Introduce load exploration part 1

app/src/main/java/org/oppia/app/home/HomeActivity.kt

@@ -2,15 +2,20 @@ package org.oppia.app.home
 
 import android.os.Bundle
 import org.oppia.app.activity.InjectableAppCompatActivity
+import org.oppia.app.player.exploration.ExplorationActivity
 import javax.inject.Inject
 
 /** The central activity for all users entering the app. */
-class HomeActivity : InjectableAppCompatActivity() {
+class HomeActivity : InjectableAppCompatActivity(), RouteToExplorationListener {
   @Inject lateinit var homeActivityController: HomeActivityController
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     activityComponent.inject(this)
     homeActivityController.handleOnCreate()
   }
+
+  override fun routeToExploration() {
+    startActivity(ExplorationActivity.createExplorationActivityIntent(this))
+  }
 }

app/src/main/java/org/oppia/app/home/HomeFragmentController.kt

@@ -1,28 +1,44 @@
 package org.oppia.app.home
 
+import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.Observer
 import org.oppia.app.databinding.HomeFragmentBinding
 import org.oppia.app.fragment.FragmentScope
 import org.oppia.app.viewmodel.ViewModelProvider
 import org.oppia.domain.UserAppHistoryController
+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 TEST_EXPLORATION_ID = TEST_EXPLORATION_ID_5
+
 /** The controller for [HomeFragment]. */
 @FragmentScope
 class HomeFragmentController @Inject constructor(
+  activity: AppCompatActivity,
   private val fragment: Fragment,
   private val viewModelProvider: ViewModelProvider<UserAppHistoryViewModel>,
-  private val userAppHistoryController: UserAppHistoryController
+  private val userAppHistoryController: UserAppHistoryController,
+  private val explorationDataController: ExplorationDataController,
+  private val logger: Logger
 ) {
+
+  private val routeToExplorationListener = activity as RouteToExplorationListener
+
   fun handleCreateView(inflater: LayoutInflater, container: ViewGroup?): View? {
     val binding = HomeFragmentBinding.inflate(inflater, container, /* attachToRoot= */ false)
     // NB: Both the view model and lifecycle owner must be set in order to correctly bind LiveData elements to
     // data-bound view models.
     binding.let {
       it.viewModel = getUserAppHistoryViewModel()
+      it.presenter = this
       it.lifecycleOwner = fragment
     }
 
@@ -34,4 +50,19 @@ class HomeFragmentController @Inject constructor(
   private fun getUserAppHistoryViewModel(): UserAppHistoryViewModel {
     return viewModelProvider.getForFragment(fragment, UserAppHistoryViewModel::class.java)
   }
+
+  fun goToExplorationButtonClicked(v: View) {
+    explorationDataController.startPlayingExploration(
+      TEST_EXPLORATION_ID
+    ).observe(fragment, Observer<AsyncResult<Any?>> { result ->
+      when {
+        result.isPending() -> logger.d("HomeFragmentController", "Loading exploration")
+        result.isFailure() -> logger.e("HomeFragmentController", "Failed to load exploration", result.getErrorOrNull()!!)
+        else -> {
+          logger.d("HomeFragmentController", "Successfully loaded exploration")
+          routeToExplorationListener.routeToExploration()
+        }
+      }
+    })
+  }
 }

app/src/main/java/org/oppia/app/home/RouteToExplorationListener.kt

@@ -0,0 +1,6 @@
+package org.oppia.app.home
+
+/** Listener for when an activity should route to a exploration. */
+interface RouteToExplorationListener {
+  fun routeToExploration()
+}

app/src/main/java/org/oppia/app/player/exploration/ExplorationActivity.kt

@@ -1,16 +1,27 @@
 package org.oppia.app.player.exploration
 
+import android.content.Context
+import android.content.Intent
 import android.os.Bundle
+import android.util.Log
 import org.oppia.app.activity.InjectableAppCompatActivity
 import javax.inject.Inject
 
 /** The starting point for exploration. */
 class ExplorationActivity : InjectableAppCompatActivity() {
-  @Inject lateinit var explorationActivityPresenter: ExplorationActivityPresenter
+  @Inject
+  lateinit var explorationActivityPresenter: ExplorationActivityPresenter
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     activityComponent.inject(this)
     explorationActivityPresenter.handleOnCreate()
   }
+
+  companion object {
+    /** Returns a new [Intent] to route to [ExplorationActivity] for current exploration. */
+    fun createExplorationActivityIntent(context: Context): Intent {
+      return Intent(context, ExplorationActivity::class.java)
+    }
+  }
 }

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

@@ -4,14 +4,19 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
+import androidx.lifecycle.Transformations
 import org.oppia.app.databinding.StateFragmentBinding
 import org.oppia.app.fragment.FragmentScope
 import org.oppia.app.model.CellularDataPreference
+import org.oppia.app.model.EphemeralState
 import org.oppia.app.player.audio.CellularDataDialogFragment
 import org.oppia.app.viewmodel.ViewModelProvider
 import org.oppia.domain.audio.CellularDialogController
+import org.oppia.domain.exploration.ExplorationProgressController
 import org.oppia.util.data.AsyncResult
+import org.oppia.util.logging.Logger
 import javax.inject.Inject
 
 private const val TAG_CELLULAR_DATA_DIALOG = "CELLULAR_DATA_DIALOG"
@@ -21,15 +26,17 @@ private const val TAG_CELLULAR_DATA_DIALOG = "CELLULAR_DATA_DIALOG"
 class StateFragmentPresenter @Inject constructor(
   private val fragment: Fragment,
   private val cellularDialogController: CellularDialogController,
-  private val viewModelProvider: ViewModelProvider<StateViewModel>
+  private val viewModelProvider: ViewModelProvider<StateViewModel>,
+  private val explorationProgressController: ExplorationProgressController,
+  private val logger: Logger
 ) {
 
   private var showCellularDataDialog = true
   private var useCellularData = false
 
   fun handleCreateView(inflater: LayoutInflater, container: ViewGroup?): View? {
     cellularDialogController.getCellularDataPreference()
-      .observe(fragment, Observer<AsyncResult<CellularDataPreference>>{
+      .observe(fragment, Observer<AsyncResult<CellularDataPreference>> {
         if (it.isSuccess()) {
           val prefs = it.getOrDefault(CellularDataPreference.getDefaultInstance())
           showCellularDataDialog = !(prefs.hideDialog)
@@ -42,6 +49,9 @@ class StateFragmentPresenter @Inject constructor(
       it.stateFragment = fragment as StateFragment
       it.viewModel = getStateViewModel()
     }
+
+    subscribeToCurrentState()
+
     return binding.root
   }
 
@@ -81,4 +91,25 @@ class StateFragmentPresenter @Inject constructor(
   fun setAudioFragmentVisible(isVisible: Boolean) {
     getStateViewModel().setAudioFragmentVisible(isVisible)
   }
+
+  private fun subscribeToCurrentState() {
+    ephemeralStateLiveData.observe(fragment, Observer<EphemeralState> { result ->
+      logger.d("StateFragment", "getCurrentState: " + result.state.name)
+    })
+  }
+
+  private val ephemeralStateLiveData: LiveData<EphemeralState> by lazy {
+    getEphemeralState()
+  }
+
+  private fun getEphemeralState(): LiveData<EphemeralState> {
+    return Transformations.map(explorationProgressController.getCurrentState(), ::processCurrentState)
+  }
+
+  private fun processCurrentState(ephemeralStateResult: AsyncResult<EphemeralState>): EphemeralState {
+    if (ephemeralStateResult.isFailure()) {
+      logger.e("StateFragment", "Failed to retrieve ephemeral state", ephemeralStateResult.getErrorOrNull()!!)
+    }
+    return ephemeralStateResult.getOrDefault(EphemeralState.getDefaultInstance())
+  }
 }

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

@@ -6,14 +6,15 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
-    <TextView
-      android:id="@+id/dummy_text_view"
-      android:layout_width="wrap_content"
+    <fragment
+      android:id="@+id/audio_fragment"
+      class="org.oppia.app.player.state.StateFragment"
+      android:layout_width="match_parent"
       android:layout_height="wrap_content"
-      android:text="This is dummy TextView for testing"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
+
   </androidx.constraintlayout.widget.ConstraintLayout>
 </layout>

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

@@ -2,18 +2,18 @@
 <layout
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto">
-
   <data>
     <import type="org.oppia.app.R"/>
     <variable
       name="viewModel"
       type="org.oppia.app.home.UserAppHistoryViewModel"/>
+    <variable
+      name="presenter"
+      type="org.oppia.app.home.HomeFragmentController"/>
   </data>
-
   <androidx.constraintlayout.widget.ConstraintLayout
     android:layout_width="match_parent"
     android:layout_height="match_parent">
-
     <TextView
       android:id="@+id/welcome_text_view"
       android:layout_width="wrap_content"
@@ -23,6 +23,15 @@
       app:layout_constraintLeft_toLeftOf="parent"
       app:layout_constraintRight_toRightOf="parent"
       app:layout_constraintTop_toTopOf="parent"/>
-
+    <Button
+      android:id="@+id/go_to_exploration_button"
+      android:layout_width="wrap_content"
+      android:layout_height="wrap_content"
+      android:layout_marginTop="16dp"
+      android:onClick="@{presenter::goToExplorationButtonClicked}"
+      android:text="Go to exploration"
+      app:layout_constraintEnd_toEndOf="parent"
+      app:layout_constraintStart_toStartOf="parent"
+      app:layout_constraintTop_toBottomOf="@+id/welcome_text_view"/>
   </androidx.constraintlayout.widget.ConstraintLayout>
 </layout>

app/src/sharedTest/java/org/oppia/app/home/HomeActivityTest.kt

@@ -5,6 +5,8 @@ import android.content.Context
 import android.os.Handler
 import android.os.Looper
 import android.view.View
+import androidx.test.espresso.matcher.ViewMatchers.withId
+import androidx.test.espresso.matcher.ViewMatchers.withText
 import androidx.test.core.app.ActivityScenario.launch
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.espresso.Espresso.onIdle
@@ -14,11 +16,10 @@ import androidx.test.espresso.PerformException
 import androidx.test.espresso.UiController
 import androidx.test.espresso.ViewAction
 import androidx.test.espresso.ViewInteraction
+import androidx.test.espresso.action.ViewActions.click
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.idling.CountingIdlingResource
 import androidx.test.espresso.matcher.ViewMatchers.isRoot
-import androidx.test.espresso.matcher.ViewMatchers.withId
-import androidx.test.espresso.matcher.ViewMatchers.withText
 import androidx.test.espresso.util.HumanReadables
 import androidx.test.espresso.util.TreeIterables
 import androidx.test.ext.junit.runners.AndroidJUnit4
@@ -33,7 +34,6 @@ import org.junit.After
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
-import org.oppia.app.R
 import org.oppia.domain.UserAppHistoryController
 import org.oppia.util.logging.EnableConsoleLog
 import org.oppia.util.logging.EnableFileLog
@@ -45,6 +45,7 @@ import java.util.concurrent.AbstractExecutorService
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.TimeoutException
 import javax.inject.Singleton
+import org.oppia.app.R
 
 /** Tests for [HomeActivity]. */
 @RunWith(AndroidJUnit4::class)
@@ -78,6 +79,13 @@ class HomeActivityTest {
     }
   }
 
+  @Test
+  fun testHomeActivity_dummyGoToExplorationButtonClicked_opensExplorationActivity() {
+    launch(HomeActivity::class.java)
+    onView(withId(R.id.go_to_exploration_button)).perform(click())
+    waitForTheView(withId(R.id.dummy_audio_button))
+  }
+
   private fun simulateNewAppInstance() {
     // Simulate a fresh app install by clearing any potential on-disk caches using an isolated app history controller.
     createTestRootComponent().getUserAppHistoryController().clearUserAppHistory()
@@ -192,6 +200,7 @@ class HomeActivityTest {
     interface Builder {
       @BindsInstance
       fun setApplication(application: Application): Builder
+
       fun build(): TestApplicationComponent
     }
 
@@ -207,7 +216,7 @@ class HomeActivityTest {
    * An executor service that schedules all [Runnable]s to run asynchronously on the main thread. This is based on:
    * https://android.googlesource.com/platform/packages/apps/TV/+/android-live-tv/src/com/android/tv/util/MainThreadExecutor.java.
    */
-  private object MainThreadExecutor: AbstractExecutorService() {
+  private object MainThreadExecutor : AbstractExecutorService() {
     override fun isTerminated(): Boolean = false
 
     private val handler = Handler(Looper.getMainLooper())