UI: finally support theme modes; remove hardcoded color schemes, default to dynamic color scheme implementation

examples/llama.android/app/src/main/java/com/example/llama/revamp/MainActivity.kt

@@ -50,7 +50,7 @@ import com.example.llama.revamp.viewmodel.MainViewModel
 import com.example.llama.revamp.viewmodel.ModelLoadingViewModel
 import com.example.llama.revamp.viewmodel.ModelSelectionViewModel
 import com.example.llama.revamp.viewmodel.ModelsManagementViewModel
-import com.example.llama.revamp.viewmodel.PerformanceViewModel
+import com.example.llama.revamp.viewmodel.SettingsViewModel
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.launch
 
@@ -58,13 +58,17 @@ import kotlinx.coroutines.launch
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+
         setContent {
-            LlamaTheme {
+            val settingsViewModel: SettingsViewModel = hiltViewModel()
+            val themeMode by settingsViewModel.themeMode.collectAsState()
+
+            LlamaTheme(themeMode) {
                 Surface(
                     modifier = Modifier.fillMaxSize(),
                     color = MaterialTheme.colorScheme.background
                 ) {
-                    AppContent()
+                    AppContent(settingsViewModel)
                 }
             }
         }
@@ -73,8 +77,8 @@ class MainActivity : ComponentActivity() {
 
 @Composable
 fun AppContent(
+    settingsViewModel: SettingsViewModel,
     mainViewModel: MainViewModel = hiltViewModel(),
-    performanceViewModel: PerformanceViewModel = hiltViewModel(),
     modelSelectionViewModel: ModelSelectionViewModel = hiltViewModel(),
     modelLoadingViewModel: ModelLoadingViewModel = hiltViewModel(),
     benchmarkViewModel: BenchmarkViewModel = hiltViewModel(),
@@ -88,10 +92,10 @@ fun AppContent(
     val engineState by mainViewModel.engineState.collectAsState()
 
     // Metric states for scaffolds
-    val memoryUsage by performanceViewModel.memoryUsage.collectAsState()
+    val memoryUsage by settingsViewModel.memoryUsage.collectAsState()
-    val temperatureInfo by performanceViewModel.temperatureMetrics.collectAsState()
+    val temperatureInfo by settingsViewModel.temperatureMetrics.collectAsState()
-    val useFahrenheit by performanceViewModel.useFahrenheitUnit.collectAsState()
+    val useFahrenheit by settingsViewModel.useFahrenheitUnit.collectAsState()
-    val storageMetrics by performanceViewModel.storageMetrics.collectAsState()
+    val storageMetrics by settingsViewModel.storageMetrics.collectAsState()
 
     // Navigation
     val navController = rememberNavController()
@@ -293,9 +297,6 @@ fun AppContent(
                 // Model Selection Screen
                 composable(AppDestinations.MODEL_SELECTION_ROUTE) {
                     ModelSelectionScreen(
-                        onNavigateBack = {
-                            navigationActions.navigateUp()
-                        },
                         onModelConfirmed = { modelInfo ->
                             navigationActions.navigateToModelLoading()
                         },
@@ -371,7 +372,9 @@ fun AppContent(
 
                 // Settings General Screen
                 composable(AppDestinations.SETTINGS_GENERAL_ROUTE) {
-                    SettingsGeneralScreen()
+                    SettingsGeneralScreen(
+                        viewModel = settingsViewModel
+                    )
                 }
 
                 // Models Management Screen

examples/llama.android/app/src/main/java/com/example/llama/revamp/data/preferences/UserPreferences.kt

@@ -5,6 +5,7 @@ import androidx.datastore.core.DataStore
 import androidx.datastore.preferences.core.Preferences
 import androidx.datastore.preferences.core.booleanPreferencesKey
 import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.intPreferencesKey
 import androidx.datastore.preferences.core.longPreferencesKey
 import androidx.datastore.preferences.preferencesDataStore
 import dagger.hilt.android.qualifiers.ApplicationContext
@@ -28,9 +29,15 @@ class UserPreferences @Inject constructor (
         val PERFORMANCE_MONITORING_ENABLED = booleanPreferencesKey("performance_monitoring_enabled")
         val USE_FAHRENHEIT_TEMPERATURE = booleanPreferencesKey("use_fahrenheit_temperature")
         val MONITORING_INTERVAL_MS = longPreferencesKey("monitoring_interval_ms")
+        val THEME_MODE = intPreferencesKey("theme_mode")
 
         // Default values
         const val DEFAULT_MONITORING_INTERVAL_MS = 5000L
+
+        // Theme mode values
+        const val THEME_MODE_AUTO = 0
+        const val THEME_MODE_LIGHT = 1
+        const val THEME_MODE_DARK = 2
     }
 
     /**
@@ -38,7 +45,7 @@ class UserPreferences @Inject constructor (
      */
     fun isPerformanceMonitoringEnabled(): Flow<Boolean> {
         return context.dataStore.data.map { preferences ->
-            preferences[PERFORMANCE_MONITORING_ENABLED] ?: true
+            preferences[PERFORMANCE_MONITORING_ENABLED] != false
         }
     }
 
@@ -56,7 +63,7 @@ class UserPreferences @Inject constructor (
      */
     fun usesFahrenheitTemperature(): Flow<Boolean> {
         return context.dataStore.data.map { preferences ->
-            preferences[USE_FAHRENHEIT_TEMPERATURE] ?: false
+            preferences[USE_FAHRENHEIT_TEMPERATURE] == true
         }
     }
 
@@ -88,4 +95,22 @@ class UserPreferences @Inject constructor (
             preferences[MONITORING_INTERVAL_MS] = intervalMs
         }
     }
+
+    /**
+     * Gets the current theme mode.
+     */
+    fun getThemeMode(): Flow<Int> {
+        return context.dataStore.data.map { preferences ->
+            preferences[THEME_MODE] ?: THEME_MODE_AUTO
+        }
+    }
+
+    /**
+     * Sets the theme mode.
+     */
+    suspend fun setThemeMode(mode: Int) {
+        context.dataStore.edit { preferences ->
+            preferences[THEME_MODE] = mode
+        }
+    }
 }

examples/llama.android/app/src/main/java/com/example/llama/revamp/ui/screens/SettingsGeneralScreen.kt

@@ -12,6 +12,9 @@ import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Card
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SegmentedButton
+import androidx.compose.material3.SegmentedButtonDefaults
+import androidx.compose.material3.SingleChoiceSegmentedButtonRow
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -20,20 +23,21 @@ import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
-import androidx.hilt.navigation.compose.hiltViewModel
 import com.example.llama.revamp.APP_NAME
-import com.example.llama.revamp.viewmodel.PerformanceViewModel
+import com.example.llama.revamp.data.preferences.UserPreferences
+import com.example.llama.revamp.viewmodel.SettingsViewModel
 
 /**
  * Screen for general app settings
  */
 @Composable
 fun SettingsGeneralScreen(
-    performanceViewModel: PerformanceViewModel = hiltViewModel(),
+    viewModel: SettingsViewModel,
 ) {
     // Collect state from ViewModel
-    val isMonitoringEnabled by performanceViewModel.isMonitoringEnabled.collectAsState()
+    val isMonitoringEnabled by viewModel.isMonitoringEnabled.collectAsState()
-    val useFahrenheit by performanceViewModel.useFahrenheitUnit.collectAsState()
+    val useFahrenheit by viewModel.useFahrenheitUnit.collectAsState()
+    val themeMode by viewModel.themeMode.collectAsState()
 
     Column(
         modifier = Modifier
@@ -44,28 +48,66 @@ fun SettingsGeneralScreen(
         SettingsCategory(title = "Performance Monitoring") {
             SettingsSwitch(
                 title = "Enable Monitoring",
-                description = "Display memory, battery and temperature information",
+                description = "Display memory, battery and temperature info",
                 checked = isMonitoringEnabled,
-                onCheckedChange = { performanceViewModel.setMonitoringEnabled(it) }
+                onCheckedChange = { viewModel.setMonitoringEnabled(it) }
             )
 
             SettingsSwitch(
                 title = "Use Fahrenheit",
                 description = "Display temperature in Fahrenheit instead of Celsius",
                 checked = useFahrenheit,
-                onCheckedChange = { performanceViewModel.setUseFahrenheitUnit(it) }
+                onCheckedChange = { viewModel.setUseFahrenheitUnit(it) }
             )
         }
 
         SettingsCategory(title = "Theme") {
-            SettingsSwitch(
+            Column(
-                title = "Dark Theme",
+                modifier = Modifier
-                description = "Use dark theme throughout the app",
+                    .fillMaxWidth()
-                checked = true, // This would be connected to theme state in a real app
+                    .padding(16.dp)
-                onCheckedChange = {
+            ) {
-                    /* TODO-hyin: Implement theme switching between Auto, Light and Dark */
+                Text(
-                }
+                    text = "Theme Mode",
+                    style = MaterialTheme.typography.titleMedium
                 )
+
+                Text(
+                    text = "Follow system setting or override with your choice",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                )
+
+                Spacer(modifier = Modifier.height(16.dp))
+
+                SingleChoiceSegmentedButtonRow(
+                    modifier = Modifier.fillMaxWidth()
+                ) {
+                    SegmentedButton(
+                        selected = themeMode == UserPreferences.THEME_MODE_AUTO,
+                        onClick = { viewModel.setThemeMode(UserPreferences.THEME_MODE_AUTO) },
+                        shape = SegmentedButtonDefaults.itemShape(index = 0, count = 3)
+                    ) {
+                        Text("Auto")
+                    }
+
+                    SegmentedButton(
+                        selected = themeMode == UserPreferences.THEME_MODE_LIGHT,
+                        onClick = { viewModel.setThemeMode(UserPreferences.THEME_MODE_LIGHT) },
+                        shape = SegmentedButtonDefaults.itemShape(index = 1, count = 3)
+                    ) {
+                        Text("Light")
+                    }
+
+                    SegmentedButton(
+                        selected = themeMode == UserPreferences.THEME_MODE_DARK,
+                        onClick = { viewModel.setThemeMode(UserPreferences.THEME_MODE_DARK) },
+                        shape = SegmentedButtonDefaults.itemShape(index = 2, count = 3)
+                    ) {
+                        Text("Dark")
+                    }
+                }
+            }
         }
 
         SettingsCategory(title = "About") {

examples/llama.android/app/src/main/java/com/example/llama/revamp/ui/theme/Color.kt

@@ -64,8 +64,3 @@ val md_theme_dark_inversePrimary = Color(0xFF6750A4)
 val md_theme_dark_surfaceTint = Color(0xFFCFBCFF)
 val md_theme_dark_outlineVariant = Color(0xFF49454E)
 val md_theme_dark_scrim = Color(0xFF000000)
-
-// Additional app-specific colors
-val CriticalColor = Color(0xFFFF0000)
-val WarningColor = Color(0xFFFFA000)
-val SuccessColor = Color(0xFF388E3C)

examples/llama.android/app/src/main/java/com/example/llama/revamp/ui/theme/Theme.kt

@@ -1,8 +1,6 @@
 package com.example.llama.revamp.ui.theme
 
-
 import android.app.Activity
-import android.os.Build
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.darkColorScheme
@@ -15,8 +13,10 @@ import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalView
 import androidx.core.view.WindowCompat
+import com.example.llama.revamp.data.preferences.UserPreferences
 import com.google.accompanist.systemuicontroller.rememberSystemUiController
 
+// TODO-han.yin: support more / custom color palettes?
 private val LightColorScheme = lightColorScheme(
     primary = md_theme_light_primary,
     onPrimary = md_theme_light_onPrimary,
@@ -83,19 +83,18 @@ private val DarkColorScheme = darkColorScheme(
 
 @Composable
 fun LlamaTheme(
-    darkTheme: Boolean = isSystemInDarkTheme(),
+    themeMode: Int = UserPreferences.THEME_MODE_AUTO,
-    // Dynamic color is available on Android 12+
-    dynamicColor: Boolean = false,
     content: @Composable () -> Unit
 ) {
-    val colorScheme = when {
+    val darkTheme = when (themeMode) {
-        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
+        UserPreferences.THEME_MODE_LIGHT -> false
+        UserPreferences.THEME_MODE_DARK -> true
+        else -> isSystemInDarkTheme()
+    }
+
     val context = LocalContext.current
+    val colorScheme =
         if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
-        }
-        darkTheme -> DarkColorScheme
-        else -> LightColorScheme
-    }
 
     val view = LocalView.current
     if (!view.isInEditMode) {

examples/llama.android/app/src/main/java/com/example/llama/revamp/viewmodel/SettingsViewModel.kt

@@ -22,7 +22,7 @@ import javax.inject.Inject
  * ViewModel that manages performance monitoring for the app.
  */
 @HiltViewModel
-class PerformanceViewModel @Inject constructor(
+class SettingsViewModel @Inject constructor(
     private val userPreferences: UserPreferences,
     private val performanceMonitor: PerformanceMonitor,
     private val modelRepository: ModelRepository,
@@ -54,17 +54,27 @@ class PerformanceViewModel @Inject constructor(
     private val _monitoringInterval = MutableStateFlow(5000L)
     val monitoringInterval: StateFlow<Long> = _monitoringInterval.asStateFlow()
 
+    private val _themeMode = MutableStateFlow(UserPreferences.THEME_MODE_AUTO)
+    val themeMode: StateFlow<Int> = _themeMode.asStateFlow()
+
     init {
         viewModelScope.launch {
             // Load user preferences
             _isMonitoringEnabled.value = userPreferences.isPerformanceMonitoringEnabled().first()
             _useFahrenheitUnit.value = userPreferences.usesFahrenheitTemperature().first()
             _monitoringInterval.value = userPreferences.getMonitoringInterval().first()
+            _themeMode.value = userPreferences.getThemeMode().first()
 
             // Start monitoring if enabled
             if (_isMonitoringEnabled.value) {
                 startMonitoring()
             }
+
+            viewModelScope.launch {
+                userPreferences.getThemeMode().collect { mode ->
+                    _themeMode.value = mode
+                }
+            }
         }
     }
 
@@ -144,4 +154,14 @@ class PerformanceViewModel @Inject constructor(
     private fun isMonitoringActive(): Boolean {
         return _isMonitoringEnabled.value
     }
+
+    /**
+     * Sets the theme mode.
+     */
+    fun setThemeMode(mode: Int) {
+        viewModelScope.launch {
+            userPreferences.setThemeMode(mode)
+            _themeMode.value = mode
+        }
+    }
 }