Add manual dark theme preference support

app/src/main/AndroidManifest.xml

@@ -18,7 +18,11 @@
             android:launchMode="singleTop"
             android:taskAffinity="moe.apex.breadboard.MainActivity"
             android:exported="true"
-            android:theme="@style/Theme.Breadboard">
+            android:theme="@style/Theme.Breadboard"
+            android:configChanges="uiMode"> <!-- Add "uiMode" to "configChanges" to prevent the
+                                                 activity from recreating itself during night mode
+                                                 change, avoiding unnecessary state resets wherever
+                                                 possible. -->
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
@@ -29,7 +33,8 @@
             android:taskAffinity="moe.apex.breadboard.DeepLinkActivity"
             android:launchMode="singleTop"
             android:exported="true"
-            android:theme="@style/Theme.Breadboard">
+            android:theme="@style/Theme.Breadboard"
+            android:configChanges="uiMode">
 
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />

app/src/main/java/moe/apex/breadboard/MainActivity.kt

@@ -1,5 +1,6 @@
 package moe.apex.breadboard
 
+import android.app.UiModeManager
 import android.content.Context
 import android.content.Intent
 import android.os.Build
@@ -35,6 +36,7 @@ import moe.apex.breadboard.navigation.Home
 import moe.apex.breadboard.navigation.Navigation
 import moe.apex.breadboard.navigation.Results
 import moe.apex.breadboard.navigation.Search
+import moe.apex.breadboard.preferences.DarkTheme
 import moe.apex.breadboard.preferences.ImageSource
 import moe.apex.breadboard.preferences.LocalPreferences
 import moe.apex.breadboard.preferences.StartDestination
@@ -123,6 +125,25 @@ class MainActivity : SingletonImageLoader.Factory, ComponentActivity(), VolumeBu
             val viewModel = getGlobalViewModel()
             val recommendationsProvider by viewModel.recommendationsProvider.collectAsState()
 
+            /* Sync the UiModeManager's app night mode preference with the selected app dark theme
+               preference. This ensures that the splash screen colour scheme matches the selected app
+               dark theme preference.
+
+               UiModeManager#setApplicationNightMode() is only supported on Android 12+. */
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+                val uiModeManager = getSystemService(UI_MODE_SERVICE) as UiModeManager
+
+                SideEffect(prefs.darkTheme) {
+                    uiModeManager.setApplicationNightMode(
+                        when (prefs.darkTheme) {
+                            DarkTheme.ON -> UiModeManager.MODE_NIGHT_YES
+                            DarkTheme.OFF -> UiModeManager.MODE_NIGHT_NO
+                            DarkTheme.AUTO -> UiModeManager.MODE_NIGHT_AUTO
+                        }
+                    )
+                }
+            }
+
             SideEffect(prefs.imageSource, prefs.filterRatingsLocally) {
                 if (
                     recommendationsProvider?.imageSource != prefs.imageSource ||

app/src/main/java/moe/apex/breadboard/home/FollowedArtistsScreen.kt

@@ -1,7 +1,6 @@
 package moe.apex.breadboard.home
 
 import androidx.compose.foundation.background
-import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -42,6 +41,7 @@ import moe.apex.breadboard.preferences.ImageSource
 import moe.apex.breadboard.preferences.LocalPreferences
 import moe.apex.breadboard.preferences.PreferenceKeys
 import moe.apex.breadboard.prefs
+import moe.apex.breadboard.ui.theme.shouldUseDarkTheme
 import moe.apex.breadboard.util.DISABLED_OPACITY
 import moe.apex.breadboard.util.ExpressiveTagEntryContainer
 import moe.apex.breadboard.util.LargeTitleBar
@@ -65,7 +65,7 @@ fun FollowedArtistsScreen(navController: NavHostController) {
     val userPreferencesRepository = LocalContext.current.prefs
     val prefs = LocalPreferences.current
     val followedTags = prefs.followedTags.toList().sorted()
-    val darkTheme = isSystemInDarkTheme()
+    val darkTheme = shouldUseDarkTheme()
 
     MainScreenScaffold(
         topAppBar = {

app/src/main/java/moe/apex/breadboard/preferences/LayoutSettingsScreen.kt

@@ -16,6 +16,7 @@ import androidx.compose.ui.unit.dp
 import androidx.navigation.NavHostController
 import kotlinx.coroutines.launch
 import moe.apex.breadboard.prefs
+import moe.apex.breadboard.ui.theme.doesSystemSupportDarkTheme
 import moe.apex.breadboard.util.LargeTitleBar
 import moe.apex.breadboard.util.LazyExpressiveGroup
 import moe.apex.breadboard.util.MainScreenScaffold
@@ -119,7 +120,26 @@ fun LayoutSettingsScreen(navController: NavHostController) {
                 }
             }
 
-            LazyExpressiveGroup("Layout") {
+            LazyExpressiveGroup("Appearance and Layout") {
+                item {
+                    EnumPref(
+                        title = "Dark theme",
+                        summary = currentSettings.darkTheme.label,
+                        enumItems = DarkTheme.entries.filter { entry ->
+                            // Hide the auto option if system dark theme is not supported
+                            !(entry == DarkTheme.AUTO && !doesSystemSupportDarkTheme())
+                        },
+                        selectedItem = currentSettings.darkTheme,
+                        onSelection = {
+                            scope.launch {
+                                preferencesRepository.updatePref(
+                                    PreferenceKeys.DARK_THEME,
+                                    it
+                                )
+                            }
+                        }
+                    )
+                }
                 item {
                     ReorderablePref(
                         title = "Reorder image actions",

app/src/main/java/moe/apex/breadboard/preferences/Pref.kt

@@ -45,6 +45,7 @@ import moe.apex.breadboard.image.Safebooru
 import moe.apex.breadboard.image.Yandere
 import moe.apex.breadboard.image.AI_TAG_NAMES
 import moe.apex.breadboard.tag.TagCategory
+import moe.apex.breadboard.ui.theme.doesSystemSupportDarkTheme
 import moe.apex.breadboard.util.AgeVerification
 import moe.apex.breadboard.util.MigrationOnlyField
 import moe.apex.breadboard.util.PixivArtwork
@@ -98,6 +99,7 @@ data object PrefNames {
     const val INTERNAL_IGNORE_LIST = "internal_ignore_list"
     const val AUTOPLAY_VIDEOS = "autoplay_videos"
     const val UNIFIED_INFO_SHEET = "unified_info_sheet"
+    const val DARK_THEME = "dark_theme"
     const val FOLLOWED_TAGS = "followed_tags"
     const val DEFAULT_BROWSE_TAB = "default_browse_tab"
     const val PROFILES_FOR_ALL_TAGS = "profiles_for_all_tags"
@@ -136,6 +138,7 @@ object PreferenceKeys {
     val INTERNAL_IGNORE_LIST = stringSetPreferencesKey(PrefNames.INTERNAL_IGNORE_LIST)
     val AUTOPLAY_VIDEOS = stringPreferencesKey(PrefNames.AUTOPLAY_VIDEOS)
     val UNIFIED_INFO_SHEET = booleanPreferencesKey(PrefNames.UNIFIED_INFO_SHEET)
+    val DARK_THEME = stringPreferencesKey(PrefNames.DARK_THEME)
     val FOLLOWED_TAGS = stringSetPreferencesKey(PrefNames.FOLLOWED_TAGS)
     val DEFAULT_BROWSE_TAB = stringPreferencesKey(PrefNames.DEFAULT_BROWSE_TAB)
     val PROFILES_FOR_ALL_TAGS = booleanPreferencesKey(PrefNames.PROFILES_FOR_ALL_TAGS)
@@ -243,6 +246,7 @@ data class Prefs(
     val internalIgnoreList: Set<String>,
     val autoplayVideos: AutoplayVideosMode,
     val unifiedInfoSheet: Boolean,
+    val darkTheme: DarkTheme,
     val followedTags: Set<String>,
     val defaultBrowseTab: BrowseTab,
     val profilesForAllTags: Boolean,
@@ -280,6 +284,7 @@ data class Prefs(
             internalIgnoreList = emptySet(),
             autoplayVideos = AutoplayVideosMode.OFF,
             unifiedInfoSheet = false, // Unified is called 'Classic' in the UI
+            darkTheme = DarkTheme.AUTO,
             followedTags = emptySet(),
             defaultBrowseTab = BrowseTab.FOR_YOU,
             profilesForAllTags = false,
@@ -350,6 +355,7 @@ class UserPreferencesRepository(private val dataStore: DataStore<Preferences>) {
             PreferenceKeys.INTERNAL_IGNORE_LIST_TIMESTAMP to PrefMeta(PrefCategory.SETTING, exportable = false),
             PreferenceKeys.INTERNAL_IGNORE_LIST to PrefMeta(PrefCategory.SETTING, exportable = false),
             PreferenceKeys.UNIFIED_INFO_SHEET to PrefMeta(PrefCategory.SETTING),
+            PreferenceKeys.DARK_THEME to PrefMeta(PrefCategory.SETTING),
             PreferenceKeys.FOLLOWED_TAGS to PrefMeta(PrefCategory.SETTING, mergeable = true),
             PreferenceKeys.DEFAULT_BROWSE_TAB to PrefMeta(PrefCategory.SETTING),
             PreferenceKeys.PROFILES_FOR_ALL_TAGS to PrefMeta(PrefCategory.SETTING),
@@ -393,6 +399,18 @@ class UserPreferencesRepository(private val dataStore: DataStore<Preferences>) {
         val currentPreferences = dataStore.data.first()
         val lastUsedVersionCode = currentPreferences[PreferenceKeys.LAST_USED_VERSION_CODE] ?: 0
 
+        /* Version 3.3.2 introduces the manual dark theme preference. Android 9 had some partial
+           support for system dark theme, but older versions would have no support whatsoever.
+           Set the default dark theme preference to a manual OFF state on those versions. */
+        val darkTheme = currentPreferences[PreferenceKeys.DARK_THEME]
+
+        if (
+            !doesSystemSupportDarkTheme() &&
+            (darkTheme == null || darkTheme == DarkTheme.AUTO.name)
+        ) {
+            updatePref(PreferenceKeys.DARK_THEME, DarkTheme.OFF)
+        }
+
         /* lastUsedVersionCode can be 0 if the user had it installed already but cleared the data.
            In such a case, we can't reliably determine what their previous version was. Just load
            the default settings. */
@@ -858,6 +876,7 @@ class UserPreferencesRepository(private val dataStore: DataStore<Preferences>) {
         val internalIgnoreList = preferences[PreferenceKeys.INTERNAL_IGNORE_LIST] ?: Prefs.DEFAULT.internalIgnoreList
         val autoplayVideos = preferences[PreferenceKeys.AUTOPLAY_VIDEOS]?.let { AutoplayVideosMode.valueOf(it) } ?: Prefs.DEFAULT.autoplayVideos
         val unifiedInfoSheet = preferences[PreferenceKeys.UNIFIED_INFO_SHEET] ?: Prefs.DEFAULT.unifiedInfoSheet
+        val darkTheme = preferences[PreferenceKeys.DARK_THEME]?.let { DarkTheme.valueOf(it) } ?: Prefs.DEFAULT.darkTheme
         val followedTags = preferences[PreferenceKeys.FOLLOWED_TAGS] ?: Prefs.DEFAULT.followedTags
         val defaultBrowseTab = preferences[PreferenceKeys.DEFAULT_BROWSE_TAB]?.let { BrowseTab.valueOf(it) } ?: Prefs.DEFAULT.defaultBrowseTab
         val profilesForAllTags = preferences[PreferenceKeys.PROFILES_FOR_ALL_TAGS] ?: Prefs.DEFAULT.profilesForAllTags
@@ -894,6 +913,7 @@ class UserPreferencesRepository(private val dataStore: DataStore<Preferences>) {
             internalIgnoreList,
             autoplayVideos,
             unifiedInfoSheet,
+            darkTheme,
             followedTags,
             defaultBrowseTab,
             profilesForAllTags,
@@ -913,3 +933,10 @@ enum class ImageSource(override val label: String, val imageBoard: ImageBoard) :
     YANDERE("Yande.re", Yandere),
     R34("Rule34", Rule34)
 }
+
+
+enum class DarkTheme(override val label: String) : PrefEnum<DarkTheme> {
+    ON("Always"),
+    OFF("Never"),
+    AUTO("Follow system")
+}

app/src/main/java/moe/apex/breadboard/preferences/Preferences.kt

@@ -1,7 +1,6 @@
 package moe.apex.breadboard.preferences
 
 import androidx.compose.foundation.background
-import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.fillMaxSize
@@ -47,6 +46,7 @@ import moe.apex.breadboard.navigation.DataSettings
 import moe.apex.breadboard.navigation.ExperimentalSettings
 import moe.apex.breadboard.navigation.GeneralSettings
 import moe.apex.breadboard.navigation.LayoutSettings
+import moe.apex.breadboard.ui.theme.shouldUseDarkTheme
 import moe.apex.breadboard.util.ChevronRight
 import moe.apex.breadboard.util.LazyExpressiveGroup
 import moe.apex.breadboard.util.MainScreenScaffold
@@ -194,7 +194,7 @@ private fun ContainedIcon(
     label: String,
     imageVector: ImageVector
 ) {
-    val darkTheme = isSystemInDarkTheme()
+    val darkTheme = shouldUseDarkTheme()
     val colourPair = remember(label) {
         generateColours(darkTheme, label)
     }

app/src/main/java/moe/apex/breadboard/ui/theme/Theme.kt

@@ -1,6 +1,10 @@
 package moe.apex.breadboard.ui.theme
 
 import android.os.Build
+import androidx.activity.ComponentActivity
+import androidx.activity.SystemBarStyle
+import androidx.activity.compose.LocalActivity
+import androidx.activity.enableEdgeToEdge
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
 import androidx.compose.material3.MaterialExpressiveTheme
@@ -11,9 +15,12 @@ import androidx.compose.material3.lightColorScheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.staticCompositionLocalOf
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.LocalContext
+import moe.apex.breadboard.preferences.DarkTheme
+import moe.apex.breadboard.preferences.LocalPreferences
 
 
 private val DarkColorScheme = darkColorScheme(
@@ -54,14 +61,58 @@ val LocalBreadboardColors = staticCompositionLocalOf {
 }
 
 
+@Composable
+fun shouldUseDarkTheme(): Boolean {
+    val preferences = LocalPreferences.current
+
+    return when (preferences.darkTheme) {
+        DarkTheme.ON -> true
+        DarkTheme.OFF -> false
+        DarkTheme.AUTO -> isSystemInDarkTheme()
+    }
+}
+
+
+fun doesSystemSupportDarkTheme(): Boolean {
+    /* Android 9 had some partial support for system dark theme,
+       but older versions would have no support whatsoever. */
+    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.P
+}
+
+
 @OptIn(ExperimentalMaterial3ExpressiveApi::class)
 @Composable
 fun BreadboardTheme(
-        darkTheme: Boolean = isSystemInDarkTheme(),
+        darkTheme: Boolean = shouldUseDarkTheme(),
         // Dynamic color is available on Android 12+
         dynamicColor: Boolean = true,
         content: @Composable () -> Unit
 ) {
+    /* Ensure that the status bar and navigation bar colour scheme match the current app dark theme
+       preference. This is necessary on Android 11 and lower if the app dark theme preference
+       is the opposite of the system dark theme preference.
+
+       This is not necessary for Android 12+ since we already sync the UiModeManager's app night mode
+       preference to match the app dark theme preference, so the system changes the style accordingly. */
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S) {
+        val context = LocalActivity.current as ComponentActivity
+
+        SideEffect(darkTheme) {
+            val systemBarStyle = if (darkTheme) {
+                SystemBarStyle.dark(
+                    scrim = android.graphics.Color.TRANSPARENT
+                )
+            } else {
+                SystemBarStyle.light(
+                    scrim = android.graphics.Color.TRANSPARENT,
+                    darkScrim = android.graphics.Color.TRANSPARENT
+                )
+            }
+
+            context.enableEdgeToEdge(statusBarStyle = systemBarStyle, navigationBarStyle = systemBarStyle)
+        }
+    }
+
     var colorScheme = when {
         dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
             val context = LocalContext.current