Fix #161: Exploration player contentcard supports rich-text part. (#275)

* Introduce first pass interface for ExplorationProgressController.

* Fill in the stubbed logic for ExplorationProgressController. Still no
tests to verify correctness.

Also, added a method to facilitate notifying of DataProvider changes on
the UI thread.

* Fix lateinit issue in ExplorationProgressController due to wrongly ordered
initialization.

* Fix a variaty of issues in the exp progress controller, properly hook it up to
the data controller, and start adding tests.

* Created a separate ExplorationRetriever, hooked up
AnswerClassificationController, and attempted to make
ExplorationProgressController thread-safe.

The thread-safety led to significant interface changes in the progress
controller, and led to discovering some issues with the mediator live data
approach to interop coroutines and LiveData. This locking mechanism will
need to change since the optimal solution requires resolving #90.

* Change the locking mechanism for ExplorationProgressController to work
with the current MediatorLiveData implementation (see #90 for more
context). Fix existing progress controller tests and add a few more. All
current progress controller tests are passing.

* Finish tests for ExplorationProgressController and add test classification
support for the second test exploration (about_oppia).

* craeted image parser

* ObservableViewModel

* Load exploration and open ExplorationActivity

* Test case for load exploration

* fetch exploration

* Connection with StateFragment

* update

* update

* working on fetching customization_args

* Update StateFragmentPresenter.kt

* Separated this in its own PR

* Delete UrlImageParser.kt

Separated this in its own PR.

* Update StateFragmentPresenter.kt

* Update build.gradle

* Create HtmlParser.kt

* Update HtmlParser.kt

* Update HtmlParser.kt

* Update HtmlParser.kt

* working on testcases

* Update HtmlParserTestActivty.kt

* Update HtmlParserTestActivty.kt

* added testcases.

* Update AndroidManifest.xml

* Update InteractionAdapter.kt

* Update InteractionAdapter.kt

* Update HtmlParser.kt

* corrected variable names.

* updated variables.

* Update HtmlParser.kt

* Update HtmlParser.kt

* Update HtmlParserTestActivty.kt

* Update HtmlParser.kt

* Delete InteractionAdapter.kt

* deteted unused xml files

* merged html code.

* Update HtmlParser.kt

* Delete UrlImageParserTest.kt

* used dagger injection for UrlImageParser.

* Update HtmlParserTestActivty.kt

* Update HtmlParserTestActivty.kt

* Update HtmlParser.kt

* Update HtmlParserTestActivty.kt

* updated tests

* updated test

* moved to testing package

* Update HtmlParserTestActivty.kt

* Update HtmlParserTestActivty.kt

* fix issues

* fix issues.

* fixed issues

* fixed issues.

* Update activity_test_html_parser.xml

* fixes

* Update HtmlParserTest.kt

* Update HtmlParserTest.kt

* fixed issues.

* fixing issues.

* made use of factory

* Update HtmlParserTest.kt

* Update UrlImageParser.kt

* Update AndroidManifest.xml

* Update HtmlParserTestActivity.kt

* nit

* Update AudioFragmentTest.kt

* updated

* fixes

* Update UrlImageParser.kt

* Not used in this.

* fixes

* Not used.

* Update CellularDataDialogFragmentTest.kt

* reverted

* Update CellularDataDialogFragmentTest.kt

* fixes

* Update ImageLoader.kt

* Update HtmlParser.kt

* Update HtmlParser.kt

* Update build.gradle

* fixed issues.

* Update UrlImageParser.kt

* Update UrlImageParser.kt

* Update UrlImageParser.kt

* Update ImageParsingAnnotations.kt

* working on image loader

* Injected ImageLoader

* updated image loader.

* Update ActivityComponent.kt

* Update HtmlParserTestActivity.kt

* Update GlideImageLoader.kt

* removed annotation

* Update HtmlParser.kt

* line break

* fix

* fix comments

* Update UrlImageParser.kt

* Update UrlImageParser.kt

* injected context

* working on testcase.

* testcase added

* added test case

* testcases

* Update build.gradle

* Update AndroidManifest.xml

* fixes

* Update UrlImageParserTest.kt

* changed to CutomTarget

* Update UrlImageParserTest.kt

* updated.

* Update UrlImageParserTest.kt

* Update HtmlParserTestActivity.kt

* Update misc.xml

* Update GlideImageLoaderModule.kt

* updated with image parser

* Update StateFragmentContentCardTest.kt

* Update HtmlParserTest.kt

* deleted test class for loading image and added todo

* updated

* Update build.gradle

* Update GlideImageLoader.kt

* Update build.gradle

* Update UrlImageParser.kt

* updated.

* update

* update

* Update StateFragmentPresenter.kt

* ContentCardTestActivity introduced

* updated test.

* Update AndroidManifest.xml

* Update AndroidManifest.xml

* Update StateFragmentContentCardTest.kt

* renamed file.

* Update state_fragment.xml

* moved test case to stateFragmentTest

* Update StateFragmentTest.kt

*  changes.

* Update content_item.xml

* Update ContentViewModel.kt

* Update StateFragmentTest.kt

* KDoc added

app/src/main/AndroidManifest.xml

@@ -12,6 +12,7 @@
     android:supportsRtl="true"
     android:theme="@style/OppiaTheme">
     <activity android:name=".topic.conceptcard.testing.ConceptCardFragmentTestActivity" />
+    <activity android:name=".testing.ContentCardTestActivity" />
     <activity android:name=".player.state.testing.StateFragmentTestActivity" />
     <activity android:name=".player.exploration.ExplorationActivity" />
     <activity android:name=".topic.questionplayer.QuestionPlayerActivity" />

app/src/main/java/org/oppia/app/activity/ActivityComponent.kt

@@ -12,6 +12,7 @@ import org.oppia.app.player.state.testing.StateFragmentTestActivity
 import org.oppia.app.profile.ProfileActivity
 import org.oppia.app.story.StoryActivity
 import org.oppia.app.testing.BindableAdapterTestActivity
+import org.oppia.app.testing.ContentCardTestActivity
 import org.oppia.app.testing.HtmlParserTestActivity
 import org.oppia.app.topic.TopicActivity
 import org.oppia.app.topic.questionplayer.QuestionPlayerActivity
@@ -32,6 +33,7 @@ interface ActivityComponent {
   fun inject(audioFragmentTestActivity: AudioFragmentTestActivity)
   fun inject(bindableAdapterTestActivity: BindableAdapterTestActivity)
   fun inject(conceptCardFragmentTestActivity: ConceptCardFragmentTestActivity)
+  fun inject(contentCardTestActivity: ContentCardTestActivity)
   fun inject(explorationActivity: ExplorationActivity)
   fun inject(homeActivity: HomeActivity)
   fun inject(htmlParserTestActivty: HtmlParserTestActivity)

app/src/main/java/org/oppia/app/application/ApplicationComponent.kt

@@ -16,6 +16,7 @@ import org.oppia.domain.classify.rules.textinput.TextInputRuleModule
 import org.oppia.util.gcsresource.GcsResourceModule
 import org.oppia.util.logging.LoggerModule
 import org.oppia.util.parser.GlideImageLoaderModule
+import org.oppia.util.parser.HtmlParserEntityTypeModule
 import org.oppia.util.parser.ImageParsingModule
 import org.oppia.util.threading.DispatcherModule
 import javax.inject.Provider
@@ -27,7 +28,8 @@ import javax.inject.Singleton
   ApplicationModule::class, DispatcherModule::class, NetworkModule::class, LoggerModule::class,
   ContinueModule::class, FractionInputModule::class, ItemSelectionInputModule::class, MultipleChoiceInputModule::class,
   NumberWithUnitsRuleModule::class, NumericInputRuleModule::class, TextInputRuleModule::class, InteractionsModule::class,
-  GcsResourceModule::class, ImageParsingModule::class, GlideImageLoaderModule::class
+  GcsResourceModule::class, ImageParsingModule::class, GlideImageLoaderModule::class,
+  HtmlParserEntityTypeModule::class
 ])
 interface ApplicationComponent {
   @Component.Builder

app/src/main/java/org/oppia/app/player/state/StateAdapter.kt

@@ -1,16 +1,21 @@
 package org.oppia.app.player.state
 
+import android.text.Spannable
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import androidx.databinding.DataBindingUtil
 import androidx.databinding.ViewDataBinding
 import androidx.recyclerview.widget.RecyclerView
 import androidx.databinding.library.baseAdapters.BR
+import kotlinx.android.synthetic.main.content_item.view.*
 import kotlinx.android.synthetic.main.state_button_item.view.*
 import org.oppia.app.R
+import org.oppia.app.databinding.ContentItemBinding
 import org.oppia.app.player.state.itemviewmodel.StateButtonViewModel
 import org.oppia.app.player.state.listener.ButtonInteractionListener
 import org.oppia.app.databinding.StateButtonItemBinding
+import org.oppia.app.player.state.itemviewmodel.ContentViewModel
+import org.oppia.util.parser.HtmlParser
 
 @Suppress("unused")
 private const val VIEW_TYPE_CONTENT = 1
@@ -25,7 +30,10 @@ private const val VIEW_TYPE_STATE_BUTTON = 5
 /** Adapter to inflate different items/views inside [RecyclerView]. The itemList consists of various ViewModels. */
 class StateAdapter(
   private val itemList: MutableList<Any>,
-  private val buttonInteractionListener: ButtonInteractionListener
+  private val buttonInteractionListener: ButtonInteractionListener,
+  private val htmlParserFactory: HtmlParser.Factory,
+  private val entityType: String,
+  private val explorationId: String
 ) :
   RecyclerView.Adapter<RecyclerView.ViewHolder>() {
 
@@ -45,7 +53,18 @@ class StateAdapter(
           )
         StateButtonViewHolder(binding, buttonInteractionListener)
       }
-      else -> throw IllegalArgumentException("Invalid view type") as Throwable
+      VIEW_TYPE_CONTENT -> {
+        val inflater = LayoutInflater.from(parent.context)
+        val binding =
+          DataBindingUtil.inflate<ContentItemBinding>(
+            inflater,
+            R.layout.content_item,
+            parent,
+            /* attachToParent= */ false
+          )
+        ContentViewHolder(binding)
+      }
+      else -> throw IllegalArgumentException("Invalid view type")
     }
   }
 
@@ -54,11 +73,15 @@ class StateAdapter(
       VIEW_TYPE_STATE_BUTTON -> {
         (holder as StateButtonViewHolder).bind(itemList[position] as StateButtonViewModel)
       }
+      VIEW_TYPE_CONTENT -> {
+        (holder as ContentViewHolder).bind((itemList[position] as ContentViewModel).htmlContent)
+      }
     }
   }
 
   override fun getItemViewType(position: Int): Int {
     return when (itemList[position]) {
+      is ContentViewModel -> VIEW_TYPE_CONTENT
       is StateButtonViewModel -> {
         stateButtonViewModel = itemList[position] as StateButtonViewModel
         VIEW_TYPE_STATE_BUTTON
@@ -71,6 +94,18 @@ class StateAdapter(
     return itemList.size
   }
 
+  inner class ContentViewHolder(val binding: ViewDataBinding) : RecyclerView.ViewHolder(binding.root) {
+    internal fun bind(rawString: String) {
+      binding.setVariable(BR.htmlContent, rawString)
+      binding.executePendingBindings()
+      val htmlResult: Spannable = htmlParserFactory.create(entityType, explorationId).parseOppiaHtml(
+        rawString,
+        binding.root.content_text_view
+      )
+      binding.root.content_text_view.text = htmlResult
+    }
+  }
+
   private class StateButtonViewHolder(
     val binding: ViewDataBinding,
     private val buttonInteractionListener: ButtonInteractionListener

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

@@ -17,9 +17,11 @@ import org.oppia.app.model.AnswerOutcome
 import org.oppia.app.model.CellularDataPreference
 import org.oppia.app.model.EphemeralState
 import org.oppia.app.model.InteractionObject
+import org.oppia.app.model.SubtitledHtml
 import org.oppia.app.player.audio.AudioFragment
 import org.oppia.app.player.audio.CellularDataDialogFragment
 import org.oppia.app.player.exploration.ExplorationActivity
+import org.oppia.app.player.state.itemviewmodel.ContentViewModel
 import org.oppia.app.player.state.itemviewmodel.StateButtonViewModel
 import org.oppia.app.player.state.listener.ButtonInteractionListener
 import org.oppia.app.viewmodel.ViewModelProvider
@@ -28,6 +30,8 @@ import org.oppia.domain.exploration.ExplorationDataController
 import org.oppia.domain.exploration.ExplorationProgressController
 import org.oppia.util.data.AsyncResult
 import org.oppia.util.logging.Logger
+import org.oppia.util.parser.ExplorationHtmlParserEntityType
+import org.oppia.util.parser.HtmlParser
 import javax.inject.Inject
 
 const val STATE_FRAGMENT_EXPLORATION_ID_ARGUMENT_KEY = "STATE_FRAGMENT_EXPLORATION_ID_ARGUMENT_KEY"
@@ -52,14 +56,16 @@ private const val DEFAULT_CONTINUE_INTERACTION_TEXT_ANSWER = "Please continue."
 /** The presenter for [StateFragment]. */
 @FragmentScope
 class StateFragmentPresenter @Inject constructor(
+  @ExplorationHtmlParserEntityType private val entityType: String,
   private val activity: AppCompatActivity,
   private val fragment: Fragment,
   private val cellularDialogController: CellularDialogController,
   private val stateButtonViewModelProvider: ViewModelProvider<StateButtonViewModel>,
   private val viewModelProvider: ViewModelProvider<StateViewModel>,
   private val explorationDataController: ExplorationDataController,
   private val explorationProgressController: ExplorationProgressController,
-  private val logger: Logger
+  private val logger: Logger,
+  private val htmlParserFactory: HtmlParser.Factory
 ) : ButtonInteractionListener {
 
   private var showCellularDataDialog = true
@@ -90,9 +96,9 @@ class StateFragmentPresenter @Inject constructor(
           useCellularData = prefs.useCellularData
         }
       })
-
-    stateAdapter = StateAdapter(itemList, this as ButtonInteractionListener)
-
+    explorationId = fragment.arguments!!.getString(STATE_FRAGMENT_EXPLORATION_ID_ARGUMENT_KEY)!!
+    stateAdapter =
+      StateAdapter(itemList, this as ButtonInteractionListener, htmlParserFactory, entityType, explorationId)
     binding = StateFragmentBinding.inflate(inflater, container, /* attachToRoot= */ false)
     binding.stateRecyclerView.apply {
       adapter = stateAdapter
@@ -101,7 +107,6 @@ class StateFragmentPresenter @Inject constructor(
       it.stateFragment = fragment as StateFragment
       it.viewModel = getStateViewModel()
     }
-    explorationId = checkNotNull(fragment.arguments!!.getString(STATE_FRAGMENT_EXPLORATION_ID_ARGUMENT_KEY))
 
     subscribeToCurrentState()
 
@@ -171,7 +176,7 @@ class StateFragmentPresenter @Inject constructor(
     ephemeralStateLiveData.observe(fragment, Observer<EphemeralState> { result ->
       itemList.clear()
       currentEphemeralState = result
-
+      checkAndAddContentItem()
       updateDummyStateName()
 
       val interactionId = result.state.interaction.id
@@ -328,6 +333,23 @@ class StateFragmentPresenter @Inject constructor(
       oldStateNameList.add(currentEphemeralState.state.name)
     }
   }
+
+  private fun checkAndAddContentItem() {
+    if (currentEphemeralState.state.hasContent()) {
+      addContentItem()
+    } else {
+      logger.e("StateFragment", "checkAndAddContentItem: State does not have content.")
+    }
+  }
+
+  private fun addContentItem() {
+    val contentViewModel = ContentViewModel()
+    val contentSubtitledHtml: SubtitledHtml = currentEphemeralState.state.content
+    contentViewModel.contentId = contentSubtitledHtml.contentId
+    contentViewModel.htmlContent = contentSubtitledHtml.html
+    itemList.add(contentViewModel)
+    stateAdapter.notifyDataSetChanged()
+  }
 
   private fun updateNavigationButtonVisibility(
     interactionId: String,

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

@@ -0,0 +1,12 @@
+package org.oppia.app.player.state.itemviewmodel
+
+import androidx.lifecycle.ViewModel
+import org.oppia.app.fragment.FragmentScope
+import javax.inject.Inject
+
+/** [ViewModel] for content-card state. */
+@FragmentScope
+class ContentViewModel @Inject constructor() : ViewModel() {
+  var contentId = ""
+  var htmlContent = ""
+}

app/src/main/java/org/oppia/app/testing/ContentCardTestActivity.kt

@@ -0,0 +1,17 @@
+package org.oppia.app.testing
+
+import android.os.Bundle
+import org.oppia.app.activity.InjectableAppCompatActivity
+import javax.inject.Inject
+
+/** Activity to test the functionality of content-card used in [StateFragment]. */
+class ContentCardTestActivity : InjectableAppCompatActivity() {
+  @Inject
+  lateinit var contentCardTestPresenter: ContentCardTestActivityPresenter
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    activityComponent.inject(this)
+    contentCardTestPresenter.handleOnCreate()
+  }
+}

app/src/main/java/org/oppia/app/testing/ContentCardTestActivityPresenter.kt

@@ -0,0 +1,53 @@
+package org.oppia.app.testing
+
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.Observer
+import org.oppia.app.R
+import org.oppia.app.activity.ActivityScope
+import org.oppia.app.player.state.StateFragment
+import org.oppia.domain.exploration.ExplorationDataController
+import org.oppia.domain.exploration.TEST_EXPLORATION_ID_5
+import org.oppia.util.data.AsyncResult
+import org.oppia.util.logging.Logger
+import javax.inject.Inject
+
+private const val EXPLORATION_ID = TEST_EXPLORATION_ID_5
+
+/** The presenter for [ContentCardTestActivity]. */
+@ActivityScope
+class ContentCardTestActivityPresenter @Inject constructor(
+  private val activity: AppCompatActivity,
+  private val explorationDataController: ExplorationDataController,
+  private val logger: Logger
+) {
+  fun handleOnCreate() {
+    activity.setContentView(R.layout.content_card_test_activity)
+    loadDummyExplorationAtStart()
+  }
+
+  private fun getStateFragment(): StateFragment? {
+    return activity.supportFragmentManager.findFragmentById(R.id.state_fragment_placeholder) as StateFragment?
+  }
+
+  private fun loadDummyExplorationAtStart() {
+    explorationDataController.startPlayingExploration(
+      EXPLORATION_ID
+    ).observe(activity, Observer<AsyncResult<Any?>> { result ->
+      when {
+        result.isPending() -> logger.d("ContentCardTest", "Loading exploration")
+        result.isFailure() -> logger.e("ContentCardTest", "Failed to load exploration", result.getErrorOrNull()!!)
+        else -> {
+          logger.d("ContentCardTest", "Successfully loaded exploration")
+
+          if (getStateFragment() == null) {
+            val stateFragment = StateFragment.newInstance(EXPLORATION_ID)
+            activity.supportFragmentManager.beginTransaction().add(
+              R.id.state_fragment_placeholder,
+              stateFragment
+            ).commitNow()
+          }
+        }
+      }
+    })
+  }
+}

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

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:tools="http://schemas.android.com/tools"
+  android:id="@+id/state_fragment_placeholder"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent"
+  tools:context=".testing.ContentCardTestActivity" />

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

@@ -0,0 +1,28 @@
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <data>
+
+    <variable
+      name="htmlContent"
+      type="String" />
+  </data>
+
+  <FrameLayout
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_margin="4dp"
+    android:paddingStart="8dp"
+    android:paddingEnd="8dp">
+
+    <TextView
+      android:id="@+id/content_text_view"
+      android:layout_width="match_parent"
+      android:layout_height="wrap_content"
+      android:layout_margin="4dp"
+      android:background="@drawable/content_blue_background"
+      android:padding="12dp"
+      android:text="@{htmlContent}"
+      android:textColor="@color/oppiaPrimaryText"
+      android:textSize="16sp" />
+  </FrameLayout>
+</layout>

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

@@ -23,6 +23,7 @@ import dagger.Component
 import dagger.Module
 import dagger.Provides
 import kotlinx.coroutines.CoroutineDispatcher
+import org.hamcrest.CoreMatchers.containsString
 import org.hamcrest.CoreMatchers.not
 import org.junit.After
 import org.junit.Before
@@ -35,6 +36,7 @@ import org.oppia.app.player.exploration.ExplorationActivity
 import org.oppia.app.player.state.testing.StateFragmentTestActivity
 import org.oppia.app.recyclerview.RecyclerViewMatcher.Companion.atPosition
 import org.oppia.app.recyclerview.RecyclerViewMatcher.Companion.atPositionOnView
+import org.oppia.app.testing.ContentCardTestActivity
 import org.oppia.util.threading.BackgroundDispatcher
 import org.oppia.util.threading.BlockingDispatcher
 import javax.inject.Singleton
@@ -364,6 +366,16 @@ class StateFragmentTest {
     intended(hasComponent(HomeActivity::class.java.name))
   }
 
+  @Test
+  fun testContentCard_forDemoExploration_withCustomOppiaTags_displaysParsedHtml() {
+    ActivityScenario.launch(ContentCardTestActivity::class.java).use {
+      val htmlResult =
+        "Hi, welcome to Oppia! is a tool that helps you create interactive learning activities that can be continually improved over time.\n\n" +
+            "Incidentally, do you know where the name 'Oppia' comes from?"
+      onView(atPositionOnView(R.id.state_recycler_view, 0,R.id.content_text_view)).check(matches(hasDescendant(withText(htmlResult))))
+    }
+  }
+
   @After
   fun tearDown() {
     Intents.release()

utility/src/main/java/org/oppia/util/parser/ExplorationHtmlParserEntityType.kt

@@ -0,0 +1,7 @@
+package org.oppia.util.parser
+
+import javax.inject.Qualifier
+
+/** Qualifier for injecting the entity type for exploration. */
+@Qualifier
+annotation class ExplorationHtmlParserEntityType