feat: Add language settings (#2913)

app/build.gradle.kts

@@ -149,7 +149,6 @@ android {
         debug {
             applicationIdSuffix = ".debug"
             resValue("string", "app_name", "ReVanced Manager (Debug)")
-            isPseudoLocalesEnabled = true
 
             buildConfigField("long", "BUILD_ID", "${Random.nextLong()}L")
         }
@@ -243,6 +242,8 @@ android {
             version = "3.22.1"
         }
     }
+
+    sourceSets["main"].kotlin.srcDir(layout.buildDirectory.dir("generated/source/locales"))
 }
 
 kotlin {
@@ -250,6 +251,47 @@ kotlin {
 }
 
 tasks {
+    val generateSupportedLocales by registering {
+        description = "Generate list of supported locales from resource directories"
+
+        val resDir = file("src/main/res")
+        val outputDir = layout.buildDirectory.dir("generated/source/locales")
+
+        inputs.dir(resDir)
+        outputs.dir(outputDir)
+
+        doLast {
+            val locales = resDir.listFiles()
+                .orEmpty()
+                .filter { it.isDirectory && it.name.matches(Regex("values-[a-z]{2}(-r[A-Z]{2})?")) }
+                .map { it.name.removePrefix("values-").replace("-r", "-") }
+                .sorted()
+                .joinToString(",\n        ") { "Locale.forLanguageTag(\"$it\")" }
+
+            val output = outputDir.get().asFile.resolve("app/revanced/manager/util/GeneratedLocales.kt")
+            output.parentFile.mkdirs()
+            output.writeText(
+                """
+                |package app.revanced.manager.util
+                |
+                |import java.util.Locale
+                |
+                |object GeneratedLocales {
+                |    val SUPPORTED_LOCALES = listOf(
+                |        Locale.ENGLISH,
+                |        $locales,
+                |    )
+                |}
+                """.trimMargin()
+            )
+        }
+    }
+
+    preBuild {
+        dependsOn(generateSupportedLocales)
+    }
+
+
     // Needed by gradle-semantic-release-plugin.
     // Tracking: https://github.com/KengoTODA/gradle-semantic-release-plugin/issues/435.
     val publish by registering {

app/src/main/java/app/revanced/manager/MainActivity.kt

@@ -3,11 +3,11 @@ package app.revanced.manager
 import android.content.ActivityNotFoundException
 import android.os.Bundle
 import android.os.Parcelable
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.animation.ExperimentalAnimationApi
 import androidx.compose.animation.slideInHorizontally
 import androidx.compose.animation.slideOutHorizontally
@@ -63,7 +63,7 @@ import org.koin.androidx.compose.navigation.koinNavViewModel
 import org.koin.core.parameter.parametersOf
 import org.koin.androidx.viewmodel.ext.android.getViewModel as getActivityViewModel
 
-class MainActivity : ComponentActivity() {
+class MainActivity : AppCompatActivity() {
     @ExperimentalAnimationApi
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)

app/src/main/java/app/revanced/manager/ui/screen/settings/GeneralSettingsScreen.kt

@@ -8,6 +8,8 @@ import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.FilledTonalButton
@@ -19,6 +21,7 @@ import androidx.compose.material3.rememberTopAppBarState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
@@ -38,6 +41,7 @@ import app.revanced.manager.ui.theme.Theme
 import app.revanced.manager.ui.viewmodel.GeneralSettingsViewModel
 import org.koin.androidx.compose.koinViewModel
 import org.koin.compose.koinInject
+import java.util.Locale
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -48,6 +52,7 @@ fun GeneralSettingsScreen(
     val prefs = viewModel.prefs
     val coroutineScope = viewModel.viewModelScope
     var showThemePicker by rememberSaveable { mutableStateOf(false) }
+    var showLanguagePicker by rememberSaveable { mutableStateOf(false) }
 
     if (showThemePicker) {
         ThemePicker(
@@ -55,6 +60,17 @@ fun GeneralSettingsScreen(
             onConfirm = { viewModel.setTheme(it) }
         )
     }
+
+    if (showLanguagePicker) {
+        LanguagePicker(
+            supportedLocales = viewModel.getSupportedLocales(),
+            currentLocale = viewModel.getCurrentLocale(),
+            onDismiss = { showLanguagePicker = false },
+            onConfirm = { viewModel.setLocale(it) },
+            getDisplayName = { viewModel.getLocaleDisplayName(it) }
+        )
+    }
+
     val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior(rememberTopAppBarState())
 
     Scaffold(
@@ -74,6 +90,24 @@ fun GeneralSettingsScreen(
         ) {
             GroupHeader(stringResource(R.string.appearance))
 
+            val currentLocale = viewModel.getCurrentLocale()
+            val currentLanguageDisplay = remember(currentLocale) {
+                currentLocale?.let { viewModel.getLocaleDisplayName(it) }
+            }
+            SettingsListItem(
+                modifier = Modifier.clickable { showLanguagePicker = true },
+                headlineContent = stringResource(R.string.language),
+                supportingContent = stringResource(R.string.language_description),
+                trailingContent = {
+                    FilledTonalButton(onClick = { showLanguagePicker = true }) {
+                        Text(
+                            currentLanguageDisplay
+                                ?: stringResource(R.string.language_system_default)
+                        )
+                    }
+                }
+            )
+
             val theme by prefs.theme.getAsState()
             SettingsListItem(
                 modifier = Modifier.clickable { showThemePicker = true },
@@ -156,4 +190,64 @@ private fun ThemePicker(
             }
         }
     )
+}
+
+@Composable
+private fun LanguagePicker(
+    supportedLocales: List<Locale>,
+    currentLocale: Locale?,
+    onDismiss: () -> Unit,
+    onConfirm: (Locale?) -> Unit,
+    getDisplayName: (Locale) -> String
+) {
+    var selectedLocale by remember { mutableStateOf(currentLocale) }
+    val systemDefaultString = stringResource(R.string.language_system_default)
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringResource(R.string.language)) },
+        text = {
+            Column(
+                modifier = Modifier.verticalScroll(rememberScrollState())
+            ) {
+                Row(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .clickable { selectedLocale = null },
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    HapticRadioButton(
+                        selected = selectedLocale == null,
+                        onClick = { selectedLocale = null }
+                    )
+                    Text(systemDefaultString)
+                }
+
+                supportedLocales.forEach { locale ->
+                    Row(
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .clickable { selectedLocale = locale },
+                        verticalAlignment = Alignment.CenterVertically
+                    ) {
+                        HapticRadioButton(
+                            selected = selectedLocale == locale,
+                            onClick = { selectedLocale = locale }
+                        )
+                        Text(getDisplayName(locale))
+                    }
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    onConfirm(selectedLocale)
+                    onDismiss()
+                }
+            ) {
+                Text(stringResource(R.string.apply))
+            }
+        }
+    )
 }

app/src/main/java/app/revanced/manager/ui/viewmodel/GeneralSettingsViewModel.kt

@@ -1,17 +1,26 @@
 package app.revanced.manager.ui.viewmodel
 
+import android.app.Application
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import app.revanced.manager.domain.manager.PreferencesManager
 import app.revanced.manager.ui.theme.Theme
+import app.revanced.manager.util.SupportedLocales
 import app.revanced.manager.util.resetListItemColorsCached
 import kotlinx.coroutines.launch
+import java.util.Locale
 
 class GeneralSettingsViewModel(
+    private val app: Application,
     val prefs: PreferencesManager
 ) : ViewModel() {
     fun setTheme(theme: Theme) = viewModelScope.launch {
         prefs.theme.update(theme)
         resetListItemColorsCached()
     }
+
+    fun getSupportedLocales() = SupportedLocales.getSupportedLocales(app)
+    fun getCurrentLocale() = SupportedLocales.getCurrentLocale()
+    fun setLocale(locale: Locale?) = SupportedLocales.setLocale(locale)
+    fun getLocaleDisplayName(locale: Locale) = SupportedLocales.getDisplayName(locale)
 }

app/src/main/java/app/revanced/manager/util/SupportedLocales.kt

@@ -0,0 +1,32 @@
+package app.revanced.manager.util
+
+import android.content.Context
+import android.os.Build
+import android.os.LocaleList
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.core.os.LocaleListCompat
+import java.util.Locale
+
+object SupportedLocales {
+    fun getSupportedLocales(context: Context): List<Locale> {
+        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            runCatching {
+                android.app.LocaleConfig(context).supportedLocales?.toList()
+            }.getOrNull() ?: GeneratedLocales.SUPPORTED_LOCALES
+        } else {
+            GeneratedLocales.SUPPORTED_LOCALES
+        }
+    }
+
+    fun getCurrentLocale(): Locale? =
+        AppCompatDelegate.getApplicationLocales().takeIf { !it.isEmpty }?.get(0)
+
+    fun setLocale(locale: Locale?) = AppCompatDelegate.setApplicationLocales(
+        locale?.let { LocaleListCompat.create(it) } ?: LocaleListCompat.getEmptyLocaleList()
+    )
+
+    fun getDisplayName(locale: Locale) =
+        locale.getDisplayName(locale).replaceFirstChar { it.uppercase(locale) }
+
+    private fun LocaleList.toList() = (0 until size()).map { get(it) }
+}

app/src/main/res/values/strings.xml

@@ -83,7 +83,7 @@ Second \"item\" text"</string>
     <string name="auto_updates_dialog_note">These settings can be changed later.</string>
 
     <string name="general">General</string>
-    <string name="general_description">Theme, dynamic color</string>
+    <string name="general_description">Language, theme, dynamic color</string>
     <string name="updates">Updates</string>
     <string name="updates_description">Check for updates and view changelogs</string>
     <string name="downloads">Downloads</string>
@@ -104,6 +104,9 @@ Second \"item\" text"</string>
     <string name="pure_black_theme_description">Use pure black backgrounds for dark theme</string>
     <string name="theme">Theme</string>
     <string name="theme_description">Choose between light or dark theme</string>
+    <string name="language">Language</string>
+    <string name="language_description">Choose the app display language</string>
+    <string name="language_system_default">System default</string>
     <string name="safeguards">Safeguards</string>
     <string name="patch_compat_check">Disable version compatibility check</string>
     <string name="patch_compat_check_description">Do not restrict patches to compatible app versions</string>