Fixes #5039: Force LTR alignment for Terms of Service & Privacy Policy in RTL languages

app/BUILD.bazel

@@ -639,6 +639,7 @@ kt_android_library(
         "//:dagger",
         "//app/src/main/java/org/oppia/android/app/activity:activity_intent_factories_shim",
         "//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_english_only_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/activity/BUILD.bazel

@@ -49,14 +49,30 @@ kt_android_library(
     name = "injectable_auto_localized_app_compat_activity",
     srcs = ["InjectableAutoLocalizedAppCompatActivity.kt"],
     visibility = ["//app:app_visibility"],
-    deps = [":injectable_app_compat_activity"],
+    deps = [
+        ":injectable_app_compat_activity",
+        "//model/src/main/proto:languages_java_proto_lite",
+    ],
 )
 
 kt_android_library(
     name = "injectable_system_localized_app_compat_activity",
     srcs = ["InjectableSystemLocalizedAppCompatActivity.kt"],
     visibility = ["//app:app_visibility"],
-    deps = [":injectable_app_compat_activity"],
+    deps = [
+        ":injectable_app_compat_activity",
+        "//model/src/main/proto:languages_java_proto_lite",
+    ],
+)
+
+kt_android_library(
+    name = "injectable_english_only_app_compat_activity",
+    srcs = ["InjectableEnglishOnlyAppCompatActivity.kt"],
+    visibility = ["//app:app_visibility"],
+    deps = [
+        ":injectable_app_compat_activity",
+        "//model/src/main/proto:languages_java_proto_lite",
+    ],
 )
 
 kt_android_library(

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

@@ -1,6 +1,7 @@
 package org.oppia.android.app.activity
 
 import androidx.appcompat.app.AppCompatActivity
+import org.oppia.android.app.model.ForcedActivityLanguageMode
 import org.oppia.android.app.translation.AppLanguageWatcherMixin
 
 /**
@@ -13,6 +14,6 @@ import org.oppia.android.app.translation.AppLanguageWatcherMixin
 abstract class InjectableAutoLocalizedAppCompatActivity : InjectableAppCompatActivity() {
 
   override fun initializeMixin(appLanguageWatcherMixin: AppLanguageWatcherMixin) {
-    appLanguageWatcherMixin.initialize(shouldOnlyUseSystemLanguage = false)
+    appLanguageWatcherMixin.initialize(ForcedActivityLanguageMode.USE_APP_LANGUAGE)
   }
 }

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

@@ -0,0 +1,20 @@
+package org.oppia.android.app.activity
+
+import androidx.appcompat.app.AppCompatActivity
+import org.oppia.android.app.model.ForcedActivityLanguageMode
+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 activities which should always display in English regardless of the
+ * user's selected app or system language (e.g. policies pages which show canonical English
+ * content).
+ */
+abstract class InjectableEnglishOnlyAppCompatActivity : InjectableAppCompatActivity() {
+
+  override fun initializeMixin(appLanguageWatcherMixin: AppLanguageWatcherMixin) {
+    appLanguageWatcherMixin.initialize(ForcedActivityLanguageMode.USE_ENGLISH)
+  }
+}

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

@@ -1,6 +1,7 @@
 package org.oppia.android.app.activity
 
 import androidx.appcompat.app.AppCompatActivity
+import org.oppia.android.app.model.ForcedActivityLanguageMode
 import org.oppia.android.app.translation.AppLanguageWatcherMixin
 
 /**
@@ -13,6 +14,6 @@ import org.oppia.android.app.translation.AppLanguageWatcherMixin
 abstract class InjectableSystemLocalizedAppCompatActivity : InjectableAppCompatActivity() {
 
   override fun initializeMixin(appLanguageWatcherMixin: AppLanguageWatcherMixin) {
-    appLanguageWatcherMixin.initialize(shouldOnlyUseSystemLanguage = true)
+    appLanguageWatcherMixin.initialize(ForcedActivityLanguageMode.USE_SYSTEM_LANGUAGE)
   }
 }

app/src/main/java/org/oppia/android/app/policies/PoliciesActivity.kt

@@ -4,7 +4,7 @@ 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.InjectableAutoLocalizedAppCompatActivity
+import org.oppia.android.app.activity.InjectableEnglishOnlyAppCompatActivity
 import org.oppia.android.app.model.PoliciesActivityParams
 import org.oppia.android.app.model.PolicyPage
 import org.oppia.android.app.model.ScreenName.POLICIES_ACTIVITY
@@ -15,7 +15,7 @@ import javax.inject.Inject
 
 /** Activity for displaying the app policies. */
 class PoliciesActivity :
-  InjectableAutoLocalizedAppCompatActivity(),
+  InjectableEnglishOnlyAppCompatActivity(),
   RouteToPoliciesListener {
 
   @Inject

app/src/main/java/org/oppia/android/app/policies/PoliciesFragmentPresenter.kt

@@ -1,6 +1,7 @@
 package org.oppia.android.app.policies
 
 import android.os.Bundle
+import android.view.Gravity
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -44,6 +45,15 @@ class PoliciesFragmentPresenter @Inject constructor(
       scrollPosition = it.getInt(KEY_SCROLL_Y, 0)
     }
 
+    // Policy content is always in English, so force LTR layout direction and left gravity
+    // to ensure proper alignment of all content including list items (<li> tags) even when
+    // the app is set to an RTL language.
+    binding.policyDescriptionTextView.apply {
+      layoutDirection = View.LAYOUT_DIRECTION_LTR
+      textDirection = View.TEXT_DIRECTION_LTR
+      gravity = Gravity.START
+    }
+
     setUpContentForTextViews(policiesFragmentArguments.policyPage, binding)
 
     (binding.root as ScrollView).viewTreeObserver.addOnGlobalLayoutListener {

app/src/main/java/org/oppia/android/app/translation/AppLanguageWatcherMixin.kt

@@ -2,6 +2,7 @@ package org.oppia.android.app.translation
 
 import androidx.appcompat.app.AppCompatActivity
 import androidx.lifecycle.Observer
+import org.oppia.android.app.model.ForcedActivityLanguageMode
 import org.oppia.android.domain.locale.LocaleController
 import org.oppia.android.domain.oppialogger.OppiaLogger
 import org.oppia.android.domain.profile.ProfileManagementController
@@ -37,9 +38,10 @@ class AppLanguageWatcherMixin @Inject constructor(
    * called before interacting with the locale handler to avoid inadvertent crashes in such
    * situations.
    *
-   * @param shouldOnlyUseSystemLanguage whether only the system language should be used
+   * @param forcedActivityLanguageMode the [ForcedActivityLanguageMode] indicating how the locale
+   *     should be resolved for this activity
    */
-  fun initialize(shouldOnlyUseSystemLanguage: Boolean) {
+  fun initialize(forcedActivityLanguageMode: ForcedActivityLanguageMode) {
     if (!appLanguageLocaleHandler.isInitialized()) {
       /* The handler might have been de-initialized since bootstrapping. This can generally happen
        * in two cases:
@@ -68,10 +70,27 @@ class AppLanguageWatcherMixin @Inject constructor(
 
     val currentUserProfileId = profileManagementController.getCurrentProfileId()
 
-    val activityLanguageLocaleDataProvider = when {
-      shouldOnlyUseSystemLanguage -> translationController.getSystemLanguageLocale()
-      currentUserProfileId == null -> translationController.getSystemLanguageLocale()
-      else -> translationController.getAppLanguageLocale(currentUserProfileId)
+    val activityLanguageLocaleDataProvider = when (forcedActivityLanguageMode) {
+      ForcedActivityLanguageMode.USE_SYSTEM_LANGUAGE ->
+        translationController.getSystemLanguageLocale()
+      ForcedActivityLanguageMode.USE_ENGLISH ->
+        translationController.getEnglishLocale()
+      ForcedActivityLanguageMode.USE_APP_LANGUAGE -> {
+        if (currentUserProfileId == null) {
+          translationController.getSystemLanguageLocale()
+        } else {
+          translationController.getAppLanguageLocale(currentUserProfileId)
+        }
+      }
+      ForcedActivityLanguageMode.FORCED_ACTIVITY_LANGUAGE_MODE_UNSPECIFIED,
+      ForcedActivityLanguageMode.UNRECOGNIZED -> {
+        oppiaLogger.w(
+          "AppLanguageWatcherMixin",
+          "Unexpected ForcedActivityLanguageMode: $forcedActivityLanguageMode. " +
+            "Falling back to system language."
+        )
+        translationController.getSystemLanguageLocale()
+      }
     }
 
     val liveData = activityLanguageLocaleDataProvider.toLiveData()

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

@@ -62,6 +62,7 @@ kt_android_library(
         ":app_language_locale_handler",
         "//domain/src/main/java/org/oppia/android/domain/profile:profile_management_controller",
         "//domain/src/main/java/org/oppia/android/domain/translation:translation_controller",
+        "//model/src/main/proto:languages_java_proto_lite",
     ],
 )
 

app/src/test/java/org/oppia/android/app/translation/AppLanguageWatcherMixinTest.kt

@@ -28,6 +28,7 @@ import org.oppia.android.app.application.testing.TestingBuildFlavorModule
 import org.oppia.android.app.devoptions.DeveloperOptionsModule
 import org.oppia.android.app.devoptions.DeveloperOptionsStarterModule
 import org.oppia.android.app.model.AppLanguageSelection
+import org.oppia.android.app.model.ForcedActivityLanguageMode
 import org.oppia.android.app.model.LegacyProfileId
 import org.oppia.android.app.model.OppiaLanguage
 import org.oppia.android.app.model.OppiaLanguage.BRAZILIAN_PORTUGUESE
@@ -146,7 +147,7 @@ class AppLanguageWatcherMixinTest {
   fun testMixin_initialized_noAppLanguageChange_doesNothing() {
     profileTestHelper.initializeProfiles()
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = false)
+      mixin.initialize(ForcedActivityLanguageMode.USE_APP_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       // Initializing without anything changing should result in no changes to the locale or activity.
@@ -160,7 +161,7 @@ class AppLanguageWatcherMixinTest {
   fun testMixin_initialized_withAppLanguageChange_sameLanguage_localeIsUnchanged() {
     profileTestHelper.initializeProfiles()
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = false)
+      mixin.initialize(ForcedActivityLanguageMode.USE_APP_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       updateAppLanguageTo(ENGLISH)
@@ -175,7 +176,7 @@ class AppLanguageWatcherMixinTest {
   fun testMixin_initialized_withAppLanguageChange_newLanguage_updatesLocale() {
     profileTestHelper.initializeProfiles()
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = false)
+      mixin.initialize(ForcedActivityLanguageMode.USE_APP_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       updateAppLanguageTo(BRAZILIAN_PORTUGUESE)
@@ -190,7 +191,7 @@ class AppLanguageWatcherMixinTest {
   fun testMixin_initialized_withAppLanguageChange_sameLanguage_doesNotRecreateActivity() {
     profileTestHelper.initializeProfiles()
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = false)
+      mixin.initialize(ForcedActivityLanguageMode.USE_APP_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       updateAppLanguageTo(ENGLISH)
@@ -204,7 +205,7 @@ class AppLanguageWatcherMixinTest {
   fun testMixin_initialized_withAppLanguageChange_newLanguage_recreatesActivity() {
     profileTestHelper.initializeProfiles()
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = false)
+      mixin.initialize(ForcedActivityLanguageMode.USE_APP_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       updateAppLanguageTo(BRAZILIAN_PORTUGUESE)
@@ -218,7 +219,7 @@ class AppLanguageWatcherMixinTest {
   fun testMixin_initialized_withShouldUseSystemLanguage_initializesSystemLanguage() {
     profileTestHelper.initializeProfiles()
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = true)
+      mixin.initialize(ForcedActivityLanguageMode.USE_SYSTEM_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       updateAppLanguageTo(BRAZILIAN_PORTUGUESE)
@@ -230,10 +231,41 @@ class AppLanguageWatcherMixinTest {
     }
   }
 
+  @Test
+  fun testMixin_initialized_withShouldUseEnglish_initializesEnglishAndIgnoresAppLanguageChanges() {
+    profileTestHelper.initializeProfiles()
+    runAlongsideTestActivity { mixin ->
+      mixin.initialize(ForcedActivityLanguageMode.USE_ENGLISH)
+      testCoroutineDispatchers.runCurrent()
+
+      updateAppLanguageTo(BRAZILIAN_PORTUGUESE)
+
+      // English should remain the selected locale even when app language is changed.
+      val localeContext = appLanguageLocaleHandler.getDisplayLocale().localeContext
+      assertThat(localeContext.languageDefinition.language).isEqualTo(ENGLISH)
+      assertThat(testActivityRecreator.getRecreateCount()).isEqualTo(0)
+    }
+  }
+
+  @Test
+  fun testMixin_initialized_withUnspecifiedMode_fallsBackToSystemLanguage() {
+    profileTestHelper.initializeProfiles()
+    runAlongsideTestActivity { mixin ->
+      mixin.initialize(ForcedActivityLanguageMode.FORCED_ACTIVITY_LANGUAGE_MODE_UNSPECIFIED)
+      testCoroutineDispatchers.runCurrent()
+
+      updateAppLanguageTo(BRAZILIAN_PORTUGUESE)
+
+      // Unspecified mode should deterministically fall back to system language.
+      val localeContext = appLanguageLocaleHandler.getDisplayLocale().localeContext
+      assertThat(localeContext.languageDefinition.language).isEqualTo(ENGLISH)
+    }
+  }
+
   @Test
   fun testMixin_initialized_noProfileLoggedIn_initializesSystemLanguage() {
     runAlongsideTestActivity { mixin ->
-      mixin.initialize(shouldOnlyUseSystemLanguage = true)
+      mixin.initialize(ForcedActivityLanguageMode.USE_SYSTEM_LANGUAGE)
       testCoroutineDispatchers.runCurrent()
 
       updateAppLanguageTo(BRAZILIAN_PORTUGUESE)

domain/src/main/java/org/oppia/android/domain/translation/TranslationController.kt

@@ -98,6 +98,17 @@ class TranslationController @Inject constructor(
     }
   }
 
+  /**
+   * Returns a data provider for an app string [OppiaLocale.DisplayLocale] corresponding to the
+   * English language.
+   *
+   * This is used for activities that should always display in English regardless of the user's
+   * selected app language (e.g. the policies pages which show canonical English content).
+   */
+  fun getEnglishLocale(): DataProvider<OppiaLocale.DisplayLocale> {
+    return localeController.retrieveAppStringDisplayLocale(OppiaLanguage.ENGLISH)
+  }
+
   /**
    * Returns a data provider for the current [OppiaLanguage] selected for app strings for the
    * specified user (per their [profileId]).

model/src/main/proto/languages.proto

@@ -37,6 +37,25 @@ enum OppiaLanguage {
   NIGERIAN_PIDGIN = 8;
 }
 
+// Defines the forced language mode for an activity, determining how its locale is resolved.
+// This is used to specify whether an activity should follow the user's app language, the system
+// language, or always use English (e.g. for policies pages whose content is canonical English).
+enum ForcedActivityLanguageMode {
+  // Default value; unspecified mode. This should not be used in practice.
+  FORCED_ACTIVITY_LANGUAGE_MODE_UNSPECIFIED = 0;
+
+  // Use the user's selected app language (or system default if none is selected).
+  USE_APP_LANGUAGE = 1;
+
+  // Use the system's default language, ignoring the user's app language selection.
+  USE_SYSTEM_LANGUAGE = 2;
+
+  // Force English locale, regardless of system or app language settings.
+  // Used for activities displaying canonical English content such as Terms of Service
+  // and Privacy Policy.
+  USE_ENGLISH = 3;
+}
+
 // The list of regions explicitly supported natively by the Android app. Note that the app is not
 // automatically unsupported in countries not on this list. Countries absent from this list may
 // default to default system behavior for certain localization situations (such as date & time

scripts/assets/file_content_validation_checks.textproto

@@ -206,9 +206,10 @@ file_content_checks {
 file_content_checks {
   file_path_regex: ".+?\\.kt"
   prohibited_content_regex: "\\sInjectableAppCompatActivity\\("
-  failure_message: "Never subclass InjectableAppCompatActivity directly. Instead, use InjectableSystemLocalizedAppCompatActivity or InjectableAutoLocalizedAppCompatActivity."
+  failure_message: "Never subclass InjectableAppCompatActivity directly. Instead, use InjectableSystemLocalizedAppCompatActivity, InjectableAutoLocalizedAppCompatActivity, or InjectableEnglishOnlyAppCompatActivity."
   exempted_file_name: "app/src/main/java/org/oppia/android/app/activity/InjectableSystemLocalizedAppCompatActivity.kt"
   exempted_file_name: "app/src/main/java/org/oppia/android/app/activity/InjectableAutoLocalizedAppCompatActivity.kt"
+  exempted_file_name: "app/src/main/java/org/oppia/android/app/activity/InjectableEnglishOnlyAppCompatActivity.kt"
   exempted_file_name: "scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt"
 }
 file_content_checks {
@@ -435,6 +436,7 @@ file_content_checks {
   exempted_file_name:"app/src/main/java/org/oppia/android/app/activity/InjectableAppCompatActivity.kt"
   exempted_file_name: "app/src/main/java/org/oppia/android/app/activity/InjectableAutoLocalizedAppCompatActivity.kt"
   exempted_file_name: "app/src/main/java/org/oppia/android/app/activity/InjectableSystemLocalizedAppCompatActivity.kt"
+  exempted_file_name: "app/src/main/java/org/oppia/android/app/activity/InjectableEnglishOnlyAppCompatActivity.kt"
   exempted_file_patterns: "app/src/main/java/org/oppia/android/app/testing.+?\\.kt"
   exempted_file_patterns: "app/src/main/java/org/oppia/android/app/devoptions/testing.+?\\.kt"
   exempted_file_patterns: "app/src/main/java/org/oppia/android/app/devoptions/vieweventlogs/testing.+?\\.kt"

scripts/assets/test_file_exemptions.textproto

@@ -38,6 +38,10 @@ test_file_exemption {
   exempted_file_path: "app/src/main/java/org/oppia/android/app/activity/InjectableAutoLocalizedAppCompatActivity.kt"
   test_file_not_required: true
 }
+test_file_exemption {
+  exempted_file_path: "app/src/main/java/org/oppia/android/app/activity/InjectableEnglishOnlyAppCompatActivity.kt"
+  test_file_not_required: true
+}
 test_file_exemption {
   exempted_file_path: "app/src/main/java/org/oppia/android/app/activity/InjectableSystemLocalizedAppCompatActivity.kt"
   test_file_not_required: true

scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt

@@ -103,7 +103,8 @@ class RegexPatternValidationCheckTest {
     "Never subclass AppCompatActivity directly. Instead, use InjectableAppCompatActivity."
   private val subclassedInjectableAppCompatActivityErrorMessage =
     "Never subclass InjectableAppCompatActivity directly. Instead, use " +
-      "InjectableSystemLocalizedAppCompatActivity or InjectableAutoLocalizedAppCompatActivity."
+      "InjectableSystemLocalizedAppCompatActivity, InjectableAutoLocalizedAppCompatActivity, " +
+      "or InjectableEnglishOnlyAppCompatActivity."
   private val subclassedDialogFragmentErrorMessage =
     "DialogFragment should never be subclassed. Use InjectableDialogFragment, instead."
   private val androidActivityConfigChangesErrorMessage =