android: expressive motion - fade-through tabs, back to Connect, LoadingIndicator, wavy progress, snackbar messages

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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

@@ -7,6 +7,8 @@
  * option) any later version.
  */
 
+@file:OptIn(ExperimentalMaterial3ExpressiveApi::class)
+
 package org.strongswan.android.ui
 
 import android.Manifest
@@ -25,7 +27,8 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.Checkbox
-import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.LoadingIndicator
 import androidx.compose.material3.ListItem
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
@@ -162,7 +165,7 @@ private fun SelectedAppsScreen(
 			)
 			if (loading)
 			{
-				CircularProgressIndicator(Modifier.padding(24.dp).size(32.dp))
+				LoadingIndicator(Modifier.padding(24.dp).size(32.dp))
 			}
 			else
 			{

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

@@ -7,6 +7,8 @@
  * option) any later version.
  */
 
+@file:OptIn(ExperimentalMaterial3ExpressiveApi::class)
+
 package org.strongswan.android.ui.compose
 
 import androidx.compose.animation.AnimatedContent
@@ -72,7 +74,8 @@ import androidx.compose.material.icons.rounded.Wifi
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
-import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.LoadingIndicator
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.Icon
@@ -622,7 +625,7 @@ private fun ConnectionCard(
 					content = MaterialTheme.colorScheme.onErrorContainer,
 				) { Text(stringResource(R.string.disconnect), fontSize = 16.sp) }
 				State.CONNECTING, State.DISCONNECTING -> HeroButton(onClick = onCancel) {
-					CircularProgressIndicator(Modifier.size(18.dp), strokeWidth = 2.dp)
+					LoadingIndicator(Modifier.size(18.dp))
 					Spacer(Modifier.size(12.dp))
 					Text(stringResource(android.R.string.cancel), fontSize = 16.sp)
 				}
@@ -885,7 +888,7 @@ private fun AvailabilityCard(
 				)
 				if (probing)
 				{
-					CircularProgressIndicator(Modifier.size(14.dp), strokeWidth = 2.dp)
+					LoadingIndicator(Modifier.size(14.dp))
 					Spacer(Modifier.size(12.dp))
 				}
 				IconButton(onClick = onRefresh, enabled = !probing) {
@@ -906,7 +909,7 @@ private fun AvailabilityCard(
 					modifier = Modifier.padding(top = 4.dp),
 				)
 				{
-					CircularProgressIndicator(Modifier.size(14.dp), strokeWidth = 2.dp)
+					LoadingIndicator(Modifier.size(14.dp))
 					Text(
 						text = stringResource(R.string.availability_measuring),
 						style = MaterialTheme.typography.bodySmall,
@@ -1159,7 +1162,7 @@ private fun ProbeRow(result: ProbeResult, measuring: Boolean, history: List<Prob
 		Spacer(Modifier.size(8.dp))
 		if (result.ok && result.rttMs == null && measuring)
 		{
-			CircularProgressIndicator(Modifier.size(12.dp), strokeWidth = 1.5.dp)
+			LoadingIndicator(Modifier.size(12.dp))
 		}
 		else
 		{

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

@@ -37,7 +37,9 @@ import androidx.localbroadcastmanager.content.LocalBroadcastManager
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
@@ -125,6 +127,10 @@ data class HomeUiState(
 
 class HomeViewModel(app: Application) : AndroidViewModel(app), VpnStateService.VpnStateListener
 {
+	/* one-shot user messages (string resource ids), shown as snackbars by ShxApp */
+	private val _messages = MutableSharedFlow<Int>(extraBufferCapacity = 4)
+	val messages: SharedFlow<Int> = _messages
+
 	private val _ui = MutableStateFlow(HomeUiState())
 	val ui: StateFlow<HomeUiState> = _ui
 
@@ -379,7 +385,7 @@ class HomeViewModel(app: Application) : AndroidViewModel(app), VpnStateService.V
 			withContext(Dispatchers.Main) {
 				if (uri == null)
 				{
-					Toast.makeText(context, R.string.share_profile_failed, Toast.LENGTH_LONG).show()
+					_messages.tryEmit(R.string.share_profile_failed)
 					return@withContext
 				}
 				val intent = Intent(Intent.ACTION_SEND)
@@ -391,7 +397,7 @@ class HomeViewModel(app: Application) : AndroidViewModel(app), VpnStateService.V
 				}
 				catch (_: ActivityNotFoundException)
 				{
-					Toast.makeText(context, R.string.share_profile_failed, Toast.LENGTH_LONG).show()
+					_messages.tryEmit(R.string.share_profile_failed)
 				}
 			}
 		}

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

@@ -7,6 +7,8 @@
  * option) any later version.
  */
 
+@file:OptIn(ExperimentalMaterial3ExpressiveApi::class)
+
 package org.strongswan.android.ui.compose
 
 import androidx.activity.ComponentActivity
@@ -29,7 +31,8 @@ import androidx.compose.material.icons.rounded.Dns
 import androidx.compose.material.icons.rounded.FileDownload
 import androidx.compose.material.icons.rounded.Language
 import androidx.compose.material.icons.rounded.VpnKey
-import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.LoadingIndicator
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -138,7 +141,7 @@ fun ImportScreen(
 				modifier = Modifier.fillMaxSize(),
 				contentAlignment = Alignment.Center,
 			) {
-				CircularProgressIndicator()
+				LoadingIndicator()
 			}
 			return
 		}
@@ -240,7 +243,7 @@ fun ImportScreen(
 							}
 							if (model.userCertLoading)
 							{
-								CircularProgressIndicator(Modifier.size(18.dp), strokeWidth = 2.dp)
+								LoadingIndicator(Modifier.size(18.dp))
 							}
 						}
 						if (model.showImportUserCert)

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

@@ -7,6 +7,8 @@
  * option) any later version.
  */
 
+@file:OptIn(ExperimentalMaterial3ExpressiveApi::class)
+
 package org.strongswan.android.ui.compose
 
 import org.strongswan.android.ui.compose.components.ShxSnackbarHost
@@ -53,11 +55,12 @@ import androidx.compose.material.icons.rounded.Refresh
 import androidx.compose.material.icons.rounded.Route
 import androidx.compose.material.icons.rounded.Rule
 import androidx.compose.material3.AlertDialog
-import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.LoadingIndicator
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
-import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.LinearWavyProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Scaffold
@@ -328,7 +331,7 @@ private fun RoutingContent(snackbarHostState: SnackbarHostState)
 				)
 				if (ruState.status == RuIpListStatus.UPDATING)
 				{
-					LinearProgressIndicator(
+					LinearWavyProgressIndicator(
 						Modifier
 							.fillMaxWidth()
 							.padding(horizontal = 16.dp, vertical = 4.dp),
@@ -586,7 +589,7 @@ private fun RuToggleRow(
 		}
 		if (updating)
 		{
-			CircularProgressIndicator(Modifier.size(14.dp), strokeWidth = 2.dp)
+			LoadingIndicator(Modifier.size(14.dp))
 			Spacer(Modifier.width(12.dp))
 		}
 		else

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

@@ -11,14 +11,14 @@ package org.strongswan.android.ui.compose
 
 import android.content.Intent
 import androidx.activity.ComponentActivity
+import androidx.activity.compose.BackHandler
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.compose.animation.AnimatedContent
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
-import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.scaleIn
-import androidx.compose.animation.slideOutHorizontally
 import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Column
@@ -44,7 +44,11 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.NavigationBarItemDefaults
 import androidx.compose.material3.NavigationDrawerItemDefaults
 import androidx.compose.material3.NavigationRailItemDefaults
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Surface
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.foundation.layout.Box
+import org.strongswan.android.ui.compose.components.ShxSnackbarHost
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteItemColors
@@ -105,6 +109,12 @@ fun ShxApp(viewModel: HomeViewModel = viewModel())
 	var pendingShare by remember { mutableStateOf<VpnProfile?>(null) }
 	val shareProfile: (VpnProfile) -> Unit = { pendingShare = it }
 
+	val snackbarHostState = remember { SnackbarHostState() }
+	LaunchedEffect(viewModel)
+	{
+		viewModel.messages.collect { snackbarHostState.showSnackbar(context.getString(it)) }
+	}
+
 	/* the home list keeps its scroll state across tab switches */
 	val homeListState = rememberLazyListState()
 
@@ -112,6 +122,13 @@ fun ShxApp(viewModel: HomeViewModel = viewModel())
 	 * and on tablets (Stage 3 of ui-ux-plan).  Item colors are built here in a
 	 * composable context - the items lambda itself does not compose. */
 	val navItemColors = shxNavigationItemColors()
+	val fadeSpec = MaterialTheme.motionScheme.defaultEffectsSpec<Float>()
+	val scaleSpec = MaterialTheme.motionScheme.defaultSpatialSpec<Float>()
+
+	/* from any other tab "back" returns to Connect instead of leaving the app */
+	BackHandler(enabled = state.tab != ShxTab.HOME) {
+		viewModel.setTab(ShxTab.HOME)
+	}
 	NavigationSuiteScaffold(
 		navigationSuiteItems = {
 			ShxNavigationSuiteItems(selected = state.tab, onSelect = viewModel::setTab, colors = navItemColors)
@@ -122,13 +139,16 @@ fun ShxApp(viewModel: HomeViewModel = viewModel())
 			modifier = Modifier.fillMaxSize(),
 			color = MaterialTheme.colorScheme.background,
 		) {
+			Box(Modifier.fillMaxSize())
+			{
 			AnimatedContent(
 				targetState = state.tab,
 				transitionSpec = {
-					val forward = targetState.ordinal >= initialState.ordinal
+					/* tabs are not spatially ordered: fade-through (outgoing fades out
-					val direction = if (forward) 1 else -1
+					 * first, incoming fades in with a slight scale), driven by the
-					(slideInHorizontally(tween(240)) { it / 6 * direction } + fadeIn(tween(240))) togetherWith
+					 * expressive motion scheme */
-						(slideOutHorizontally(tween(180)) { -it / 6 * direction } + fadeOut(tween(160)))
+					(fadeIn(fadeSpec) + scaleIn(scaleSpec, initialScale = 0.96f)) togetherWith
+						fadeOut(tween(90))
 				},
 				label = "tabContent",
 			) { tab ->
@@ -159,6 +179,11 @@ fun ShxApp(viewModel: HomeViewModel = viewModel())
 					ShxTab.ROUTING -> RoutingScreen()
 					ShxTab.SETTINGS -> SettingsScreen(profiles = state.profiles)
 				}
+			}
+			ShxSnackbarHost(
+				hostState = snackbarHostState,
+				modifier = Modifier.align(Alignment.BottomCenter),
+			)
 			}
 				pendingShare?.let { profile ->
 					ShareProfileDialog(