feat(android): toggle month view between scroll feed and paged swipe

New device-local setting "Monatsansicht seitenweise wischen" (SettingsStore,
no server sync). When off, the month view stays the continuous vertical scroll
feed. When on, it becomes a HorizontalPager — one month per screen, six
height-filling week rows, swipe left/right to change month. The prev/next/today
signals route to the pager (animateScrollToPage) instead of the list, and the
visible month is derived from pagerState.currentPage. WeekRow now takes a
rowModifier so the same row renders at a fixed height (scroll) or weight(1f)
(paged). Setting is re-read when the settings screen closes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/java/com/scarriffle/calendarr/data/SettingsStore.kt

@@ -62,6 +62,12 @@ class SettingsStore @Inject constructor(
         get() = prefs.getInt(K_CACHE_MONTHS, 3)
         set(value) = prefs.edit().putInt(K_CACHE_MONTHS, value).apply()
 
+    /** Device-local: month view as horizontal paged (swipe) instead of the
+     *  continuous vertical scroll feed (default false = scroll). */
+    var monthViewPaged: Boolean
+        get() = prefs.getBoolean(K_MONTH_PAGED, false)
+        set(value) = prefs.edit().putBoolean(K_MONTH_PAGED, value).apply()
+
     // --- Hidden calendars ("source:id") ---
 
     var hiddenCalendarKeys: Set<String>
@@ -99,6 +105,7 @@ class SettingsStore @Inject constructor(
         const val K_DEFAULT_REMINDER = "default_reminder_minutes"
         const val K_DEFAULT_DURATION = "default_event_duration_minutes"
         const val K_CACHE_MONTHS = "cache_months"
+        const val K_MONTH_PAGED = "month_view_paged"
         const val K_HIDDEN = "hidden_calendar_keys"
         const val K_BANISHED = "banished_calendar_keys"
         const val K_REMINDER_DISABLED = "reminder_disabled_calendar_keys"

app/src/main/java/com/scarriffle/calendarr/ui/L10n.kt

@@ -63,6 +63,7 @@ object L10n {
             "settings.calview" to "Kalenderansicht", "settings.defaultview" to "Standardansicht",
             "settings.firstweekday" to "Erster Wochentag", "settings.monday" to "Montag",
             "settings.sunday" to "Sonntag", "settings.dimpast" to "Vergangene Termine ausgrauen",
+            "settings.month_paged" to "Monatsansicht seitenweise wischen",
             "settings.hourheight" to "Stundenhöhe",
             "settings.hourheight.compact" to "Kompakt", "settings.hourheight.normal" to "Normal",
             "settings.hourheight.comfort" to "Komfort", "settings.hourheight.large" to "Gross",
@@ -208,6 +209,7 @@ object L10n {
             "settings.calview" to "Calendar view", "settings.defaultview" to "Default view",
             "settings.firstweekday" to "First day of week", "settings.monday" to "Monday",
             "settings.sunday" to "Sunday", "settings.dimpast" to "Dim past events",
+            "settings.month_paged" to "Swipe month view as pages",
             "settings.hourheight" to "Hour height",
             "settings.hourheight.compact" to "Compact", "settings.hourheight.normal" to "Normal",
             "settings.hourheight.comfort" to "Comfort", "settings.hourheight.large" to "Large",

app/src/main/java/com/scarriffle/calendarr/ui/calendar/CalendarScreen.kt

@@ -299,7 +299,7 @@ fun CalendarScreen(
     when (overlay) {
         Overlay.PROFILE -> ProfileScreen(onClose = { overlay = Overlay.NONE })
         Overlay.SETTINGS -> SettingsScreen(
-            onClose = { overlay = Overlay.NONE },
+            onClose = { overlay = Overlay.NONE; vm.refreshMonthViewMode() },
             onSettingsChanged = onSettingsChanged,
             onSettingsSynced = onSettingsSynced,
         )

app/src/main/java/com/scarriffle/calendarr/ui/calendar/CalendarViewModel.kt

@@ -58,6 +58,8 @@ data class CalendarUiState(
     // Full calendar list across all sources (loaded on demand) so the filter
     // shows every calendar, including ones with no events in the loaded range.
     val allCalendars: List<CalendarFilterEntry> = emptyList(),
+    // Device-local: month view as horizontal paged (swipe) vs. scroll feed.
+    val monthViewPaged: Boolean = false,
 )
 
 fun groupMemberKey(ownerId: Int): String = "gm:$ownerId"
@@ -122,9 +124,15 @@ class CalendarViewModel @Inject constructor(
             hiddenKeys = settingsStore.hiddenCalendarKeys,
             banishedKeys = settingsStore.banishedCalendarKeys,
             reminderDisabledKeys = settingsStore.reminderDisabledCalendarKeys,
+            monthViewPaged = settingsStore.monthViewPaged,
         )
     }
 
+    /** Re-read the device-local month-view mode (called when settings close). */
+    fun refreshMonthViewMode() {
+        _state.update { it.copy(monthViewPaged = settingsStore.monthViewPaged) }
+    }
+
     /** Default duration (minutes) for a new event's end time. */
     val defaultEventDurationMinutes: Int get() = settingsStore.loadSettings().defaultEventDurationMinutes
 

app/src/main/java/com/scarriffle/calendarr/ui/calendar/MonthView.kt

@@ -16,6 +16,8 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.foundation.pager.HorizontalPager
+import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
@@ -79,7 +81,10 @@ private data class PlacedBar(
 
 private class WeekLayout(val bars: List<PlacedBar>, val overflowPerCol: IntArray)
 
-/** Continuous, vertically scrolling month calendar with multi-day event bars (iOS-style). */
+/** Month calendar with multi-day event bars (iOS-style). Two modes: a
+ *  continuous vertical scroll feed, or a horizontally-paged one-month-per-screen
+ *  grid (swipe left/right), toggled by [CalendarUiState.monthViewPaged]. */
+@OptIn(ExperimentalFoundationApi::class)
 @Composable
 fun MonthView(
     state: CalendarUiState,
@@ -127,6 +132,39 @@ fun MonthView(
 
     val todayIndex = remember(firstVisible) { weekIndexOf(today) }
 
+    // Month-paged mode bookkeeping (one page per calendar month).
+    val firstMonth = remember { today.withDayOfMonth(1).minusMonths(MONTHS_BACK) }
+    val monthCount = remember { (MONTHS_BACK + MONTHS_AHEAD + 1).toInt() }
+    fun monthIndexOf(date: LocalDate): Int =
+        ChronoUnit.MONTHS.between(firstMonth, date.withDayOfMonth(1)).toInt().coerceIn(0, monthCount - 1)
+    val todayMonthIndex = remember(firstMonth) { monthIndexOf(today) }
+    val pagerState = rememberPagerState(initialPage = todayMonthIndex) { monthCount }
+
+    val eventsByWeek = remember(state.events, mondayFirst) { buildEventsByWeek(state.events, mondayFirst) }
+    val dimPast = settings.dimPastEvents
+    val cwLabel = tr("cal.cw")
+    // remember: a fresh Instant per recomposition would invalidate every visible
+    // WeekRow (the main source of scroll jank); minute precision is plenty here.
+    val now = remember { java.time.Instant.now() }
+
+    // Route the title / prev-next / today signals to the active surface (pager or list).
+    if (state.monthViewPaged) {
+        LaunchedEffect(scrollToTodaySignal) {
+            if (scrollToTodaySignal > 0) pagerState.animateScrollToPage(todayMonthIndex)
+        }
+        LaunchedEffect(monthJumpSignal) {
+            if (monthJumpSignal > 0 && monthJumpTarget != null) pagerState.animateScrollToPage(monthIndexOf(monthJumpTarget))
+        }
+        LaunchedEffect(pagerState) {
+            snapshotFlow { pagerState.currentPage }
+                .map { firstMonth.plusMonths(it.toLong()) }
+                .distinctUntilChanged()
+                .collect { month ->
+                    onVisibleMonthChange(month)
+                    vm.ensureMonthLoaded(month)
+                }
+        }
+    } else {
         LaunchedEffect(Unit) { listState.scrollToItem((todayIndex - 1).coerceAtLeast(0)) }
         LaunchedEffect(scrollToTodaySignal) {
             if (scrollToTodaySignal > 0) listState.animateScrollToItem((todayIndex - 1).coerceAtLeast(0))
@@ -145,13 +183,7 @@ fun MonthView(
                     vm.ensureMonthLoaded(month)
                 }
         }
-
+    }
-    val eventsByWeek = remember(state.events, mondayFirst) { buildEventsByWeek(state.events, mondayFirst) }
-    val dimPast = settings.dimPastEvents
-    val cwLabel = tr("cal.cw")
-    // remember: a fresh Instant per recomposition would invalidate every visible
-    // WeekRow (the main source of scroll jank); minute precision is plenty here.
-    val now = remember { java.time.Instant.now() }
 
     Column(Modifier.fillMaxSize()) {
         Row(Modifier.fillMaxWidth().padding(vertical = 3.dp)) {
@@ -166,6 +198,40 @@ fun MonthView(
             }
         }
 
+        if (state.monthViewPaged) {
+            // One month per page, six height-filling week rows, swipe to change month.
+            HorizontalPager(
+                state = pagerState,
+                modifier = Modifier.fillMaxSize().onSizeChanged { gridWidthPx = it.width },
+            ) { page ->
+                val month = firstMonth.plusMonths(page.toLong())
+                val firstWeek = startOfWeek(month.withDayOfMonth(1), mondayFirst)
+                Column(Modifier.fillMaxSize()) {
+                    repeat(6) { w ->
+                        val weekStart = firstWeek.plusWeeks(w.toLong())
+                        WeekRow(
+                            rowModifier = Modifier.fillMaxWidth().weight(1f),
+                            weekStart = weekStart,
+                            today = today,
+                            weekEvents = eventsByWeek[weekStart] ?: emptyList(),
+                            cellW = cellW,
+                            dimPast = dimPast,
+                            now = now,
+                            lang = lang,
+                            cwLabel = cwLabel,
+                            dividerColor = dividerColor,
+                            gridColor = gridColor,
+                            labelColor = labelColor,
+                            secondaryText = secondaryText,
+                            todayColor = todayColor,
+                            onDayClick = onDayClick,
+                            onDayLongPress = onDayLongPress,
+                            onEventClick = onEventClick,
+                        )
+                    }
+                }
+            }
+        } else {
             LazyColumn(
                 state = listState,
                 modifier = Modifier.fillMaxSize().onSizeChanged { gridWidthPx = it.width },
@@ -173,6 +239,7 @@ fun MonthView(
                 items(weekCount, key = { it }, contentType = { "week" }) { index ->
                     val weekStart = firstVisible.plusWeeks(index.toLong())
                     WeekRow(
+                        rowModifier = Modifier.fillMaxWidth().height(ROW_HEIGHT),
                         weekStart = weekStart,
                         today = today,
                         weekEvents = eventsByWeek[weekStart] ?: emptyList(),
@@ -194,9 +261,11 @@ fun MonthView(
             }
         }
     }
+}
 
 @Composable
 private fun WeekRow(
+    rowModifier: Modifier,
     weekStart: LocalDate,
     today: LocalDate,
     weekEvents: List<CalEvent>,
@@ -220,7 +289,9 @@ private fun WeekRow(
 
     val packed = remember(weekStart, weekEvents) { packEvents(weekStart, weekEvents) }
 
-    Box(Modifier.fillMaxWidth().height(ROW_HEIGHT)) {
+    // Scroll mode passes a fixed ROW_HEIGHT; paged mode passes weight(1f) so six
+    // rows fill the screen. Event bars anchor to the top; the day cells fill height.
+    Box(rowModifier) {
         Row(Modifier.fillMaxSize()) {
             days.forEachIndexed { idx, day ->
                 val edge = when {

app/src/main/java/com/scarriffle/calendarr/ui/settings/SettingsScreen.kt

@@ -71,6 +71,7 @@ fun SettingsScreen(
     val initialSettings = LocalAppSettings.current
     var settings by remember { mutableStateOf(initialSettings) }
     var cacheMonths by remember { mutableStateOf(vm.cacheMonths) }
+    var monthPaged by remember { mutableStateOf(vm.monthViewPaged) }
 
     fun update(newSettings: AppSettings) {
         settings = newSettings
@@ -126,6 +127,12 @@ fun SettingsScreen(
                 }
                 Spacer(Modifier.size(16.dp))
 
+                Row(Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.SpaceBetween) {
+                    Text(tr("settings.month_paged"), style = MaterialTheme.typography.bodyLarge)
+                    Switch(checked = monthPaged, onCheckedChange = { monthPaged = it; vm.monthViewPaged = it })
+                }
+                Spacer(Modifier.size(16.dp))
+
                 Divider(Modifier.padding(vertical = 16.dp))
 
                 Section(tr("settings.language"))

app/src/main/java/com/scarriffle/calendarr/ui/settings/SettingsViewModel.kt

@@ -32,6 +32,11 @@ class SettingsViewModel @Inject constructor(
         get() = settingsStore.cacheMonths
         set(value) { settingsStore.cacheMonths = value }
 
+    /** Device-local: month view as horizontal paged (swipe) vs. scroll feed. */
+    var monthViewPaged: Boolean
+        get() = settingsStore.monthViewPaged
+        set(value) { settingsStore.monthViewPaged = value }
+
     // ---- Profile chapter (server-backed) ----
 
     var displayName by mutableStateOf("")