feat(settings): move language to its own section with scalable dropdown picker (#906)

- New Language row in the main Settings list with current-language summary
- New SettingsLanguage drill-down page with an OutlinedButton + DropdownMenu
  picker (scales to any number of languages; same pattern as theme presets)
- Shared supportedLanguages()/languageLabel() helpers — adding a language
  is now one entry in one place
- Removed the 4-option segmented pill row from the Appearance page
- Added settings_sec_language string (en + zh)

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/Navigation.kt

@@ -56,6 +56,7 @@ import com.m57.hermescontrol.ui.settings.SettingsAppearancePage
 import com.m57.hermescontrol.ui.settings.SettingsBehaviorPage
 import com.m57.hermescontrol.ui.settings.SettingsChatPage
 import com.m57.hermescontrol.ui.settings.SettingsConnectionPage
+import com.m57.hermescontrol.ui.settings.SettingsLanguagePage
 import com.m57.hermescontrol.ui.settings.SettingsViewModel
 import com.m57.hermescontrol.ui.toolsets.ToolsetDetailScreen
 import kotlinx.coroutines.launch
@@ -113,6 +114,12 @@ private fun appEntryProvider(
             viewModel = viewModel { SettingsViewModel() },
         )
     }
+    entry<SettingsLanguage> {
+        SettingsLanguagePage(
+            onBack = { NavigationController.goBack() },
+            viewModel = viewModel { SettingsViewModel() },
+        )
+    }
     entry<SettingsChat> {
         SettingsChatPage(
             onBack = { NavigationController.goBack() },

app/src/main/java/com/m57/hermescontrol/NavigationKeys.kt

@@ -75,6 +75,8 @@ import kotlinx.serialization.Serializable
 
 @Serializable data object SettingsAppearance : NavKey
 
+@Serializable data object SettingsLanguage : NavKey
+
 @Serializable data object SettingsChat : NavKey
 
 @Serializable data object SettingsBehavior : NavKey

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsScreen.kt

@@ -12,6 +12,7 @@ import androidx.compose.material.icons.automirrored.filled.ArrowForward
 import androidx.compose.material.icons.automirrored.filled.ListAlt
 import androidx.compose.material.icons.filled.ChatBubbleOutline
 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.Tune
 import androidx.compose.material3.Card
@@ -39,9 +40,11 @@ import com.m57.hermescontrol.SettingsAppearance
 import com.m57.hermescontrol.SettingsBehavior
 import com.m57.hermescontrol.SettingsChat
 import com.m57.hermescontrol.SettingsConnection
+import com.m57.hermescontrol.SettingsLanguage
 import com.m57.hermescontrol.theme.ThemePreference
 import com.m57.hermescontrol.ui.common.HermesScaffold
 import com.m57.hermescontrol.ui.common.NavIcon
+import com.m57.hermescontrol.ui.settings.components.languageLabel
 
 @Composable
 fun SettingsScreen(
@@ -87,6 +90,12 @@ fun SettingsScreen(
                             summary = appearanceSummary(state),
                             onClick = { NavigationController.navigateTo(SettingsAppearance) },
                         ),
+                        SettingsRow(
+                            icon = Icons.Filled.Language,
+                            label = stringResource(R.string.settings_sec_language),
+                            summary = languageLabel(state.appLanguage),
+                            onClick = { NavigationController.navigateTo(SettingsLanguage) },
+                        ),
                         SettingsRow(
                             icon = Icons.Filled.ChatBubbleOutline,
                             label = stringResource(R.string.settings_sec_chat),
@@ -121,22 +130,12 @@ fun SettingsScreen(
 }
 
 @Composable
-private fun appearanceSummary(state: SettingsUiState): String {
-    val theme =
-        when (state.themePreference) {
-            ThemePreference.SYSTEM -> stringResource(R.string.settings_summary_theme_system)
-            ThemePreference.LIGHT -> stringResource(R.string.settings_summary_theme_light)
-            ThemePreference.DARK -> stringResource(R.string.settings_summary_theme_dark)
-        }
-    val lang =
-        when (state.appLanguage) {
-            "system" -> stringResource(R.string.language_system)
-            "zh" -> stringResource(R.string.language_chinese)
-            "ko" -> stringResource(R.string.language_korean)
-            else -> stringResource(R.string.language_english)
-        }
-    return "$theme · $lang"
-}
+private fun appearanceSummary(state: SettingsUiState): String =
+    when (state.themePreference) {
+        ThemePreference.SYSTEM -> stringResource(R.string.settings_summary_theme_system)
+        ThemePreference.LIGHT -> stringResource(R.string.settings_summary_theme_light)
+        ThemePreference.DARK -> stringResource(R.string.settings_summary_theme_dark)
+    }
 
 private data class SettingsRow(
     val icon: ImageVector,

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsSubPages.kt

@@ -36,6 +36,7 @@ import com.m57.hermescontrol.ui.settings.components.AppearanceSection
 import com.m57.hermescontrol.ui.settings.components.BehaviorSection
 import com.m57.hermescontrol.ui.settings.components.ChatSection
 import com.m57.hermescontrol.ui.settings.components.ConnectionSection
+import com.m57.hermescontrol.ui.settings.components.LanguageSection
 import com.m57.hermescontrol.ui.settings.components.TestConnectionButton
 import com.m57.hermescontrol.ui.settings.components.TestResultCard
 
@@ -132,6 +133,32 @@ internal fun SettingsAppearancePage(
                 onUseDynamicColorsChange = viewModel::onUseDynamicColorsChange,
                 themePreset = state.themePreset,
                 onThemePresetChange = viewModel::onThemePresetChange,
+            )
+        }
+    }
+}
+
+@Composable
+internal fun SettingsLanguagePage(
+    onBack: () -> Unit,
+    viewModel: SettingsViewModel = viewModel { SettingsViewModel() },
+) {
+    val state by viewModel.uiState.collectAsStateWithLifecycle()
+
+    HermesScaffold(
+        title = { Text(stringResource(R.string.settings_sec_language)) },
+        navigationIcon = NavIcon.Back(onBack),
+        drawerGesturesEnabled = false,
+    ) {
+        Column(
+            modifier =
+                Modifier
+                    .fillMaxSize()
+                    .verticalScroll(rememberScrollState())
+                    .padding(horizontal = 16.dp, vertical = 8.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            LanguageSection(
                 appLanguage = state.appLanguage,
                 onAppLanguageChange = viewModel::onAppLanguageChange,
             )

app/src/main/java/com/m57/hermescontrol/ui/settings/components/AppearanceSection.kt

@@ -1,6 +1,5 @@
 package com.m57.hermescontrol.ui.settings.components
 
-import androidx.activity.compose.LocalActivity
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -35,7 +34,6 @@ import com.m57.hermescontrol.R
 import com.m57.hermescontrol.theme.ThemePreference
 import com.m57.hermescontrol.theme.ThemePreset
 import com.m57.hermescontrol.ui.settings.SectionCard
-import com.m57.hermescontrol.util.LocaleContextWrapper
 
 @Composable
 internal fun AppearanceSection(
@@ -45,8 +43,6 @@ internal fun AppearanceSection(
     onUseDynamicColorsChange: (Boolean) -> Unit,
     themePreset: ThemePreset,
     onThemePresetChange: (ThemePreset) -> Unit,
-    appLanguage: String,
-    onAppLanguageChange: (String) -> Unit,
 ) {
     SectionCard {
         Text(
@@ -189,43 +185,6 @@ internal fun AppearanceSection(
                 }
             }
         }
-
-        Spacer(modifier = Modifier.height(16.dp))
-
-        Text(
-            text = stringResource(R.string.settings_item_language),
-            style = MaterialTheme.typography.bodyLarge,
-        )
-        Spacer(modifier = Modifier.height(8.dp))
-        val languageOptions =
-            listOf(
-                LocaleContextWrapper.SYSTEM_LANGUAGE to stringResource(R.string.language_system),
-                "en" to stringResource(R.string.language_english),
-                "zh" to stringResource(R.string.language_chinese),
-                "ko" to stringResource(R.string.language_korean),
-            )
-        SingleChoiceSegmentedButtonRow(modifier = Modifier.fillMaxWidth()) {
-            val activity = LocalActivity.current
-            languageOptions.forEachIndexed { index, (code, label) ->
-                SegmentedButton(
-                    selected = appLanguage == code,
-                    onClick = {
-                        onAppLanguageChange(code)
-                        // MainActivity is a plain ComponentActivity (not
-                        // AppCompatActivity), so the locale only takes effect
-                        // after the activity is recreated.
-                        activity?.recreate()
-                    },
-                    shape =
-                        SegmentedButtonDefaults.itemShape(
-                            index = index,
-                            count = languageOptions.size,
-                        ),
-                ) {
-                    Text(label)
-                }
-            }
-        }
     }
 }
 

app/src/main/java/com/m57/hermescontrol/ui/settings/components/LanguageSection.kt

@@ -0,0 +1,90 @@
+package com.m57.hermescontrol.ui.settings.components
+
+import androidx.activity.compose.LocalActivity
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import com.m57.hermescontrol.R
+import com.m57.hermescontrol.ui.settings.SectionCard
+import com.m57.hermescontrol.util.LocaleContextWrapper
+
+/**
+ * Supported languages as (code, display label) pairs. Add a new language
+ * here (plus its label in strings.xml) and both the picker and the summary
+ * adapt automatically.
+ */
+@Composable
+internal fun supportedLanguages(): List<Pair<String, String>> =
+    listOf(
+        LocaleContextWrapper.SYSTEM_LANGUAGE to stringResource(R.string.language_system),
+        "en" to stringResource(R.string.language_english),
+        "zh" to stringResource(R.string.language_chinese),
+        "ko" to stringResource(R.string.language_korean),
+    )
+
+/** Display label for a language code, falling back to English for unknown codes. */
+@Composable
+internal fun languageLabel(code: String): String =
+    supportedLanguages().firstOrNull { it.first == code }?.second
+        ?: stringResource(R.string.language_english)
+
+@Composable
+internal fun LanguageSection(
+    appLanguage: String,
+    onAppLanguageChange: (String) -> Unit,
+) {
+    SectionCard {
+        Text(
+            text = stringResource(R.string.settings_item_language),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+        Spacer(modifier = Modifier.height(8.dp))
+
+        val languageOptions = supportedLanguages()
+        val activity = LocalActivity.current
+        var expanded by remember { mutableStateOf(false) }
+        Box(modifier = Modifier.fillMaxWidth()) {
+            OutlinedButton(
+                onClick = { expanded = true },
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Text(languageLabel(appLanguage))
+            }
+            DropdownMenu(
+                expanded = expanded,
+                onDismissRequest = { expanded = false },
+                modifier = Modifier.fillMaxWidth(0.85f),
+            ) {
+                languageOptions.forEach { (code, label) ->
+                    DropdownMenuItem(
+                        text = { Text(label) },
+                        onClick = {
+                            expanded = false
+                            if (code != appLanguage) {
+                                onAppLanguageChange(code)
+                                // MainActivity is a plain ComponentActivity
+                                // (not AppCompatActivity), so the locale only
+                                // takes effect after the activity is recreated.
+                                activity?.recreate()
+                            }
+                        },
+                    )
+                }
+            }
+        }
+    }
+}