Fix part of #3600: Add tablet UI for FAQs and Third-party Dependencies

app/BUILD.bazel

@@ -67,6 +67,8 @@ LISTENERS = [
     "src/main/java/org/oppia/android/app/devoptions/RouteToMarkTopicsCompletedListener.kt",
     "src/main/java/org/oppia/android/app/devoptions/RouteToViewEventLogsListener.kt",
     "src/main/java/org/oppia/android/app/drawer/RouteToProfileProgressListener.kt",
+    "src/main/java/org/oppia/android/app/help/LoadFAQListFragmentListener.kt",
+    "src/main/java/org/oppia/android/app/help/LoadThirdPartyDependencyListFragmentListener.kt",
     "src/main/java/org/oppia/android/app/help/RouteToFAQListListener.kt",
     "src/main/java/org/oppia/android/app/help/RouteToThirdPartyDependencyListListener.kt",
     "src/main/java/org/oppia/android/app/help/faq/RouteToFAQSingleListener.kt",
@@ -138,6 +140,7 @@ DATABINDING_LAYOUTS = ["src/main/res/layout*/**"]
 VIEW_MODELS_WITH_RESOURCE_IMPORTS = [
     "src/main/java/org/oppia/android/app/help/HelpItemViewModel.kt",
     "src/main/java/org/oppia/android/app/help/HelpListViewModel.kt",
+    "src/main/java/org/oppia/android/app/help/HelpViewModel.kt",
     "src/main/java/org/oppia/android/app/help/faq/FAQListViewModel.kt",
     "src/main/java/org/oppia/android/app/help/thirdparty/LicenseListViewModel.kt",
     "src/main/java/org/oppia/android/app/help/thirdparty/LicenseTextViewModel.kt",

app/src/main/java/org/oppia/android/app/help/HelpActivity.kt

@@ -3,30 +3,56 @@ package org.oppia.android.app.help
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
+import android.widget.TextView
 import org.oppia.android.R
 import org.oppia.android.app.activity.InjectableAppCompatActivity
 import org.oppia.android.app.drawer.NAVIGATION_PROFILE_ID_ARGUMENT_KEY
 import org.oppia.android.app.help.faq.FAQListActivity
+import org.oppia.android.app.help.faq.RouteToFAQSingleListener
+import org.oppia.android.app.help.faq.faqsingle.FAQSingleActivity
+import org.oppia.android.app.help.thirdparty.LicenseListActivity
+import org.oppia.android.app.help.thirdparty.LicenseTextViewerActivity
+import org.oppia.android.app.help.thirdparty.RouteToLicenseListListener
+import org.oppia.android.app.help.thirdparty.RouteToLicenseTextListener
 import org.oppia.android.app.help.thirdparty.ThirdPartyDependencyListActivity
 import javax.inject.Inject
 
+private const val HELP_OPTIONS_TITLE_SAVED_KEY = "HelpActivity.help_options_title"
+private const val SELECTED_FRAGMENT_SAVED_KEY = "HelpActivity.selected_fragment"
+const val FAQ_LIST_FRAGMENT_TAG = "FAQListFragment.tag"
+const val THIRD_PARTY_DEPENDENCY_LIST_FRAGMENT_TAG = "ThirdPartyDependencyListFragment.tag"
+
 /** The help page activity for FAQs and third-party dependencies. */
 class HelpActivity :
   InjectableAppCompatActivity(),
   RouteToFAQListListener,
-  RouteToThirdPartyDependencyListListener {
+  RouteToFAQSingleListener,
+  RouteToThirdPartyDependencyListListener,
+  RouteToLicenseTextListener,
+  RouteToLicenseListListener,
+  LoadFAQListFragmentListener,
+  LoadThirdPartyDependencyListFragmentListener {
 
   @Inject
   lateinit var helpActivityPresenter: HelpActivityPresenter
 
+  private lateinit var selectedFragment: String
+
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
     activityComponent.inject(this)
     val isFromNavigationDrawer = intent.getBooleanExtra(
       BOOL_IS_FROM_NAVIGATION_DRAWER_EXTRA_KEY,
       /* defaultValue= */ false
     )
-    helpActivityPresenter.handleOnCreate(isFromNavigationDrawer)
+    selectedFragment =
+      savedInstanceState?.getString(SELECTED_FRAGMENT_SAVED_KEY) ?: FAQ_LIST_FRAGMENT_TAG
+    val extraHelpOptionsTitle = savedInstanceState?.getString(HELP_OPTIONS_TITLE_SAVED_KEY)
+    helpActivityPresenter.handleOnCreate(
+      extraHelpOptionsTitle,
+      isFromNavigationDrawer,
+      selectedFragment
+    )
     title = getString(R.string.menu_help)
   }
 
@@ -56,4 +82,47 @@ class HelpActivity :
     val intent = ThirdPartyDependencyListActivity.createThirdPartyDependencyListActivityIntent(this)
     startActivity(intent)
   }
+
+  override fun loadFAQListFragment() {
+    selectedFragment = FAQ_LIST_FRAGMENT_TAG
+    helpActivityPresenter.handleLoadFAQListFragment()
+  }
+
+  override fun loadThirdPartyDependencyListFragment() {
+    selectedFragment = THIRD_PARTY_DEPENDENCY_LIST_FRAGMENT_TAG
+    helpActivityPresenter.handleLoadThirdPartyDependencyListFragment()
+  }
+
+  override fun onSaveInstanceState(outState: Bundle) {
+    super.onSaveInstanceState(outState)
+    val titleTextView = findViewById<TextView>(R.id.help_multipane_options_title_textview)
+    if (titleTextView != null) {
+      outState.putString(HELP_OPTIONS_TITLE_SAVED_KEY, titleTextView.text.toString())
+    }
+    outState.putString(SELECTED_FRAGMENT_SAVED_KEY, selectedFragment)
+  }
+
+  override fun onRouteToLicenseText(dependencyIndex: Int, licenseIndex: Int) {
+    startActivity(
+      LicenseTextViewerActivity.createLicenseTextViewerActivityIntent(
+        this,
+        dependencyIndex,
+        licenseIndex
+      )
+    )
+  }
+
+  override fun onRouteToLicenseList(dependencyIndex: Int) {
+    startActivity(
+      LicenseListActivity
+        .createLicenseListActivityIntent(
+          context = this,
+          dependencyIndex = dependencyIndex
+        )
+    )
+  }
+
+  override fun onRouteToFAQSingle(question: String, answer: String) {
+    startActivity(FAQSingleActivity.createFAQSingleActivityIntent(this, question, answer))
+  }
 }

app/src/main/java/org/oppia/android/app/help/HelpActivityPresenter.kt

@@ -1,12 +1,17 @@
 package org.oppia.android.app.help
 
 import android.view.View
+import android.widget.FrameLayout
+import android.widget.TextView
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.widget.Toolbar
 import androidx.drawerlayout.widget.DrawerLayout
+import androidx.fragment.app.Fragment
 import org.oppia.android.R
 import org.oppia.android.app.activity.ActivityScope
 import org.oppia.android.app.drawer.NavigationDrawerFragment
+import org.oppia.android.app.help.faq.FAQListFragment
+import org.oppia.android.app.help.thirdparty.ThirdPartyDependencyListFragment
 import javax.inject.Inject
 
 /** The presenter for [HelpActivity]. */
@@ -15,7 +20,11 @@ class HelpActivityPresenter @Inject constructor(private val activity: AppCompatA
   private lateinit var navigationDrawerFragment: NavigationDrawerFragment
   private lateinit var toolbar: Toolbar
 
-  fun handleOnCreate(isFromNavigationDrawer: Boolean) {
+  fun handleOnCreate(
+    extraHelpOptionsTitle: String?,
+    isFromNavigationDrawer: Boolean,
+    selectedFragment: String
+  ) {
     if (isFromNavigationDrawer) {
       activity.setContentView(R.layout.help_activity)
       setUpToolbar()
@@ -28,12 +37,53 @@ class HelpActivityPresenter @Inject constructor(private val activity: AppCompatA
         activity.finish()
       }
     }
-    if (getHelpFragment() == null) {
-      activity.supportFragmentManager.beginTransaction().add(
-        R.id.help_fragment_placeholder,
-        HelpFragment()
-      ).commitNow()
+    val titleTextView =
+      activity.findViewById<TextView>(R.id.options_activity_selected_options_title)
+    if (titleTextView != null) {
+      setMultipaneContainerTitle(extraHelpOptionsTitle!!)
     }
+    val isMultipane = activity.findViewById<FrameLayout>(R.id.multipane_options_container) != null
+    if (isMultipane) {
+      loadMultipaneFragment(selectedFragment)
+    }
+    val previousFragment = getHelpFragment()
+    if (previousFragment != null) {
+      activity.supportFragmentManager.beginTransaction().remove(previousFragment).commitNow()
+    }
+    activity.supportFragmentManager.beginTransaction().add(
+      R.id.help_fragment_placeholder,
+      HelpFragment.newInstance(isMultipane)
+    ).commitNow()
+  }
+
+  /** Loads [ThirdPartyDependencyListFragment] in tablet devices. */
+  fun handleLoadThirdPartyDependencyListFragment() {
+    setMultipaneContainerTitle(
+      activity.getString(R.string.third_party_dependency_list_activity_title)
+    )
+    getMultipaneOptionsFragment()?.let {
+      activity.supportFragmentManager.beginTransaction().remove(
+        it
+      ).commit()
+    }
+    val thirdPartyDependencyListFragment = ThirdPartyDependencyListFragment.newInstance()
+    activity.supportFragmentManager.beginTransaction().add(
+      R.id.multipane_options_container,
+      thirdPartyDependencyListFragment
+    ).commitNow()
+  }
+
+  /** Loads [FAQListFragment] in tablet devices. */
+  fun handleLoadFAQListFragment() {
+    setMultipaneContainerTitle(activity.getString(R.string.faq_activity_title))
+    getMultipaneOptionsFragment()?.let {
+      activity.supportFragmentManager.beginTransaction().remove(it)
+        .commit()
+    }
+    activity.supportFragmentManager.beginTransaction().add(
+      R.id.multipane_options_container,
+      FAQListFragment()
+    ).commitNow()
   }
 
   private fun setUpToolbar() {
@@ -59,4 +109,19 @@ class HelpActivityPresenter @Inject constructor(private val activity: AppCompatA
       .supportFragmentManager
       .findFragmentById(R.id.help_fragment_placeholder) as HelpFragment?
   }
+
+  private fun loadMultipaneFragment(selectedFragment: String) {
+    when (selectedFragment) {
+      FAQ_LIST_FRAGMENT_TAG -> handleLoadFAQListFragment()
+      THIRD_PARTY_DEPENDENCY_LIST_FRAGMENT_TAG -> handleLoadThirdPartyDependencyListFragment()
+    }
+  }
+
+  private fun setMultipaneContainerTitle(title: String) {
+    activity.findViewById<TextView>(R.id.help_multipane_options_title_textview).text = title
+  }
+
+  private fun getMultipaneOptionsFragment(): Fragment? {
+    return activity.supportFragmentManager.findFragmentById(R.id.multipane_options_container)
+  }
 }

app/src/main/java/org/oppia/android/app/help/HelpFragment.kt

@@ -8,11 +8,24 @@ import android.view.ViewGroup
 import org.oppia.android.app.fragment.InjectableFragment
 import javax.inject.Inject
 
+private const val IS_MULTIPANE_KEY = "HelpFragment.bool_is_multipane"
+
 /** Fragment that contains help in the app. */
 class HelpFragment : InjectableFragment() {
   @Inject
   lateinit var helpFragmentPresenter: HelpFragmentPresenter
 
+  companion object {
+    /** Returns instance of [HelpFragment]. */
+    fun newInstance(isMultipane: Boolean): HelpFragment {
+      val args = Bundle()
+      args.putBoolean(IS_MULTIPANE_KEY, isMultipane)
+      val fragment = HelpFragment()
+      fragment.arguments = args
+      return fragment
+    }
+  }
+
   override fun onAttach(context: Context) {
     super.onAttach(context)
     fragmentComponent.inject(this)
@@ -23,6 +36,10 @@ class HelpFragment : InjectableFragment() {
     container: ViewGroup?,
     savedInstanceState: Bundle?
   ): View? {
-    return helpFragmentPresenter.handleCreateView(inflater, container)
+    val args = checkNotNull(arguments) {
+      "Expected arguments to be passed to HelpFragment"
+    }
+    val isMultipane = args.getBoolean(IS_MULTIPANE_KEY)
+    return helpFragmentPresenter.handleCreateView(inflater, container, isMultipane)
   }
 }

app/src/main/java/org/oppia/android/app/help/HelpFragmentPresenter.kt

@@ -22,8 +22,13 @@ class HelpFragmentPresenter @Inject constructor(
 ) {
   private lateinit var binding: HelpFragmentBinding
 
-  fun handleCreateView(inflater: LayoutInflater, container: ViewGroup?): View? {
+  fun handleCreateView(
+    inflater: LayoutInflater,
+    container: ViewGroup?,
+    isMultipane: Boolean
+  ): View? {
     val viewModel = getHelpListViewModel()
+    viewModel.isMultipane.set(isMultipane)
 
     binding = HelpFragmentBinding.inflate(
       inflater,

app/src/main/java/org/oppia/android/app/help/HelpItemViewModel.kt

@@ -7,18 +7,30 @@ import org.oppia.android.app.viewmodel.ObservableViewModel
 /** [ObservableViewModel] for the recycler view of HelpActivity. */
 class HelpItemViewModel(
   val activity: AppCompatActivity,
-  val title: String
+  val title: String,
+  val isMultipane: Boolean
 ) : ObservableViewModel() {
   fun onClick(title: String) {
     when (title) {
       activity.getString(R.string.frequently_asked_questions_FAQ) -> {
-        val routeToFAQListener = activity as RouteToFAQListListener
-        routeToFAQListener.onRouteToFAQList()
+        if (isMultipane) {
+          val loadFAQListFragmentListener = activity as LoadFAQListFragmentListener
+          loadFAQListFragmentListener.loadFAQListFragment()
+        } else {
+          val routeToFAQListener = activity as RouteToFAQListListener
+          routeToFAQListener.onRouteToFAQList()
+        }
       }
       activity.getString(R.string.third_party_dependency_list_activity_title) -> {
-        val routeToThirdPartyDependencyListListener = activity
-          as RouteToThirdPartyDependencyListListener
-        routeToThirdPartyDependencyListListener.onRouteToThirdPartyDependencyList()
+        if (isMultipane) {
+          val loadThirdPartyDependencyListFragmentListener = activity as
+            LoadThirdPartyDependencyListFragmentListener
+          loadThirdPartyDependencyListFragmentListener.loadThirdPartyDependencyListFragment()
+        } else {
+          val routeToThirdPartyDependencyListListener = activity
+            as RouteToThirdPartyDependencyListListener
+          routeToThirdPartyDependencyListListener.onRouteToThirdPartyDependencyList()
+        }
       }
     }
   }

app/src/main/java/org/oppia/android/app/help/HelpListViewModel.kt

@@ -2,13 +2,12 @@ package org.oppia.android.app.help
 
 import androidx.appcompat.app.AppCompatActivity
 import org.oppia.android.R
-import org.oppia.android.app.viewmodel.ObservableViewModel
 import javax.inject.Inject
 
 /** View model in [HelpFragment]. */
 class HelpListViewModel @Inject constructor(
   val activity: AppCompatActivity
-) : ObservableViewModel() {
+) : HelpViewModel() {
   private val arrayList = ArrayList<HelpItemViewModel>()
 
   val helpItemList: List<HelpItemViewModel> by lazy {
@@ -22,11 +21,11 @@ class HelpListViewModel @Inject constructor(
       when (item) {
         HelpItems.FAQ -> {
           category = activity.getString(R.string.frequently_asked_questions_FAQ)
-          helpItemViewModel = HelpItemViewModel(activity, category)
+          helpItemViewModel = HelpItemViewModel(activity, category, isMultipane.get()!!)
         }
         HelpItems.THIRD_PARTY -> {
           category = activity.getString(R.string.third_party_dependency_list_activity_title)
-          helpItemViewModel = HelpItemViewModel(activity, category)
+          helpItemViewModel = HelpItemViewModel(activity, category, isMultipane.get()!!)
         }
       }
       arrayList.add(helpItemViewModel)

app/src/main/java/org/oppia/android/app/help/HelpViewModel.kt

@@ -0,0 +1,10 @@
+package org.oppia.android.app.help
+
+import androidx.databinding.ObservableField
+import org.oppia.android.app.viewmodel.ObservableViewModel
+
+/** Option items view model for the recyclerView in [HelpFragment] */
+abstract class HelpViewModel : ObservableViewModel() {
+  /** Determines whether the device in use has a large screen. */
+  val isMultipane = ObservableField<Boolean>(false)
+}

app/src/main/java/org/oppia/android/app/help/LoadFAQListFragmentListener.kt

@@ -0,0 +1,7 @@
+package org.oppia.android.app.help
+
+/** Listener for when a selection should result to [FAQListFragment] in tablet devices. */
+interface LoadFAQListFragmentListener {
+  /** Starts [FAQListFragment] in tablet devices. */
+  fun loadFAQListFragment()
+}

app/src/main/java/org/oppia/android/app/help/LoadThirdPartyDependencyListFragmentListener.kt

@@ -0,0 +1,10 @@
+package org.oppia.android.app.help
+
+/**
+ * Listener for when a selection should result to [ThirdPartyDependencyListFragment] in tablet
+ * devices.
+ */
+interface LoadThirdPartyDependencyListFragmentListener {
+  /** Starts [ThirdPartyDependencyListFragment] in tablet devices. */
+  fun loadThirdPartyDependencyListFragment()
+}

app/src/main/res/drawable/ic_arrow_back_black_24_dp.xml

@@ -0,0 +1,11 @@
+<vector
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  android:width="24dp"
+  android:height="24dp"
+  android:viewportWidth="24.0"
+  android:autoMirrored="true"
+  android:viewportHeight="24.0">
+  <path
+    android:fillColor="#333333"
+    android:pathData="M20,11H7.83l5.59,-5.59L12,4l-8,8 8,8 1.41,-1.41L7.83,13H20v-2z"/>
+</vector>