Fix #4606: Language selector feature implementation

BUILD.bazel

@@ -110,6 +110,7 @@ package_group(
         multidex = apk_flavor_metadata["multidex"],
         deps = [
             "//app/src/main/java/org/oppia/android/app/application/dev:developer_application",
+            "//config/src/java/org/oppia/android/config:all_languages_config",
         ],
     )
     for apk_flavor_metadata in [

app/BUILD.bazel

@@ -769,7 +769,8 @@ kt_android_library(
         ":view_models",
         ":views",
         "//app/src/main/java/org/oppia/android/app/activity:activity_intent_factories_shim",
-        "//app/src/main/java/org/oppia/android/app/activity:injectable_app_compat_activity",
+        "//app/src/main/java/org/oppia/android/app/activity:injectable_auto_localized_app_compat_activity",
+        "//app/src/main/java/org/oppia/android/app/activity:injectable_system_localized_app_compat_activity",
         "//app/src/main/java/org/oppia/android/app/activity/route:activity_router",
         "//app/src/main/java/org/oppia/android/app/fragment:injectable_bottom_sheet_dialog_fragment",
         "//app/src/main/java/org/oppia/android/app/fragment:injectable_dialog_fragment",

app/build.gradle

@@ -98,6 +98,7 @@ def filesToExclude = [
     '**/*AppLanguageLocaleHandlerTest*.kt',
     '**/*AppLanguageResourceHandlerTest*.kt',
     '**/*AppLanguageWatcherMixinTest*.kt',
+    '**/*ActivityLanguageLocaleHandlerTest*.kt'
 ]
 _excludeSourceFiles(filesToExclude)
 

app/src/main/java/org/oppia/android/app/activity/BUILD.bazel

@@ -43,6 +43,20 @@ kt_android_library(
     ],
 )
 
+kt_android_library(
+    name = "injectable_auto_localized_app_compat_activity",
+    srcs = ["InjectableAutoLocalizedAppCompatActivity.kt"],
+    visibility = ["//app:app_visibility"],
+    deps = [":injectable_app_compat_activity"],
+)
+
+kt_android_library(
+    name = "injectable_system_localized_app_compat_activity",
+    srcs = ["InjectableSystemLocalizedAppCompatActivity.kt"],
+    visibility = ["//app:app_visibility"],
+    deps = [":injectable_app_compat_activity"],
+)
+
 kt_android_library(
     name = "activity_component",
     srcs = [

app/src/main/java/org/oppia/android/app/activity/InjectableAppCompatActivity.kt

@@ -11,8 +11,7 @@ import org.oppia.android.app.fragment.FragmentComponentBuilderInjector
 import org.oppia.android.app.fragment.FragmentComponentFactory
 import org.oppia.android.app.translation.AppLanguageActivityInjector
 import org.oppia.android.app.translation.AppLanguageActivityInjectorProvider
-import org.oppia.android.app.translation.AppLanguageApplicationInjectorProvider
-
+import org.oppia.android.app.translation.AppLanguageWatcherMixin
 /**
  * An [AppCompatActivity] that facilitates field injection to child activities and constituent
  * fragments that extend [org.oppia.android.app.fragment.InjectableFragment].
@@ -31,7 +30,7 @@ abstract class InjectableAppCompatActivity :
       "Expected attached Context to have an application context defined."
     }
     onInitializeActivityComponent(applicationContext)
-    val newConfiguration = onInitializeLocalization(applicationContext, newBase)
+    val newConfiguration = onInitializeLocalization(newBase)
     super.attachBaseContext(newBase?.createConfigurationContext(newConfiguration))
   }
 
@@ -58,26 +57,33 @@ abstract class InjectableAppCompatActivity :
   }
 
   private fun onInitializeLocalization(
-    applicationContext: Context,
     newBase: Context?
   ): Configuration {
     // Given how DataProviders work (i.e. by resolving data races using eventual consistency), it's
     // possible to miss some updates in really unlikely situations. No additional work will be done
     // to prevent these data races unless they're actually hit by users. It shouldn't, in practice,
     // be possible since it requires changing the system language between activity transitions, and
     // in most cases that should result in an activity recreation by the mixin, anyway.
-    val appLanguageAppInjectorProvider =
-      applicationContext as AppLanguageApplicationInjectorProvider
-    val appLanguageAppInjector = appLanguageAppInjectorProvider.getAppLanguageApplicationInjector()
-    val appLanguageActivityInjector = activityComponent as AppLanguageActivityInjector
-    val appLanguageLocaleHandler = appLanguageAppInjector.getAppLanguageHandler()
-    val appLanguageWatcherMixin = appLanguageActivityInjector.getAppLanguageWatcherMixin()
-    appLanguageWatcherMixin.initialize()
+    val activityLanguageInjectorProvider = this as AppLanguageActivityInjectorProvider
+    val activityLanguageActivityInjector =
+      activityLanguageInjectorProvider.getAppLanguageActivityInjector()
+    val activityLanguageLocaleHandler =
+      activityLanguageActivityInjector.getActivityLanguageHandler()
+
+    val appLanguageWatcherMixin = activityLanguageActivityInjector.getAppLanguageWatcherMixin()
+    initializeMixin(appLanguageWatcherMixin)
+
     return Configuration(newBase?.resources?.configuration).also { newConfiguration ->
-      appLanguageLocaleHandler.initializeLocaleForActivity(newConfiguration)
+      activityLanguageLocaleHandler.initializeLocaleForActivity(newConfiguration)
     }
   }
 
+  /**
+   * Initializes [appLanguageWatcherMixin] based on the localization requirements of the implementation.
+   * This should never be directly implemented by non-abstract activity classes.
+   */
+  abstract fun initializeMixin(appLanguageWatcherMixin: AppLanguageWatcherMixin)
+
   private fun ensureLayoutDirection() {
     // Ensure the root decor view has the correct layout direct setup per the base context. In some
     // cases, Android will let the app recreate the activity & properly update the layout direction

app/src/main/java/org/oppia/android/app/activity/InjectableAutoLocalizedAppCompatActivity.kt

@@ -0,0 +1,18 @@
+package org.oppia.android.app.activity
+
+import androidx.appcompat.app.AppCompatActivity
+import org.oppia.android.app.translation.AppLanguageWatcherMixin
+
+/**
+ * An [AppCompatActivity] that facilitates field injection to child activities and constituent
+ * fragments that extend [org.oppia.android.app.fragment.InjectableFragment].
+ *
+ * This should be extended by all activities which should be automatically localized based on the
+ * user's selected app language.
+ */
+abstract class InjectableAutoLocalizedAppCompatActivity : InjectableAppCompatActivity() {
+
+  override fun initializeMixin(appLanguageWatcherMixin: AppLanguageWatcherMixin) {
+    appLanguageWatcherMixin.initialize(shouldOnlyUseSystemLanguage = false)
+  }
+}

app/src/main/java/org/oppia/android/app/activity/InjectableSystemLocalizedAppCompatActivity.kt

@@ -0,0 +1,18 @@
+package org.oppia.android.app.activity
+
+import androidx.appcompat.app.AppCompatActivity
+import org.oppia.android.app.translation.AppLanguageWatcherMixin
+
+/**
+ * An [AppCompatActivity] that facilitates field injection to child activities and constituent
+ * fragments that extend [org.oppia.android.app.fragment.InjectableFragment].
+ *
+ * This should be extended by all activities which should be system localized or use the
+ * device default language.
+ */
+abstract class InjectableSystemLocalizedAppCompatActivity : InjectableAppCompatActivity() {
+
+  override fun initializeMixin(appLanguageWatcherMixin: AppLanguageWatcherMixin) {
+    appLanguageWatcherMixin.initialize(shouldOnlyUseSystemLanguage = true)
+  }
+}

app/src/main/java/org/oppia/android/app/administratorcontrols/AdministratorControlsActivity.kt

@@ -5,7 +5,7 @@ import android.content.Intent
 import android.os.Bundle
 import org.oppia.android.R
 import org.oppia.android.app.activity.ActivityComponentImpl
-import org.oppia.android.app.activity.InjectableAppCompatActivity
+import org.oppia.android.app.activity.InjectableAutoLocalizedAppCompatActivity
 import org.oppia.android.app.administratorcontrols.appversion.AppVersionActivity
 import org.oppia.android.app.administratorcontrols.learneranalytics.ProfileAndDeviceIdActivity
 import org.oppia.android.app.drawer.NAVIGATION_PROFILE_ID_ARGUMENT_KEY
@@ -47,7 +47,7 @@ const val PROFILE_AND_DEVICE_ID_FRAGMENT = "PROFILE_AND_DEVICE_ID_FRAGMENT"
 
 /** Activity [AdministratorControlsActivity] that allows user to change admin controls. */
 class AdministratorControlsActivity :
-  InjectableAppCompatActivity(),
+  InjectableAutoLocalizedAppCompatActivity(),
   RouteToProfileListListener,
   RouteToAppVersionListener,
   RouteToLearnerAnalyticsListener,

app/src/main/java/org/oppia/android/app/administratorcontrols/AdministratorControlsFragmentPresenter.kt

@@ -191,11 +191,17 @@ class AdministratorControlsFragmentPresenter @Inject constructor(
   }
 
   private enum class ViewType {
+    /** Represents [View] for the general section. */
     VIEW_TYPE_GENERAL,
+    /** Represents [View] for the profile section. */
     VIEW_TYPE_PROFILE,
+    /** Represents [View] for the download permissions section. */
     VIEW_TYPE_DOWNLOAD_PERMISSIONS,
+    /** Represents [View] for the app information section. */
     VIEW_TYPE_APP_INFORMATION,
+    /** Represents [View] for the account actions section. */
     VIEW_TYPE_ACCOUNT_ACTIONS,
+    /** Represents [View] for the learner analytics section. */
     VIEW_TYPE_LEARNER_ANALYTICS
   }
 }

app/src/main/java/org/oppia/android/app/administratorcontrols/LogoutDialogFragment.kt

@@ -14,8 +14,10 @@ import org.oppia.android.app.profile.ProfileChooserActivity
 class LogoutDialogFragment : InjectableDialogFragment() {
 
   companion object {
+    /** [String] key to access [LogoutDialogFragment]. */
     const val TAG_LOGOUT_DIALOG_FRAGMENT = "TAG_LOGOUT_DIALOG_FRAGMENT"
 
+    /** Returns a new [LogoutDialogFragment] instance. */
     fun newInstance(): LogoutDialogFragment {
       return LogoutDialogFragment()
     }

app/src/main/java/org/oppia/android/app/administratorcontrols/RouteToAppVersionListener.kt

@@ -2,5 +2,6 @@ package org.oppia.android.app.administratorcontrols
 
 /** Listener for when an activity should route to [AppVersionActivity]. */
 interface RouteToAppVersionListener {
+  /** Called when [AppVersionActivity] should be loaded. */
   fun routeToAppVersion()
 }

app/src/main/java/org/oppia/android/app/administratorcontrols/administratorcontrolsitemviewmodel/AdministratorControlsAccountActionsViewModel.kt

@@ -6,7 +6,7 @@ import org.oppia.android.app.administratorcontrols.ShowLogoutDialogListener
 class AdministratorControlsAccountActionsViewModel(
   private val showLogoutDialogListener: ShowLogoutDialogListener
 ) : AdministratorControlsItemViewModel() {
-
+  /** Called when user clicks logout on [AdministratorControlsActivity]. */
   fun onLogOutClicked() {
     showLogoutDialogListener.showLogoutDialog()
   }

app/src/main/java/org/oppia/android/app/administratorcontrols/administratorcontrolsitemviewmodel/AdministratorControlsAppInformationViewModel.kt

@@ -12,6 +12,7 @@ class AdministratorControlsAppInformationViewModel(
   private val routeToAppVersionListener = activity as RouteToAppVersionListener
   private val loadAppVersionListener = activity as LoadAppVersionListener
 
+  /** Called when a user clicks on AppVersion in [AdministratorControlsActivity]. */
   fun onAppVersionClicked() {
     if (isMultipane.get()!!) {
       loadAppVersionListener.loadAppVersion()

app/src/main/java/org/oppia/android/app/administratorcontrols/administratorcontrolsitemviewmodel/AdministratorControlsDownloadPermissionsViewModel.kt

@@ -18,11 +18,16 @@ class AdministratorControlsDownloadPermissionsViewModel(
   private val userProfileId: ProfileId,
   deviceSettings: DeviceSettings
 ) : AdministratorControlsItemViewModel() {
+  /**
+   * [Boolean] observable value showing if topic downloads and updates should happen only on Wifi.
+   */
   val isTopicWifiUpdatePermission =
     ObservableField<Boolean>(deviceSettings.allowDownloadAndUpdateOnlyOnWifi)
+  /** [Boolean] observable value showing if topic updates should happen automatically. */
   val isTopicAutoUpdatePermission =
     ObservableField<Boolean>(deviceSettings.automaticallyUpdateTopics)
 
+  /** Called when topic wifi update permission changes. */
   fun onTopicWifiUpdatePermissionChanged() {
     profileManagementController.updateWifiPermissionDeviceSettings(
       userProfileId,
@@ -42,6 +47,7 @@ class AdministratorControlsDownloadPermissionsViewModel(
       )
   }
 
+  /** Called when topic auto update permission changes. */
   fun onTopicAutoUpdatePermissionChanged() {
     profileManagementController.updateTopicAutomaticallyPermissionDeviceSettings(
       userProfileId,

app/src/main/java/org/oppia/android/app/administratorcontrols/administratorcontrolsitemviewmodel/AdministratorControlsItemViewModel.kt

@@ -3,8 +3,13 @@ package org.oppia.android.app.administratorcontrols.administratorcontrolsitemvie
 import androidx.databinding.ObservableField
 import org.oppia.android.app.viewmodel.ObservableViewModel
 
-/** Super-class for generalising different views for the recyclerView in [AdministratorControlsFragment] */
+/**
+ * Super-class for generalising different views for the recyclerView in
+ * [AdministratorControlsFragment].
+ */
 abstract class AdministratorControlsItemViewModel : ObservableViewModel() {
+  /** [Boolean] observable value showing if [View] is multipane. */
   val isMultipane = ObservableField<Boolean>(false)
+  /** [Int] representing the index of items bound in [AdministratorControlsActivity]. */
   val itemIndex = ObservableField<Int>()
 }

app/src/main/java/org/oppia/android/app/administratorcontrols/administratorcontrolsitemviewmodel/AdministratorControlsProfileViewModel.kt

@@ -9,6 +9,7 @@ class AdministratorControlsProfileViewModel(
   private val loadProfileListListener: LoadProfileListListener
 ) : AdministratorControlsItemViewModel() {
 
+  /** Called when a user clicks on EditProfiles in [AdministratorControlsActivity]. */
   fun onEditProfilesClicked() {
     if (isMultipane.get()!!) {
       loadProfileListListener.loadProfileList()

app/src/main/java/org/oppia/android/app/administratorcontrols/appversion/AppVersionActivity.kt

@@ -5,13 +5,13 @@ import android.content.Intent
 import android.os.Bundle
 import android.view.MenuItem
 import org.oppia.android.app.activity.ActivityComponentImpl
-import org.oppia.android.app.activity.InjectableAppCompatActivity
+import org.oppia.android.app.activity.InjectableAutoLocalizedAppCompatActivity
 import org.oppia.android.app.model.ScreenName.APP_VERSION_ACTIVITY
 import org.oppia.android.util.logging.CurrentAppScreenNameIntentDecorator.decorateWithScreenName
 import javax.inject.Inject
 
 /** Activity for App Version. */
-class AppVersionActivity : InjectableAppCompatActivity() {
+class AppVersionActivity : InjectableAutoLocalizedAppCompatActivity() {
   @Inject
   lateinit var appVersionActivityPresenter: AppVersionActivityPresenter
 
@@ -29,6 +29,7 @@ class AppVersionActivity : InjectableAppCompatActivity() {
   }
 
   companion object {
+    /** Returns an [Intent] to start this activity. */
     fun createAppVersionActivityIntent(context: Context): Intent {
       return Intent(context, AppVersionActivity::class.java).apply {
         decorateWithScreenName(APP_VERSION_ACTIVITY)

app/src/main/java/org/oppia/android/app/administratorcontrols/appversion/AppVersionActivityPresenter.kt

@@ -9,6 +9,8 @@ import javax.inject.Inject
 /** The presenter for [AppVersionActivity]. */
 @ActivityScope
 class AppVersionActivityPresenter @Inject constructor(private val activity: AppCompatActivity) {
+
+  /** Initializes the [AppVersionActivity] views and binds [AppVersionFragment]. */
   fun handleOnCreate() {
     activity.setContentView(R.layout.app_version_activity)
     setToolbar()

app/src/main/java/org/oppia/android/app/administratorcontrols/appversion/AppVersionFragmentPresenter.kt

@@ -17,6 +17,7 @@ class AppVersionFragmentPresenter @Inject constructor(
 ) {
   private lateinit var binding: AppVersionFragmentBinding
 
+  /** Initializes and creates the views for the [AppVersionFragment]. */
   fun handleCreateView(inflater: LayoutInflater, container: ViewGroup?): View? {
     binding = AppVersionFragmentBinding.inflate(
       inflater,

app/src/main/java/org/oppia/android/app/administratorcontrols/appversion/AppVersionViewModel.kt

@@ -10,7 +10,7 @@ import org.oppia.android.app.utility.getVersionName
 import org.oppia.android.app.viewmodel.ObservableViewModel
 import javax.inject.Inject
 
-/** [ViewModel] for [AppVersionFragment]*/
+/** [ViewModel] for [AppVersionFragment]. */
 @FragmentScope
 class AppVersionViewModel @Inject constructor(
   private val resourceHandler: AppLanguageResourceHandler,
@@ -20,9 +20,11 @@ class AppVersionViewModel @Inject constructor(
   private val versionName: String = context.getVersionName()
   private val lastUpdateDateTime = context.getLastUpdateTime()
 
+  /** Returns a localized, human-readable app version name. */
   fun computeVersionNameText(): String =
     resourceHandler.getStringInLocaleWithWrapping(R.string.app_version_name, versionName)
 
+  /** Returns a localized, human-readable lastUpdateDateTime. */
   fun computeLastUpdatedDateText(): String =
     resourceHandler.getStringInLocaleWithWrapping(
       R.string.app_last_update_date, getDateTime(lastUpdateDateTime)

app/src/main/java/org/oppia/android/app/administratorcontrols/learneranalytics/ProfileAndDeviceIdActivity.kt

@@ -5,7 +5,7 @@ import android.content.Intent
 import android.os.Bundle
 import android.view.MenuItem
 import org.oppia.android.app.activity.ActivityComponentImpl
-import org.oppia.android.app.activity.InjectableAppCompatActivity
+import org.oppia.android.app.activity.InjectableAutoLocalizedAppCompatActivity
 import org.oppia.android.app.model.ScreenName.PROFILE_AND_DEVICE_ID_ACTIVITY
 import org.oppia.android.util.logging.CurrentAppScreenNameIntentDecorator.decorateWithScreenName
 import javax.inject.Inject
@@ -17,7 +17,7 @@ import javax.inject.Inject
  * These IDs are meant to help facilitators of app user studies correspond specific logged events to
  * a particular user or group.
  */
-class ProfileAndDeviceIdActivity : InjectableAppCompatActivity() {
+class ProfileAndDeviceIdActivity : InjectableAutoLocalizedAppCompatActivity() {
   @Inject lateinit var profileAndDeviceIdActivityPresenter: ProfileAndDeviceIdActivityPresenter
 
   override fun onCreate(savedInstanceState: Bundle?) {

app/src/main/java/org/oppia/android/app/completedstorylist/CompletedStoryItemViewModel.kt

@@ -16,17 +16,20 @@ class CompletedStoryItemViewModel(
   private val intentFactoryShim: IntentFactoryShim,
   translationController: TranslationController
 ) : ObservableViewModel(), RouteToTopicPlayStoryListener {
+  /** Holds lazily loaded completedStoryName [String] value. */
   val completedStoryName by lazy {
     translationController.extractString(
       completedStory.storyTitle, completedStory.storyWrittenTranslationContext
     )
   }
+  /** Holds lazily loaded topicName [String] value. */
   val topicName by lazy {
     translationController.extractString(
       completedStory.topicTitle, completedStory.topicWrittenTranslationContext
     )
   }
 
+  /** Called when user clicks on CompletedStoryItem. */
   fun onCompletedStoryItemClicked() {
     routeToTopicPlayStory(internalProfileId, completedStory.topicId, completedStory.storyId)
   }

app/src/main/java/org/oppia/android/app/completedstorylist/CompletedStoryListActivity.kt

@@ -4,13 +4,13 @@ import android.content.Context
 import android.content.Intent
 import android.os.Bundle
 import org.oppia.android.app.activity.ActivityComponentImpl
-import org.oppia.android.app.activity.InjectableAppCompatActivity
+import org.oppia.android.app.activity.InjectableAutoLocalizedAppCompatActivity
 import org.oppia.android.app.model.ScreenName.COMPLETED_STORY_LIST_ACTIVITY
 import org.oppia.android.util.logging.CurrentAppScreenNameIntentDecorator.decorateWithScreenName
 import javax.inject.Inject
 
 /** Activity for completed stories. */
-class CompletedStoryListActivity : InjectableAppCompatActivity() {
+class CompletedStoryListActivity : InjectableAutoLocalizedAppCompatActivity() {
   @Inject
   lateinit var completedStoryListActivityPresenter: CompletedStoryListActivityPresenter
 

app/src/main/java/org/oppia/android/app/completedstorylist/CompletedStoryListActivityPresenter.kt

@@ -10,6 +10,8 @@ import javax.inject.Inject
 class CompletedStoryListActivityPresenter @Inject constructor(
   private val activity: AppCompatActivity
 ) {
+
+  /** Initializes views for [CompletedStoryListActivity] and binds [CompletedStoryListFragment]. */
   fun handleOnCreate(internalProfileId: Int) {
     activity.setContentView(R.layout.completed_story_list_activity)
     if (getCompletedStoryListFragment() == null) {