Fix #4450: Add next and previous card options on revision screen

app/src/main/java/org/oppia/android/app/topic/revisioncard/RevisionCardActivity.kt

@@ -2,22 +2,30 @@ package org.oppia.android.app.topic.revisioncard
 
 import android.content.Context
 import android.content.Intent
+import android.os.Build
 import android.os.Bundle
 import android.view.Menu
 import android.view.MenuItem
+import androidx.annotation.RequiresApi
+import androidx.core.content.res.ResourcesCompat
 import org.oppia.android.R
 import org.oppia.android.app.activity.ActivityComponentImpl
 import org.oppia.android.app.activity.InjectableAppCompatActivity
+import org.oppia.android.app.topic.RouteToRevisionCardListener
 import org.oppia.android.app.topic.conceptcard.ConceptCardListener
 import javax.inject.Inject
 
 /** Activity for revision card. */
 class RevisionCardActivity :
-  InjectableAppCompatActivity(), ReturnToTopicClickListener, ConceptCardListener {
+  InjectableAppCompatActivity(),
+  ReturnToTopicClickListener,
+  ConceptCardListener,
+  RouteToRevisionCardListener {
 
   @Inject
   lateinit var revisionCardActivityPresenter: RevisionCardActivityPresenter
 
+  @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     (activityComponent as ActivityComponentImpl).inject(this)
@@ -29,6 +37,15 @@ class RevisionCardActivity :
       val subtopicId = intent.getIntExtra(SUBTOPIC_ID_EXTRA_KEY, -1)
       revisionCardActivityPresenter.handleOnCreate(internalProfileId, topicId, subtopicId)
     }
+    supportActionBar?.setBackgroundDrawable(
+      ResourcesCompat.getDrawable(
+        resources,
+        R.color.color_def_oppia_brown_dark,
+        theme
+      )
+    )
+    window.statusBarColor =
+      ResourcesCompat.getColor(resources, R.color.color_def_oppia_brown_dark2, theme)
   }
 
   override fun onCreateOptionsMenu(menu: Menu?): Boolean {
@@ -60,6 +77,18 @@ class RevisionCardActivity :
     }
   }
 
+  override fun routeToRevisionCard(internalProfileId: Int, topicId: String, subtopicId: Int) {
+    startActivity(
+      createRevisionCardActivityIntent(
+        this,
+        internalProfileId,
+        topicId,
+        subtopicId
+      )
+    )
+    this.finish()
+  }
+
   override fun onReturnToTopicClicked() {
     onBackPressed()
   }

app/src/main/java/org/oppia/android/app/topic/revisioncard/RevisionCardFragmentPresenter.kt

@@ -3,9 +3,12 @@ package org.oppia.android.app.topic.revisioncard
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
 import org.oppia.android.app.fragment.FragmentScope
+import org.oppia.android.app.model.EphemeralSubtopic
 import org.oppia.android.app.model.ProfileId
+import org.oppia.android.app.topic.RouteToRevisionCardListener
 import org.oppia.android.app.topic.conceptcard.ConceptCardFragment
 import org.oppia.android.app.topic.conceptcard.ConceptCardFragment.Companion.CONCEPT_CARD_DIALOG_FRAGMENT_TAG
 import org.oppia.android.app.translation.AppLanguageResourceHandler
@@ -21,6 +24,7 @@ import javax.inject.Inject
 /** Presenter for [RevisionCardFragment], sets up bindings from ViewModel. */
 @FragmentScope
 class RevisionCardFragmentPresenter @Inject constructor(
+  activity: AppCompatActivity,
   private val fragment: Fragment,
   private val oppiaLogger: OppiaLogger,
   private val htmlParserFactory: HtmlParser.Factory,
@@ -31,6 +35,7 @@ class RevisionCardFragmentPresenter @Inject constructor(
   private val appLanguageResourceHandler: AppLanguageResourceHandler
 ) : HtmlParser.CustomOppiaTagActionListener {
   private lateinit var profileId: ProfileId
+  private val routeToReviewListener = activity as RouteToRevisionCardListener
 
   fun handleCreateView(
     inflater: LayoutInflater,
@@ -58,6 +63,8 @@ class RevisionCardFragmentPresenter @Inject constructor(
       it.lifecycleOwner = fragment
     }
 
+    setupRevisionNavigationCards(binding, topicId, subtopicId)
+
     viewModel.revisionCardLiveData.observe(
       fragment,
       { ephemeralRevisionCard ->
@@ -79,6 +86,45 @@ class RevisionCardFragmentPresenter @Inject constructor(
     return binding.root
   }
 
+  private fun setupRevisionNavigationCards(
+    binding: RevisionCardFragmentBinding,
+    topicId: String,
+    subtopicId: Int
+  ) {
+    binding.nextSubtopicImageView.setEntityType(entityType)
+    binding.prevSubtopicImageView.setEntityType(entityType)
+
+    binding.previousNavigationCard.setOnClickListener {
+      routeToReviewListener.routeToRevisionCard(profileId.internalId, topicId, subtopicId - 1)
+    }
+
+    binding.nextNavigationCard.setOnClickListener {
+      routeToReviewListener.routeToRevisionCard(profileId.internalId, topicId, subtopicId + 1)
+    }
+
+    getReviewCardViewModel().nextSubtopicLiveData.observe(fragment) { nextSubtopic ->
+      if (nextSubtopic == EphemeralSubtopic.getDefaultInstance()) {
+        binding.nextNavigationCard.visibility = View.INVISIBLE
+      }
+      binding.nextSubtopicImageView.setLessonThumbnail(nextSubtopic.subtopic.subtopicThumbnail)
+      binding.nextSubtopicTitle.text = translationController.extractString(
+        nextSubtopic.subtopic.title,
+        nextSubtopic.writtenTranslationContext
+      )
+    }
+
+    getReviewCardViewModel().previousSubtopicLiveData.observe(fragment) { previousSubtopic ->
+      if (previousSubtopic.equals(EphemeralSubtopic.getDefaultInstance())) {
+        binding.previousNavigationCard.visibility = View.INVISIBLE
+      }
+      binding.prevSubtopicImageView.setLessonThumbnail(previousSubtopic.subtopic.subtopicThumbnail)
+      binding.prevSubtopicTitle.text = translationController.extractString(
+        previousSubtopic.subtopic.title,
+        previousSubtopic.writtenTranslationContext
+      )
+    }
+  }
+
   /** Dismisses the concept card fragment if it's currently active in this fragment. */
   fun dismissConceptCard() {
     fragment.childFragmentManager.findFragmentByTag(

app/src/main/java/org/oppia/android/app/topic/revisioncard/RevisionCardViewModel.kt

@@ -6,6 +6,8 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.Transformations
 import org.oppia.android.app.fragment.FragmentScope
 import org.oppia.android.app.model.EphemeralRevisionCard
+import org.oppia.android.app.model.EphemeralSubtopic
+import org.oppia.android.app.model.EphemeralTopic
 import org.oppia.android.app.model.ProfileId
 import org.oppia.android.app.viewmodel.ObservableViewModel
 import org.oppia.android.domain.oppialogger.OppiaLogger
@@ -21,7 +23,7 @@ class RevisionCardViewModel @Inject constructor(
   private val topicController: TopicController,
   private val oppiaLogger: OppiaLogger
 ) : ObservableViewModel() {
-  private lateinit var topicId: String
+  lateinit var topicId: String
   private var subtopicId: Int = 0
   private lateinit var profileId: ProfileId
 
@@ -32,6 +34,53 @@ class RevisionCardViewModel @Inject constructor(
     processRevisionCardLiveData()
   }
 
+  private val topicLiveData: LiveData<AsyncResult<EphemeralTopic>> by lazy {
+    getTopicResultLiveData()
+  }
+
+  private fun getTopicResultLiveData(): LiveData<AsyncResult<EphemeralTopic>> {
+    return topicController.getTopic(profileId, topicId).toLiveData()
+  }
+
+  val nextSubtopicLiveData: LiveData<EphemeralSubtopic> by lazy {
+    Transformations.map(topicLiveData, ::processNextSubtopicData)
+  }
+
+  val previousSubtopicLiveData: LiveData<EphemeralSubtopic> by lazy {
+    Transformations.map(topicLiveData, ::processPreviousSubtopicData)
+  }
+
+  private fun processPreviousSubtopicData(
+    topicLiveData: AsyncResult<EphemeralTopic>
+  ): EphemeralSubtopic? {
+    return if (subtopicId == 0) EphemeralSubtopic.getDefaultInstance()
+    else {
+      when (topicLiveData) {
+        is AsyncResult.Success -> {
+          val topic = topicLiveData.value
+          topic.subtopicsList.find {
+            it.subtopic.subtopicId == subtopicId - 1
+          } ?: EphemeralSubtopic.getDefaultInstance()
+        }
+        else -> EphemeralSubtopic.getDefaultInstance()
+      }
+    }
+  }
+
+  private fun processNextSubtopicData(
+    topicLiveData: AsyncResult<EphemeralTopic>
+  ): EphemeralSubtopic? {
+    return when (topicLiveData) {
+      is AsyncResult.Success -> {
+        val topic = topicLiveData.value
+        topic.subtopicsList.find {
+          it.subtopic.subtopicId == subtopicId + 1
+        } ?: EphemeralSubtopic.getDefaultInstance()
+      }
+      else -> EphemeralSubtopic.getDefaultInstance()
+    }
+  }
+
   fun clickReturnToTopic(@Suppress("UNUSED_PARAMETER") v: View) {
     returnToTopicClickListener.onReturnToTopicClicked()
   }

app/src/main/res/layout-sw600dp/revision_card_fragment.xml

@@ -1,4 +1,5 @@
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto">
 
   <data>
 
@@ -34,21 +35,127 @@
           style="@style/Body"
           android:layout_marginTop="@dimen/revision_card_fragment_layout_text_margin_top" />
 
-        <Button
-          android:id="@+id/revision_card_return_button"
-          style="@style/StateButtonActive"
-          android:layout_width="wrap_content"
+        <androidx.constraintlayout.widget.ConstraintLayout
+          android:layout_width="match_parent"
           android:layout_height="wrap_content"
-          android:layout_gravity="end"
-          android:layout_marginTop="@dimen/revision_card_fragment_layout_button_margin_top"
-          android:background="@drawable/state_button_primary_background"
-          android:onClick="@{viewModel::clickReturnToTopic}"
-          android:paddingStart="32dp"
-          android:paddingEnd="32dp"
-          android:text="@string/return_to_topic"
-          android:textAllCaps="true"
-          android:textColor="@color/color_def_white"
-          android:textSize="14sp" />
+          android:layout_marginTop="50dp">
+
+          <TextView
+            android:id="@+id/continue_studying_text_view"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="28dp"
+            android:layout_marginEnd="28dp"
+            android:text="@string/continue_studying"
+            android:textColor="@color/color_def_black"
+            android:textSize="20sp"
+            android:textStyle="bold"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent" />
+
+          <com.google.android.material.card.MaterialCardView
+            android:id="@+id/previous_navigation_card"
+            android:layout_width="144dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="28dp"
+            android:layout_marginTop="16dp"
+            android:layout_marginEnd="28dp"
+            android:layout_marginBottom="@dimen/topic_revision_summary_view_container_margin_bottom"
+            android:clipToPadding="true"
+            app:cardBackgroundColor="@color/color_def_white"
+            app:cardCornerRadius="4dp"
+            app:cardElevation="4dp"
+            app:cardMaxElevation="4dp"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/continue_studying_text_view">
+
+            <androidx.constraintlayout.widget.ConstraintLayout
+              android:layout_width="match_parent"
+              android:layout_height="wrap_content">
+
+              <org.oppia.android.app.customview.LessonThumbnailImageView
+                android:id="@+id/prev_subtopic_image_view"
+                android:layout_width="0dp"
+                android:layout_height="0dp"
+                android:importantForAccessibility="no"
+                app:entityId="@{viewModel.topicId}"
+                app:layout_constraintDimensionRatio="H,4:3"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent" />
+
+              <TextView
+                android:id="@+id/prev_subtopic_title"
+                style="@style/TextViewStart"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:background="@color/color_def_oppia_brown_dark"
+                android:ellipsize="end"
+                android:fontFamily="sans-serif"
+                android:lines="3"
+                android:paddingStart="@dimen/topic_revision_summary_view_subtopic_title_text_view_padding_start"
+                android:paddingTop="8dp"
+                android:paddingEnd="@dimen/topic_revision_summary_view_subtopic_title_text_view_padding_end"
+                android:paddingBottom="16dp"
+                android:textColor="@color/color_def_white"
+                android:textSize="14sp"
+                android:textStyle="bold"
+                app:layout_constraintTop_toBottomOf="@id/prev_subtopic_image_view" />
+            </androidx.constraintlayout.widget.ConstraintLayout>
+          </com.google.android.material.card.MaterialCardView>
+
+          <com.google.android.material.card.MaterialCardView
+            android:id="@+id/next_navigation_card"
+            android:layout_width="144dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="28dp"
+            android:layout_marginTop="16dp"
+            android:layout_marginEnd="28dp"
+            android:layout_marginBottom="@dimen/topic_revision_summary_view_container_margin_bottom"
+            android:clipToPadding="true"
+            app:cardBackgroundColor="@color/color_def_white"
+            app:cardCornerRadius="4dp"
+            app:cardElevation="4dp"
+            app:cardMaxElevation="4dp"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/continue_studying_text_view">
+
+            <androidx.constraintlayout.widget.ConstraintLayout
+              android:layout_width="match_parent"
+              android:layout_height="wrap_content">
+
+              <org.oppia.android.app.customview.LessonThumbnailImageView
+                android:id="@+id/next_subtopic_image_view"
+                android:layout_width="0dp"
+                android:layout_height="0dp"
+                android:importantForAccessibility="no"
+                app:entityId="@{viewModel.topicId}"
+                app:layout_constraintDimensionRatio="H,4:3"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent" />
+
+              <TextView
+                android:id="@+id/next_subtopic_title"
+                style="@style/TextViewStart"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:background="@color/color_def_oppia_brown_dark"
+                android:ellipsize="end"
+                android:fontFamily="sans-serif"
+                android:lines="3"
+                android:paddingStart="@dimen/topic_revision_summary_view_subtopic_title_text_view_padding_start"
+                android:paddingTop="8dp"
+                android:paddingEnd="@dimen/topic_revision_summary_view_subtopic_title_text_view_padding_end"
+                android:paddingBottom="16dp"
+                android:textColor="@color/color_def_white"
+                android:textSize="14sp"
+                android:textStyle="bold"
+                app:layout_constraintTop_toBottomOf="@id/next_subtopic_image_view" />
+            </androidx.constraintlayout.widget.ConstraintLayout>
+          </com.google.android.material.card.MaterialCardView>
+        </androidx.constraintlayout.widget.ConstraintLayout>
       </LinearLayout>
     </LinearLayout>
   </ScrollView>