Fix #359: Add descriptions for fractions & ratios topics

app/src/main/java/org/oppia/app/topic/TopicActivity.kt

@@ -17,18 +17,17 @@ const val TOPIC_ACTIVITY_TOPIC_ID_ARGUMENT_KEY = "TopicActivity.topic_id"
 class TopicActivity : InjectableAppCompatActivity(), RouteToQuestionPlayerListener, RouteToConceptCardListener,
   RouteToTopicPlayListener, RouteToStoryListener, RouteToExplorationListener {
   private lateinit var topicId: String
-  private lateinit var storyId: String
+  private var storyId: String? = null
   @Inject
   lateinit var topicActivityPresenter: TopicActivityPresenter
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     activityComponent.inject(this)
-    topicId = checkNotNull(intent?.getStringExtra(org.oppia.app.topic.TOPIC_ACTIVITY_TOPIC_ID_ARGUMENT_KEY) ?: "")
-    {
+    topicId = checkNotNull(intent?.getStringExtra(org.oppia.app.topic.TOPIC_ACTIVITY_TOPIC_ID_ARGUMENT_KEY)) {
       "Expected topic ID to be included in intent for TopicActivity."
     }
-    storyId = intent?.getStringExtra(TOPIC_ACTIVITY_STORY_ID_ARGUMENT_KEY) ?: ""
+    storyId = intent?.getStringExtra(TOPIC_ACTIVITY_STORY_ID_ARGUMENT_KEY)
     topicActivityPresenter.handleOnCreate(topicId, storyId)
   }
 

app/src/main/java/org/oppia/app/topic/TopicActivityPresenter.kt

@@ -14,14 +14,15 @@ const val STORY_ID_ARGUMENT_KEY = "story_id"
 @ActivityScope
 class TopicActivityPresenter @Inject constructor(private val activity: AppCompatActivity) {
 
-  fun handleOnCreate(topicId: String, storyId: String) {
+  fun handleOnCreate(topicId: String, storyId: String?) {
     activity.setContentView(R.layout.topic_activity)
     if (getTopicFragment() == null) {
       val topicFragment = TopicFragment()
       val args = Bundle()
       args.putString(TOPIC_ID_ARGUMENT_KEY, topicId)
-      if (topicId.isNotEmpty() && storyId.isNotEmpty())
+      if (storyId != null) {
         args.putString(STORY_ID_ARGUMENT_KEY, storyId)
+      }
       topicFragment.arguments = args
       activity.supportFragmentManager.beginTransaction().add(
         R.id.topic_fragment_placeholder,

app/src/main/java/org/oppia/app/topic/TopicFragmentPresenter.kt

@@ -60,8 +60,8 @@ class TopicFragmentPresenter @Inject constructor(
     viewPager.setCurrentItem(tab.ordinal, true)
   }
 
-  private fun setUpViewPager(viewPager: ViewPager, topicId: String?) {
-    val adapter = ViewPagerAdapter(fragment.fragmentManager!!, topicId!!, storyId)
+  private fun setUpViewPager(viewPager: ViewPager, topicId: String) {
+    val adapter = ViewPagerAdapter(fragment.childFragmentManager, topicId, storyId)
     viewPager.adapter = adapter
     tabLayout.setupWithViewPager(viewPager)
     tabLayout.getTabAt(0)!!.setText(fragment.getString(R.string.overview)).setIcon(tabIcons[0])

app/src/main/java/org/oppia/app/topic/overview/TopicOverviewFragmentPresenter.kt

@@ -8,6 +8,7 @@ import androidx.fragment.app.Fragment
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
 import androidx.lifecycle.Transformations
+import org.oppia.app.R
 import org.oppia.app.databinding.TopicOverviewFragmentBinding
 import org.oppia.app.fragment.FragmentScope
 import org.oppia.app.model.Topic
@@ -17,6 +18,7 @@ import org.oppia.app.viewmodel.ViewModelProvider
 import org.oppia.domain.topic.TopicController
 import org.oppia.util.data.AsyncResult
 import org.oppia.util.logging.Logger
+import org.oppia.util.parser.HtmlParser
 import javax.inject.Inject
 
 /** The presenter for [TopicOverviewFragment]. */
@@ -26,11 +28,15 @@ class TopicOverviewFragmentPresenter @Inject constructor(
   private val fragment: Fragment,
   private val viewModelProvider: ViewModelProvider<TopicOverviewViewModel>,
   private val logger: Logger,
-  private val topicController: TopicController
+  private val topicController: TopicController,
+  private val htmlParserFactory: HtmlParser.Factory
 ) {
   private val routeToTopicPlayListener = activity as RouteToTopicPlayListener
   private val topicOverviewViewModel = getTopicOverviewViewModel()
   private lateinit var topicId: String
+  private val htmlParser: HtmlParser by lazy {
+    htmlParserFactory.create(/* entityType= */ "topic", topicId)
+  }
 
   fun handleCreateView(inflater: LayoutInflater, container: ViewGroup?): View? {
     topicId = checkNotNull(fragment.arguments?.getString(TOPIC_ID_ARGUMENT_KEY)) {
@@ -46,7 +52,7 @@ class TopicOverviewFragmentPresenter @Inject constructor(
     return binding.root
   }
 
-  fun seeMoreClicked(v: View) {
+  fun seeMoreClicked(@Suppress("UNUSED_PARAMETER") v: View) {
     routeToTopicPlayListener.routeToTopicPlayFragment()
   }
 
@@ -57,8 +63,14 @@ class TopicOverviewFragmentPresenter @Inject constructor(
   private val topicLiveData: LiveData<Topic> by lazy { getTopicList() }
 
   private fun subscribeToTopicLiveData() {
-    topicLiveData.observe(fragment, Observer<Topic> { result ->
-      topicOverviewViewModel.topic.set(result)
+    topicLiveData.observe(fragment, Observer<Topic> { topic ->
+      topicOverviewViewModel.topic.set(topic)
+      topicOverviewViewModel.topicDescription.set(
+        htmlParser.parseOppiaHtml(
+          topic.description,
+          fragment.requireView().findViewById(R.id.topic_description_text_view)
+        )
+      )
     })
   }
 

app/src/main/java/org/oppia/app/topic/overview/TopicOverviewViewModel.kt

@@ -13,5 +13,7 @@ import javax.inject.Inject
 class TopicOverviewViewModel @Inject constructor() : ObservableViewModel() {
   val topic = ObservableField<Topic>(Topic.getDefaultInstance())
 
+  val topicDescription = ObservableField<CharSequence>("")
+
   var downloadStatusIndicatorDrawableResourceId = ObservableField<Int>(R.drawable.ic_available_offline_primary_24dp)
 }

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

@@ -83,7 +83,7 @@
         android:layout_marginTop="16dp"
         android:layout_marginEnd="24dp"
         android:gravity="start"
-        android:text="@{viewModel.topic.description}"
+        android:text="@{viewModel.topicDescription}"
         android:textColor="@color/oppiaPrimaryText"
         android:textSize="16sp"
         app:layout_constraintEnd_toEndOf="parent"

app/src/sharedTest/java/org/oppia/app/topic/overview/TopicOverviewFragmentTest.kt

@@ -1,116 +1,92 @@
 package org.oppia.app.topic.overview
 
-import android.app.Application
-import android.content.Context
 import android.content.pm.ActivityInfo
+import android.text.SpannedString
+import android.text.style.StyleSpan
+import android.widget.TextView
 import androidx.test.core.app.ActivityScenario
+import androidx.test.core.app.ApplicationProvider
 import androidx.test.espresso.Espresso.onView
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.matcher.ViewMatchers.isClickable
 import androidx.test.espresso.matcher.ViewMatchers.withId
 import androidx.test.espresso.matcher.ViewMatchers.withText
 import androidx.test.ext.junit.runners.AndroidJUnit4
-import androidx.test.rule.ActivityTestRule
-import dagger.BindsInstance
-import dagger.Component
-import dagger.Module
-import dagger.Provides
-import kotlinx.coroutines.CoroutineDispatcher
+import com.google.common.truth.Truth.assertThat
 import org.hamcrest.Matchers.containsString
-import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.oppia.app.R
 import org.oppia.app.topic.TopicActivity
 import org.oppia.app.utility.EspressoTestsMatchers.withDrawable
-import org.oppia.util.threading.BackgroundDispatcher
-import org.oppia.util.threading.BlockingDispatcher
-import javax.inject.Singleton
 
+private const val TEST_TOPIC_ID = "GJ2rLXRKD5hw"
+private const val TOPIC_NAME = "Fractions"
+private const val TOPIC_DESCRIPTION =
+  "You'll often need to talk about part of an object or group. For example, a jar of milk might be half-full, or " +
+      "some of the eggs in a box might have broken. In these lessons, you'll learn to use fractions to describe " +
+      "situations like these."
+
+// NOTE TO DEVELOPERS: this test must be annotated with @LooperMode(LooperMode.MODE.PAUSED) to pass.
 /** Tests for [TopicOverviewFragment]. */
 @RunWith(AndroidJUnit4::class)
 class TopicOverviewFragmentTest {
-
-  private val topicThumbnail = R.drawable.lesson_thumbnail_graphic_child_with_cupcakes
-
-  private val topicName = "Second Test Topic"
-
-  private val topicDescription =
-    "A topic considering the various implications of having especially long topic descriptions. " +
-        "These descriptions almost certainly need to wrap, which should be interesting in the UI (especially on " +
-        "small screens). Consider also that there may even be multiple points pertaining to a topic, some of which " +
-        "may require expanding the description section in order to read the whole topic description."
-
-  @get:Rule
-  var activityTestRule: ActivityTestRule<TopicActivity> = ActivityTestRule(
-    TopicActivity::class.java, /* initialTouchMode= */ true, /* launchActivity= */ false
-  )
+  private val topicThumbnail = R.drawable.lesson_thumbnail_graphic_child_with_fractions_homework
 
   @Test
   fun testTopicOverviewFragment_loadFragment_checkTopicName_isCorrect() {
-    ActivityScenario.launch(TopicActivity::class.java).use {
-      onView(withId(R.id.topic_name_text_view)).check(matches(withText(containsString(topicName))))
+    launchTopicActivityIntent(TEST_TOPIC_ID).use {
+      onView(withId(R.id.topic_name_text_view)).check(matches(withText(containsString(TOPIC_NAME))))
     }
   }
 
   // TODO(#135): Update this test case to check on click of See More play tab is shown.
   @Test
   fun testTopicOverviewFragment_loadFragment_seeMoreIsClickable() {
-    ActivityScenario.launch(TopicActivity::class.java).use {
+    launchTopicActivityIntent(TEST_TOPIC_ID).use {
       onView(withId(R.id.see_more_text_view)).check(matches(isClickable()))
     }
   }
 
   @Test
   fun testTopicOverviewFragment_loadFragmentWithTestTopicId1_checkTopicDescription_isCorrect() {
-    ActivityScenario.launch(TopicActivity::class.java).use {
-      onView(withId(R.id.topic_description_text_view)).check(matches(withText(containsString(topicDescription))))
+    launchTopicActivityIntent(TEST_TOPIC_ID).use {
+      onView(withId(R.id.topic_description_text_view)).check(matches(withText(containsString(TOPIC_DESCRIPTION))))
+    }
+  }
+
+  @Test
+  fun testTopicOverviewFragment_loadFragmentWithTestTopicId1_checkTopicDescription_hasRichText() {
+    launchTopicActivityIntent(TEST_TOPIC_ID).use { scenario ->
+      scenario.onActivity { activity ->
+        val descriptionTextView: TextView = activity.findViewById(R.id.topic_description_text_view)
+        val descriptionText = descriptionTextView.text as SpannedString
+        val spans = descriptionText.getSpans(0, descriptionText.length, StyleSpan::class.java)
+        assertThat(spans).isNotEmpty()
+      }
     }
   }
 
   @Test
   fun testTopicOverviewFragment_loadFragment_configurationChange_checkTopicThumbnail_isCorrect() {
-    ActivityScenario.launch(TopicActivity::class.java).use {
+    launchTopicActivityIntent(TEST_TOPIC_ID).use {
       onView(withId(R.id.topic_thumbnail_image_view)).check(matches(withDrawable(topicThumbnail)))
     }
   }
 
   @Test
   fun testTopicOverviewFragment_loadFragment_configurationChange_checkTopicName_isCorrect() {
-    activityTestRule.launchActivity(null)
-    activityTestRule.activity.requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE
-    onView(withId(R.id.topic_name_text_view)).check(matches(withText(containsString(topicName))))
-  }
+    launchTopicActivityIntent(TEST_TOPIC_ID).use { scenario ->
+      scenario.onActivity {  activity ->
+        activity.requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE
+      }
 
-  @Module
-  class TestModule {
-    @Provides
-    @Singleton
-    fun provideContext(application: Application): Context {
-      return application
-    }
-
-    // TODO(#89): Introduce a proper IdlingResource for background dispatchers to ensure they all complete before
-    //  proceeding in an Espresso test. This solution should also be interoperative with Robolectric contexts by using a
-    //  test coroutine dispatcher.
-
-    @Singleton
-    @Provides
-    @BackgroundDispatcher
-    fun provideBackgroundDispatcher(@BlockingDispatcher blockingDispatcher: CoroutineDispatcher): CoroutineDispatcher {
-      return blockingDispatcher
+      onView(withId(R.id.topic_name_text_view)).check(matches(withText(containsString(TOPIC_NAME))))
     }
   }
 
-  @Singleton
-  @Component(modules = [TestModule::class])
-  interface TestApplicationComponent {
-    @Component.Builder
-    interface Builder {
-      @BindsInstance
-      fun setApplication(application: Application): Builder
-
-      fun build(): TestApplicationComponent
-    }
+  private fun launchTopicActivityIntent(topicId: String): ActivityScenario<TopicActivity> {
+    val intent = TopicActivity.createTopicActivityIntent(ApplicationProvider.getApplicationContext(), topicId)
+    return ActivityScenario.launch(intent)
   }
 }

domain/src/main/assets/fractions_topic.json

@@ -1,7 +1,7 @@
 {
   "topic": {
     "story_reference_schema_version": 1,
-    "description": "",
+    "description": "You'll often need to talk about <b>part</b> of an object or group. For example, a jar of milk might be half-full, or some of the eggs in a box might have broken. In these lessons, you'll learn to use <b>fractions</b> to describe situations like these.",
     "canonical_story_references": [
       {
         "story_id": "wANbh4oOClga",

domain/src/main/assets/ratios_topic.json

@@ -1,7 +1,7 @@
 {
   "topic": {
     "story_reference_schema_version": 1,
-    "description": "",
+    "description": "Many everyday problems involve thinking about proportions. For example, if 30 apples cost 6 dollars, how much would 12 apples cost? In these lessons, you'll learn about how to use ratios and proportional reasoning to solve problems like this.",
     "canonical_story_references": [],
     "language_code": "en",
     "id": "omzF4oqgeTXd",