintListIndex) {
+            notifyItemChanged(previousIndex)
+          }
         }
       }
 
@@ -161,6 +179,15 @@ class HintsAndSolutionAdapter(
         isHintListVisible = currentExpandedHintListIndex!! == position
       }
       binding.isListExpanded = isHintListVisible
+
+      solutionIndex?.let {
+        isSolutionRevealed?.let {
+          if (solutionIndex == position && isSolutionRevealed) {
+            solutionViewModel.isSolutionRevealed.set(true)
+          }
+        }
+      }
+
       binding.viewModel = solutionViewModel
       binding.root.visibility = View.GONE
       binding.solutionTitle.text = solutionViewModel.title.get()!!.capitalize()
@@ -226,8 +253,24 @@ class HintsAndSolutionAdapter(
     if (itemList[itemList.size - 1] is SolutionViewModel) {
       val solutionViewModel = itemList[itemList.size - 1] as SolutionViewModel
       solutionViewModel.isSolutionRevealed.set(saveUserChoice)
+      expandedHintListIndexListener.onRevealSolutionClicked(
+        /* solutionIndex= */ itemList.size - 1,
+        /* isSolutionRevealed= */ true
+      )
       (fragment.requireActivity() as? RevealSolutionInterface)?.revealSolution(saveUserChoice)
-      notifyItemChanged(itemList.size - 1)
+      val previousIndex: Int? = currentExpandedHintListIndex
+      currentExpandedHintListIndex =
+        if (currentExpandedHintListIndex != null &&
+          currentExpandedHintListIndex == itemList.size - 1
+        ) {
+          null
+        } else {
+          itemList.size - 1
+        }
+      expandedHintListIndexListener.onExpandListIconClicked(currentExpandedHintListIndex)
+      if (previousIndex != null && previousIndex != currentExpandedHintListIndex) {
+        notifyItemChanged(previousIndex)
+      }
     }
   }
 

app/src/main/java/org/oppia/app/hintsandsolution/HintsAndSolutionDialogFragment.kt

@@ -11,6 +11,11 @@ import org.oppia.app.model.State
 import javax.inject.Inject
 
 private const val CURRENT_EXPANDED_LIST_INDEX_SAVED_KEY = "CURRENT_EXPANDED_LIST_INDEX"
+private const val STATE_SAVED_KEY = "STATE_SAVED_KEY"
+private const val HINT_INDEX_SAVED_KEY = "HINT_INDEX_SAVED_KEY"
+private const val IS_HINT_REVEALED_SAVED_KEY = "IS_HINT_REVEALED_SAVED_KEY"
+private const val SOLUTION_INDEX_SAVED_KEY = "SOLUTION_INDEX_SAVED_KEY"
+private const val IS_SOLUTION_REVEALED_SAVED_KEY = "IS_SOLUTION_REVEALED_SAVED_KEY"
 
 /* Fragment that displays a fullscreen dialog for Hints and Solutions. */
 class HintsAndSolutionDialogFragment :
@@ -25,6 +30,11 @@ class HintsAndSolutionDialogFragment :
 
   private var currentExpandedHintListIndex: Int? = null
 
+  private var index: Int? = null
+  private var isHintRevealed: Boolean? = null
+  private var solutionIndex: Int? = null
+  private var isSolutionRevealed: Boolean? = null
+
   companion object {
 
     internal const val ID_ARGUMENT_KEY = "ID"
@@ -74,6 +84,13 @@ class HintsAndSolutionDialogFragment :
       if (currentExpandedHintListIndex == -1) {
         currentExpandedHintListIndex = null
       }
+      state = State.parseFrom(savedInstanceState.getByteArray(STATE_SAVED_KEY)!!)
+      index = savedInstanceState.getInt(HINT_INDEX_SAVED_KEY, -1)
+      if (index == -1) index = null
+      isHintRevealed = savedInstanceState.getBoolean(IS_HINT_REVEALED_SAVED_KEY, false)
+      solutionIndex = savedInstanceState.getInt(SOLUTION_INDEX_SAVED_KEY, -1)
+      if (solutionIndex == -1) solutionIndex = null
+      isSolutionRevealed = savedInstanceState.getBoolean(IS_SOLUTION_REVEALED_SAVED_KEY, false)
     }
     val args =
       checkNotNull(
@@ -100,7 +117,11 @@ class HintsAndSolutionDialogFragment :
       currentExpandedHintListIndex,
       newAvailableHintIndex,
       allHintsExhausted,
-      this as ExpandedHintListIndexListener
+      this as ExpandedHintListIndexListener,
+      index,
+      isHintRevealed,
+      solutionIndex,
+      isSolutionRevealed
     )
   }
 
@@ -114,6 +135,19 @@ class HintsAndSolutionDialogFragment :
     if (currentExpandedHintListIndex != null) {
       outState.putInt(CURRENT_EXPANDED_LIST_INDEX_SAVED_KEY, currentExpandedHintListIndex!!)
     }
+    if (index != null) {
+      outState.putInt(HINT_INDEX_SAVED_KEY, index!!)
+    }
+    if (isHintRevealed != null) {
+      outState.putBoolean(IS_HINT_REVEALED_SAVED_KEY, isHintRevealed!!)
+    }
+    if (solutionIndex != null) {
+      outState.putInt(SOLUTION_INDEX_SAVED_KEY, solutionIndex!!)
+    }
+    if (isSolutionRevealed != null) {
+      outState.putBoolean(IS_SOLUTION_REVEALED_SAVED_KEY, isSolutionRevealed!!)
+    }
+    outState.putByteArray(STATE_SAVED_KEY, state.toByteArray())
   }
 
   override fun onExpandListIconClicked(index: Int?) {
@@ -125,6 +159,21 @@ class HintsAndSolutionDialogFragment :
     hintsAndSolutionDialogFragmentPresenter.handleRevealSolution(saveUserChoice)
   }
 
+  override fun onRevealHintClicked(index: Int?, isHintRevealed: Boolean?) {
+    this.index = index
+    this.isHintRevealed = isHintRevealed
+    hintsAndSolutionDialogFragmentPresenter.onRevealHintClicked(index, isHintRevealed)
+  }
+
+  override fun onRevealSolutionClicked(solutionIndex: Int?, isSolutionRevealed: Boolean?) {
+    this.solutionIndex = solutionIndex
+    this.isSolutionRevealed = isSolutionRevealed
+    hintsAndSolutionDialogFragmentPresenter.onRevealSolutionClicked(
+      solutionIndex,
+      isSolutionRevealed
+    )
+  }
+
   fun loadState(state: State) {
     this.state = state
   }

app/src/main/java/org/oppia/app/hintsandsolution/HintsAndSolutionDialogFragmentPresenter.kt

@@ -10,7 +10,6 @@ import org.oppia.app.fragment.FragmentScope
 import org.oppia.app.model.State
 import org.oppia.app.viewmodel.ViewModelProvider
 import org.oppia.util.gcsresource.DefaultResourceBucketName
-import org.oppia.util.logging.ConsoleLogger
 import org.oppia.util.parser.ExplorationHtmlParserEntityType
 import org.oppia.util.parser.HtmlParser
 import javax.inject.Inject
@@ -21,12 +20,15 @@ class HintsAndSolutionDialogFragmentPresenter @Inject constructor(
   private val fragment: Fragment,
   private val viewModelProvider: ViewModelProvider<HintsViewModel>,
   private val htmlParserFactory: HtmlParser.Factory,
-  private val logger: ConsoleLogger,
   @DefaultResourceBucketName private val resourceBucketName: String,
   @ExplorationHtmlParserEntityType private val entityType: String
 ) {
 
   private var currentExpandedHintListIndex: Int? = null
+  private var index: Int? = null
+  private var isHintRevealed: Boolean? = null
+  private var solutionIndex: Int? = null
+  private var isSolutionRevealed: Boolean? = null
   private lateinit var expandedHintListIndexListener: ExpandedHintListIndexListener
   private lateinit var hintsAndSolutionAdapter: HintsAndSolutionAdapter
   private lateinit var binding: HintsAndSolutionFragmentBinding
@@ -48,13 +50,21 @@ class HintsAndSolutionDialogFragmentPresenter @Inject constructor(
     currentExpandedHintListIndex: Int?,
     newAvailableHintIndex: Int,
     allHintsExhausted: Boolean,
-    expandedHintListIndexListener: ExpandedHintListIndexListener
+    expandedHintListIndexListener: ExpandedHintListIndexListener,
+    index: Int?,
+    isHintRevealed: Boolean?,
+    solutionIndex: Int?,
+    isSolutionRevealed: Boolean?
   ): View? {
 
     binding =
       HintsAndSolutionFragmentBinding.inflate(inflater, container, /* attachToRoot= */ false)
     this.currentExpandedHintListIndex = currentExpandedHintListIndex
     this.expandedHintListIndexListener = expandedHintListIndexListener
+    this.index = index
+    this.isHintRevealed = isHintRevealed
+    this.solutionIndex = solutionIndex
+    this.isSolutionRevealed = isSolutionRevealed
     binding.hintsAndSolutionToolbar.setNavigationIcon(R.drawable.ic_close_white_24dp)
     binding.hintsAndSolutionToolbar.setNavigationOnClickListener {
       (fragment.requireActivity() as? HintsAndSolutionListener)?.dismiss()
@@ -89,7 +99,11 @@ class HintsAndSolutionDialogFragmentPresenter @Inject constructor(
           viewModel.explorationId.get(),
           htmlParserFactory,
           resourceBucketName,
-          entityType
+          entityType,
+          index,
+          isHintRevealed,
+          solutionIndex,
+          isSolutionRevealed
         )
 
       binding.hintsAndSolutionRecyclerView.apply {
@@ -125,4 +139,14 @@ class HintsAndSolutionDialogFragmentPresenter @Inject constructor(
     if (index != null)
       hintsAndSolutionAdapter.notifyItemChanged(index)
   }
+
+  fun onRevealHintClicked(index: Int?, isHintRevealed: Boolean?) {
+    this.index = index
+    this.isHintRevealed = isHintRevealed
+  }
+
+  fun onRevealSolutionClicked(solutionIndex: Int?, isSolutionRevealed: Boolean?) {
+    this.solutionIndex = solutionIndex
+    this.isSolutionRevealed = isSolutionRevealed
+  }
 }

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

@@ -88,6 +88,12 @@
       </FrameLayout>
     </androidx.constraintlayout.widget.ConstraintLayout>
 
+    <FrameLayout
+      android:id="@+id/hints_and_solution_fragment_placeholder"
+      android:layout_width="match_parent"
+      android:layout_height="match_parent">
+    </FrameLayout>
+
     <FrameLayout
       android:id="@+id/hints_and_solution_fragment_container"
       android:layout_width="wrap_content"