Add an option to change in-app language

closes #77

app/build.gradle.kts

@@ -117,6 +117,7 @@ dependencies {
     implementation(libs.com.github.sadellie.themmo)
     implementation(libs.com.google.accompanist.systemuicontroller)
     implementation(libs.androidx.datastore)
+    implementation(libs.androidx.appcompat)
 
     implementation(project(mapOf("path" to ":feature:converter")))
     implementation(project(mapOf("path" to ":feature:calculator")))

app/src/main/AndroidManifest.xml

@@ -7,8 +7,8 @@
         android:name=".UnittoApplication"
         android:icon="@mipmap/ic_launcher_icon"
         android:label="@string/calculator"
-
         android:supportsRtl="false"
+        android:localeConfig="@xml/locales_config"
         android:theme="@style/Theme.Unitto">
         <activity
             android:windowSoftInputMode="adjustPan"
@@ -36,6 +36,15 @@
                 <action android:name="android.service.quicksettings.action.QS_TILE" />
             </intent-filter>
         </service>
+
+        <service
+            android:name="androidx.appcompat.app.AppLocalesMetadataHolderService"
+            android:enabled="false"
+            android:exported="false">
+            <meta-data
+                android:name="autoStoreLocales"
+                android:value="true" />
+        </service>
 </application>
 
 </manifest>

app/src/main/java/com/sadellie/unitto/MainActivity.kt

@@ -23,8 +23,8 @@ import android.content.Context
 import android.os.Bundle
 import android.util.AttributeSet
 import android.view.View
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.appcompat.app.AppCompatActivity
 import androidx.core.view.WindowCompat
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.sadellie.unitto.data.userprefs.UserPreferencesRepository
@@ -32,7 +32,7 @@ import dagger.hilt.android.AndroidEntryPoint
 import javax.inject.Inject
 
 @AndroidEntryPoint
-internal class MainActivity : ComponentActivity() {
+internal class MainActivity : AppCompatActivity() {
 
     @Inject
     lateinit var userPrefsRepository: UserPreferencesRepository

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

@@ -1,5 +1,5 @@
 <resources>
-    <style name="Theme.Unitto" parent="@android:style/Theme.Material.NoActionBar">
+    <style name="Theme.Unitto" parent="Theme.AppCompat.DayNight.NoActionBar">
         <item name="android:windowBackground">@color/window_background</item>
         <item name="android:statusBarColor">@color/window_background</item>
         <item name="android:navigationBarColor">@color/window_background</item>

core/base/src/main/res/values/strings.xml

@@ -1382,4 +1382,13 @@ Used in this dialog window. Should be short -->
     <string name="add">Add</string>
     <string name="subtract">Subtract</string>
     <string name="date_calculator">Date calculator</string>
+
+    <string name="locale_en" translatable="false">English</string>
+    <string name="locale_de" translatable="false">Deutsch</string>
+    <string name="locale_en_rGB" translatable="false">English (UK)</string>
+    <string name="locale_fr" translatable="false">Français</string>
+    <string name="locale_it" translatable="false">Italiano</string>
+    <string name="locale_ru" translatable="false">Русский</string>
+    <string name="language_setting">Language</string>
+    <string name="language_setting_support">Change the app language</string>
 </resources>

core/base/src/main/res/xml/locales_config.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Unitto is a unit converter for Android
+  ~ Copyright (c) 2023 Elshan Agaev
+  ~
+  ~ This program is free software: you can redistribute it and/or modify
+  ~ it under the terms of the GNU General Public License as published by
+  ~ the Free Software Foundation, either version 3 of the License, or
+  ~ (at your option) any later version.
+  ~
+  ~ This program is distributed in the hope that it will be useful,
+  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
+  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  ~ GNU General Public License for more details.
+  ~
+  ~ You should have received a copy of the GNU General Public License
+  ~ along with this program.  If not, see <https://www.gnu.org/licenses/>.
+  -->
+
+<locale-config xmlns:android="http://schemas.android.com/apk/res/android">
+    <locale android:name="en"/>
+    <locale android:name="de"/>
+    <locale android:name="en-rGB"/>
+    <locale android:name="fr"/>
+    <locale android:name="it"/>
+    <locale android:name="ru"/>
+</locale-config>

feature/settings/build.gradle.kts

@@ -30,6 +30,7 @@ android {
 dependencies {
     implementation(libs.com.github.sadellie.themmo)
     implementation(libs.org.burnoutcrew.composereorderable)
+    implementation(libs.androidx.appcompat)
 
     implementation(project(mapOf("path" to ":data:common")))
     implementation(project(mapOf("path" to ":data:model")))

feature/settings/src/main/java/com/sadellie/unitto/feature/settings/SettingsScreen.kt

@@ -18,12 +18,14 @@
 
 package com.sadellie.unitto.feature.settings
 
+import androidx.appcompat.app.AppCompatDelegate
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ExposureZero
 import androidx.compose.material.icons.filled.Home
 import androidx.compose.material.icons.filled.Info
+import androidx.compose.material.icons.filled.Language
 import androidx.compose.material.icons.filled.Palette
 import androidx.compose.material.icons.filled.RateReview
 import androidx.compose.material.icons.filled.Rule
@@ -42,6 +44,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
+import androidx.core.os.LocaleListCompat
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.sadellie.unitto.core.base.BuildConfig
@@ -63,7 +66,7 @@ import com.sadellie.unitto.feature.settings.navigation.unitsGroupRoute
 internal fun SettingsScreen(
     viewModel: SettingsViewModel = hiltViewModel(),
     menuButtonClick: () -> Unit,
-    navControllerAction: (String) -> Unit
+    navControllerAction: (String) -> Unit,
 ) {
     val mContext = LocalContext.current
     val userPrefs = viewModel.userPrefs.collectAsStateWithLifecycle()
@@ -206,6 +209,21 @@ internal fun SettingsScreen(
                 )
             }
 
+            // LANGUAGE
+            item {
+                ListItem(
+                    leadingContent = {
+                        Icon(
+                            Icons.Default.Language,
+                            stringResource(R.string.language_setting)
+                        )
+                    },
+                    headlineContent = { Text(stringResource(R.string.language_setting)) },
+                    supportingContent = { Text(stringResource(R.string.language_setting_support)) },
+                    modifier = Modifier.clickable { dialogState = DialogState.LANGUAGE }
+                )
+            }
+
             // RATE THIS APP
             if (BuildConfig.STORE_LINK.isNotEmpty()) {
                 item {
@@ -257,6 +275,7 @@ internal fun SettingsScreen(
                 dismissAction = { resetDialog() }
             )
         }
+
         DialogState.UNIT_LIST_SORTING -> {
             AlertDialogWithList(
                 title = stringResource(R.string.units_sorting),
@@ -271,6 +290,29 @@ internal fun SettingsScreen(
                 dismissAction = { resetDialog() }
             )
         }
+
+        DialogState.LANGUAGE -> {
+            AlertDialogWithList(
+                title = stringResource(R.string.language_setting),
+                listItems = mapOf(
+                    "" to R.string.auto_label,
+                    "en" to R.string.locale_en,
+                    "de" to R.string.locale_de,
+                    "en_rGB" to R.string.locale_en_rGB,
+                    "fr" to R.string.locale_fr,
+                    "it" to R.string.locale_it,
+                    "ru" to R.string.locale_ru,
+                ),
+                selectedItemIndex = AppCompatDelegate.getApplicationLocales().toLanguageTags(),
+                selectAction = {
+                    val selectedLocale = if (it == "") LocaleListCompat.getEmptyLocaleList()
+                        else LocaleListCompat.forLanguageTags(it)
+
+                    AppCompatDelegate.setApplicationLocales(selectedLocale)
+                },
+                dismissAction = { resetDialog() }
+            )
+        }
         // Dismissing alert dialog
         else -> {}
     }
@@ -280,5 +322,5 @@ internal fun SettingsScreen(
  * All possible states for alert dialog that opens when user clicks on settings.
  */
 private enum class DialogState {
-    NONE, START_SCREEN, UNIT_LIST_SORTING
+    NONE, START_SCREEN, UNIT_LIST_SORTING, LANGUAGE
 }

gradle/libs.versions.toml

@@ -12,6 +12,7 @@ androidxComposeMaterial3 = "1.2.0-alpha04"
 androidxNavigation = "2.6.0"
 androidxLifecycleRuntimeCompose = "2.6.1"
 androidxHilt = "1.0.0"
+androidxAppCompat = "1.6.1"
 comGoogleDagger = "2.47"
 androidxComposeMaterialIconsExtended = "1.6.0-alpha02"
 androidxDatastore = "1.0.0"
@@ -61,6 +62,7 @@ com-squareup-retrofit2 = { group = "com.squareup.retrofit2", name = "converter-m
 com-github-sadellie-themmo = { group = "com.github.sadellie", name = "themmo", version.ref = "comGithubSadellieThemmo" }
 org-burnoutcrew-composereorderable = { group = "org.burnoutcrew.composereorderable", name = "reorderable", version.ref = "orgBurnoutcrewComposereorderable" }
 android-desugarJdkLibs = { group = "com.android.tools", name = "desugar_jdk_libs", version.ref = "androidDesugarJdkLibs" }
+androidx-appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "androidxAppCompat" }
 
 # classpath
 android-gradlePlugin = { group = "com.android.tools.build", name = "gradle", version.ref = "androidGradlePlugin" }