android: 2.14.0 - minSdk 23 + adaptive navigation (Stage 3)

- minSdkVersion 21 -> 23 (device is Android 17, no other users); jni
  Application.mk: APP_PLATFORM android-23 + -DHAVE_SIGWAITINFO (the NDK
  sysroot declares sigwaitinfo since API 23, conflicting with strongSwan's
  fallback prototype; the system implementation is used now)
- replace the bottom NavigationBar with NavigationSuiteScaffold (bottom bar
  on phones, navigation rail in landscape/on tablets); item colors keep the
  brand palette via NavigationSuiteItemColors(bar/rail/drawer)
- HomeScreen applies statusBarsPadding itself (the adaptive scaffold no
  longer pads the content area)
- predictive back was already enabled (android:enableOnBackInvokedCallback)

src/frontends/android/app/build.gradle

@@ -34,11 +34,11 @@ android {
     defaultConfig {
         applicationId "one.shx.strongswan.ext"
         compileSdk = 36
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 36
 
-        versionCode 152
+        versionCode 153
-        versionName "2.13.15"
+        versionName "2.14.0"
 
         /* Base URL of the update storage, trailing slash included */
         buildConfigField "String", "UPDATE_BASE_URL", "\"${updateBaseUrl}\""
@@ -146,15 +146,15 @@ dependencies {
     implementation 'androidx.work:work-runtime-ktx:2.10.1'
     implementation 'com.google.android.material:material:1.13.0'
 
-    /* BOM 2025.12.01 (compose 1.10) требует minSdk 23 — приложение поддерживает API 21.
+    /* BOM 2025.12.01 (compose 1.10, Expressive-тема) — отдельная задача после
-       2025.09.01 = первый BOM с material3 1.4.0 (Expressive) на compose 1.9 (minSdk 21). */
+       стабилизации; 2025.09.01 = material3 1.4.0 на compose 1.9. */
     def composeBom = platform('androidx.compose:compose-bom:2025.09.01')
     implementation composeBom
     implementation 'androidx.compose.ui:ui'
     implementation 'androidx.compose.material3:material3'
     implementation 'androidx.compose.material3:material3-window-size-class'
-    /* adaptive-navigation-suite требует minSdk 23 (adaptive:1.2.0) — подключить на этапе 3
+    /* adaptive-navigation-suite (NavigationSuiteScaffold): BOM 1.4.0, требует minSdk 23 */
-       вместе с решением о minSdk; сейчас приложение поддерживает API 21 */
+    implementation 'androidx.compose.material3:material3-adaptive-navigation-suite'
     implementation 'androidx.compose.material:material-icons-extended'
     implementation 'androidx.activity:activity-compose:1.11.0'
     implementation 'androidx.navigation:navigation-compose:2.9.4'

src/frontends/android/app/src/main/java/org/strongswan/android/ui/compose/HomeScreen.kt

@@ -44,6 +44,7 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.itemsIndexed
@@ -191,7 +192,9 @@ fun HomeScreen(
 		StatusGlowBackground(color = statusColor, active = connected || connecting)
 		LazyColumn(
 			state = listState,
-			modifier = Modifier.fillMaxSize(),
+			/* the adaptive navigation scaffold no longer pads the content area,
+			 * so the status headline offsets itself below the status bar */
+			modifier = Modifier.fillMaxSize().statusBarsPadding(),
 			horizontalAlignment = Alignment.CenterHorizontally,
 		)
 		{

src/frontends/android/app/src/main/java/org/strongswan/android/ui/compose/ShxApp.kt

@@ -24,10 +24,8 @@ import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.consumeWindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material.icons.Icons
@@ -43,13 +41,15 @@ import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Checkbox
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.NavigationBar
-import androidx.compose.material3.NavigationBarItem
 import androidx.compose.material3.NavigationBarItemDefaults
-import androidx.compose.material3.Scaffold
+import androidx.compose.material3.NavigationDrawerItemDefaults
+import androidx.compose.material3.NavigationRailItemDefaults
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
+import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteItemColors
+import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteScope
+import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteScaffold
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -57,6 +57,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.compositeOver
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.platform.LocalContext
@@ -107,17 +108,18 @@ fun ShxApp(viewModel: HomeViewModel = viewModel())
 	/* the home list keeps its scroll state across tab switches */
 	val homeListState = rememberLazyListState()
 
-	Scaffold(
+	/* adaptive navigation: bottom bar on phones, navigation rail in landscape
-		bottomBar = {
+	 * and on tablets (Stage 3 of ui-ux-plan).  Item colors are built here in a
-			ShxBottomBar(selected = state.tab, onSelect = viewModel::setTab)
+	 * composable context - the items lambda itself does not compose. */
+	val navItemColors = shxNavigationItemColors()
+	NavigationSuiteScaffold(
+		navigationSuiteItems = {
+			ShxNavigationSuiteItems(selected = state.tab, onSelect = viewModel::setTab, colors = navItemColors)
 		},
 		containerColor = MaterialTheme.colorScheme.background,
-	) { padding ->
+	) {
 		Surface(
-			modifier = Modifier
+			modifier = Modifier.fillMaxSize(),
-				.fillMaxSize()
-				.padding(padding)
-				.consumeWindowInsets(padding),
 			color = MaterialTheme.colorScheme.background,
 		) {
 			AnimatedContent(
@@ -206,14 +208,51 @@ private fun ShareProfileDialog(profile: VpnProfile, onDismiss: () -> Unit, onCon
 	)
 }
 
+/** Item colors for the adaptive navigation suite, keeping the brand palette. */
 @Composable
-private fun ShxBottomBar(selected: ShxTab, onSelect: (ShxTab) -> Unit)
+private fun shxNavigationItemColors(): NavigationSuiteItemColors
 {
 	val bg = MaterialTheme.colorScheme.surfaceContainer
 	val indicator = MaterialTheme.colorScheme.primary.copy(alpha = 0.32f).compositeOver(bg)
-	NavigationBar(containerColor = bg, tonalElevation = 0.dp) {
+	return NavigationSuiteItemColors(
+		navigationBarItemColors = NavigationBarItemDefaults.colors(
+			selectedIconColor = MaterialTheme.colorScheme.primary,
+			unselectedIconColor = MaterialTheme.colorScheme.onSurfaceVariant,
+			selectedTextColor = MaterialTheme.colorScheme.primary,
+			unselectedTextColor = MaterialTheme.colorScheme.onSurfaceVariant,
+			indicatorColor = indicator,
+		),
+		navigationRailItemColors = NavigationRailItemDefaults.colors(
+			selectedIconColor = MaterialTheme.colorScheme.primary,
+			unselectedIconColor = MaterialTheme.colorScheme.onSurfaceVariant,
+			selectedTextColor = MaterialTheme.colorScheme.primary,
+			unselectedTextColor = MaterialTheme.colorScheme.onSurfaceVariant,
+			indicatorColor = indicator,
+		),
+		navigationDrawerItemColors = NavigationDrawerItemDefaults.colors(
+			selectedContainerColor = indicator,
+			unselectedContainerColor = Color.Transparent,
+			selectedIconColor = MaterialTheme.colorScheme.primary,
+			unselectedIconColor = MaterialTheme.colorScheme.onSurfaceVariant,
+			selectedTextColor = MaterialTheme.colorScheme.primary,
+			unselectedTextColor = MaterialTheme.colorScheme.onSurfaceVariant,
+		),
+	)
+}
+
+/**
+ * Registers the app tabs as navigation suite items.  The scope's item() is a
+ * plain registration function - only the icon/label lambdas compose - so
+ * colors are built outside (in a composable context) and passed in.
+ */
+private fun NavigationSuiteScope.ShxNavigationSuiteItems(
+	selected: ShxTab,
+	onSelect: (ShxTab) -> Unit,
+	colors: NavigationSuiteItemColors,
+)
+{
 	ShxTab.entries.forEach { tab ->
-			NavigationBarItem(
+		item(
 			selected = tab == selected,
 			onClick = { onSelect(tab) },
 			icon = {
@@ -223,17 +262,10 @@ private fun ShxBottomBar(selected: ShxTab, onSelect: (ShxTab) -> Unit)
 				)
 			},
 			label = { Text(stringResource(tab.label())) },
-				colors = NavigationBarItemDefaults.colors(
+			colors = colors,
-					selectedIconColor = MaterialTheme.colorScheme.primary,
-					unselectedIconColor = MaterialTheme.colorScheme.onSurfaceVariant,
-					selectedTextColor = MaterialTheme.colorScheme.primary,
-					unselectedTextColor = MaterialTheme.colorScheme.onSurfaceVariant,
-					indicatorColor = indicator,
-				),
 		)
 	}
 }
-}
 
 private fun ShxTab.icon(selected: Boolean): ImageVector = when (this)
 {

src/frontends/android/app/src/main/jni/Application.mk

@@ -1,3 +1,6 @@
-APP_PLATFORM := android-21
+APP_PLATFORM := android-23
 APP_SUPPORT_FLEXIBLE_PAGE_SIZES := true
 APP_ABI := armeabi-v7a arm64-v8a x86_64
+# minSdk 23: the NDK sysroot declares sigwaitinfo() (introduced in API 23),
+# so use the system implementation instead of strongSwan's fallback prototype
+APP_CFLAGS += -DHAVE_SIGWAITINFO