Show month agenda by default in split view (#142)

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+- **Split view opens with the month's agenda.** It starts at today in the current month; tapping a day filters the list, and the filter chip restores the full month. Swiping the list moves by day when filtered and by month otherwise ([#142]).
+
 ## [2.21.0] — 2026-09-23
 
 ### Added

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthScreen.kt

@@ -4,6 +4,7 @@ import androidx.activity.compose.BackHandler
 import androidx.compose.animation.AnimatedContent
 import androidx.compose.animation.EnterExitState
 import androidx.compose.foundation.gestures.detectVerticalDragGestures
+import androidx.compose.foundation.gestures.detectHorizontalDragGestures
 import androidx.compose.foundation.pager.HorizontalPager
 import androidx.compose.foundation.pager.PagerDefaults
 import androidx.compose.foundation.pager.PagerState
@@ -55,10 +56,12 @@ import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.selection.selectable
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Menu
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material3.DrawerValue
@@ -66,6 +69,7 @@ import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.InputChip
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ModalNavigationDrawer
 import androidx.compose.material3.Scaffold
@@ -148,6 +152,7 @@ import de.jeanlucmakiola.calendula.domain.hasEnded
 import de.jeanlucmakiola.calendula.ui.agenda.AgendaDayHeader
 import de.jeanlucmakiola.calendula.ui.agenda.AgendaEmptyDayRow
 import de.jeanlucmakiola.calendula.ui.agenda.AgendaEventRow
+import de.jeanlucmakiola.calendula.ui.agenda.agendaDayLabel
 import de.jeanlucmakiola.calendula.ui.common.formatCalendarTitle
 import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
 import de.jeanlucmakiola.calendula.ui.common.AppBarSpacing
@@ -429,6 +434,7 @@ fun MonthScreen(
                         onCreateEvent(
                             when {
                                 viewStyle == MonthViewStyle.Split -> selectedDate
+                                    ?: if (isOnCurrentMonth) today else LocalDate(titleMonth.year, titleMonth.month, 1)
                                 isOnCurrentMonth -> today
                                 else -> LocalDate(titleMonth.year, titleMonth.month, 1)
                             },
@@ -473,6 +479,9 @@ fun MonthScreen(
                             weekStart = weekStart,
                             monthState = viewModel::month,
                             showWeekNumbers = showWeekNumbers,
+                            onPaneSwipeNext = { viewModel.stepSplitPane(1) },
+                            onPaneSwipePrev = { viewModel.stepSplitPane(-1) },
+                            onClearSelection = viewModel::clearSelection,
                             onRetry = jumpToToday,
                             // A tapped leading/trailing day follows to its own
                             // month, pager and all — straight away, or a swipe
@@ -1293,11 +1302,14 @@ private val MONTH_EXPAND_THRESHOLD = 48.dp
 @Composable
 private fun SplitMonthContent(
     state: MonthUiState,
-    selected: LocalDate,
+    selected: LocalDate?,
     pagerState: PagerState,
     weekStart: DayOfWeek,
     monthState: (YearMonth, DayOfWeek) -> StateFlow<MonthUiState>,
     showWeekNumbers: Boolean,
+    onPaneSwipeNext: () -> Unit,
+    onPaneSwipePrev: () -> Unit,
+    onClearSelection: () -> Unit,
     onRetry: () -> Unit,
     onSelectDay: (LocalDate) -> Unit,
     onOpenDay: (LocalDate) -> Unit,
@@ -1373,6 +1385,9 @@ private fun SplitMonthContent(
                             showWeekNumbers = showWeekNumbers,
                             expandDrag = expandDrag,
                             onSelectDay = onSelectDay,
+                            onPaneSwipeNext = onPaneSwipeNext,
+                            onPaneSwipePrev = onPaneSwipePrev,
+                            onClearSelection = onClearSelection,
                             onOpenDay = onOpenDay,
                             onEventClick = onEventClick,
                             onCreateEvent = onCreateEvent,
@@ -1398,10 +1413,13 @@ private class SplitMonths(
 private fun SplitMonthCollapsed(
     state: MonthUiState.Success,
     months: SplitMonths,
-    selected: LocalDate,
+    selected: LocalDate?,
     showWeekNumbers: Boolean,
     expandDrag: Modifier,
     onSelectDay: (LocalDate) -> Unit,
+    onPaneSwipeNext: () -> Unit,
+    onPaneSwipePrev: () -> Unit,
+    onClearSelection: () -> Unit,
     onOpenDay: (LocalDate) -> Unit,
     onEventClick: (EventInstance) -> Unit,
     onCreateEvent: (LocalDate) -> Unit,
@@ -1440,18 +1458,64 @@ private fun SplitMonthCollapsed(
             }
             SplitExpandHandle(expanded = false, onToggle = onExpand)
         }
-        SplitDayPane(
-            date = selected,
-            today = state.today,
-            // Null, not empty: the selection moves to the new month before
-            // its data arrives, and a missing key means "not loaded yet".
-            // Passing an empty list would claim the day was free.
-            events = state.instancesByDay[selected],
-            zone = state.zone,
-            onOpenDay = onOpenDay,
-            onEventClick = onEventClick,
-            onCreateEvent = onCreateEvent,
-            modifier = Modifier.weight(1f).fillMaxWidth(),
+        Box(
+            Modifier.weight(1f).fillMaxWidth()
+                .then(rememberSplitPaneSwipe(onPaneSwipeNext, onPaneSwipePrev)),
+        ) {
+            if (selected == null) {
+                SplitMonthAgendaPane(
+                    state = state,
+                    onOpenDay = onOpenDay,
+                    onEventClick = onEventClick,
+                    onCreateEvent = onCreateEvent,
+                )
+            } else {
+                Column {
+                    InputChip(
+                        selected = true,
+                        onClick = onClearSelection,
+                        label = { Text(agendaDayLabel(selected, state.today)) },
+                        trailingIcon = {
+                            Icon(
+                                Icons.Default.Close,
+                                contentDescription = stringResource(R.string.month_split_clear_filter),
+                            )
+                        },
+                        modifier = Modifier.padding(start = 16.dp),
+                    )
+                    SplitDayPane(
+                        date = selected,
+                        today = state.today,
+                        events = state.instancesByDay[selected],
+                        zone = state.zone,
+                        onOpenDay = onOpenDay,
+                        onEventClick = onEventClick,
+                        onCreateEvent = onCreateEvent,
+                        modifier = Modifier.weight(1f).fillMaxWidth(),
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun rememberSplitPaneSwipe(onNext: () -> Unit, onPrev: () -> Unit): Modifier {
+    val threshold = with(LocalDensity.current) { 24.dp.toPx() }
+    val currentNext by rememberUpdatedState(onNext)
+    val currentPrev by rememberUpdatedState(onPrev)
+    return Modifier.pointerInput(threshold) {
+        var distance = 0f
+        var fired = false
+        detectHorizontalDragGestures(
+            onDragStart = { distance = 0f; fired = false },
+            onHorizontalDrag = { _, drag ->
+                distance += drag
+                if (!fired && kotlin.math.abs(distance) >= threshold) {
+                    fired = true
+                    if (distance < 0f) currentNext() else currentPrev()
+                }
+            },
         )
     }
 }
@@ -1469,7 +1533,7 @@ private fun SplitMonthCollapsed(
 private fun SplitMonthExpanded(
     months: SplitMonths,
     /** Marked nowhere here; it only anchors the outline's morph. */
-    selected: LocalDate,
+    selected: LocalDate?,
     showWeekNumbers: Boolean,
     expandDrag: Modifier,
     onPickDay: (LocalDate) -> Unit,
@@ -1581,7 +1645,7 @@ private val SPLIT_HANDLE_ROW_HEIGHT = 24.dp
 @Composable
 internal fun SplitMonthGrid(
     state: MonthUiState.Success,
-    selected: LocalDate,
+    selected: LocalDate?,
     showWeekNumbers: Boolean,
     onSelectDay: (LocalDate) -> Unit,
     modifier: Modifier = Modifier,
@@ -1816,6 +1880,54 @@ private fun SplitDots(
     }
 }
 
+@OptIn(ExperimentalFoundationApi::class)
+@Composable
+private fun SplitMonthAgendaPane(
+    state: MonthUiState.Success,
+    onOpenDay: (LocalDate) -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateEvent: (LocalDate) -> Unit,
+) {
+    val start = agendaStartForMonth(state.month, state.today)
+    val days = state.instancesByDay.keys
+        .filter { it >= start && it.year == state.month.year && it.month == state.month.month }
+        .filter { state.instancesByDay[it].orEmpty().isNotEmpty() }
+        .toMutableList()
+        .apply { if (start !in this) add(start) }
+        .sorted()
+    val dimCutoff = LocalDimCutoff.current
+    val listState = key(state.month) { rememberLazyListState() }
+    LazyColumn(state = listState, contentPadding = PaddingValues(top = 8.dp, bottom = 96.dp)) {
+        days.forEach { day ->
+            val events = state.instancesByDay[day].orEmpty()
+            stickyHeader(key = "header-$day") {
+                AgendaDayHeader(date = day, today = state.today, onOpenDay = onOpenDay)
+            }
+            if (events.isEmpty()) {
+                item(key = "empty-$day") {
+                    AgendaEmptyDayRow(
+                        text = stringResource(R.string.month_split_no_events),
+                        onClick = { onCreateEvent(day) },
+                    )
+                }
+            } else {
+                itemsIndexed(events, key = { _, event -> "$day-${event.instanceId}" }) { index, event ->
+                    AgendaEventRow(
+                        event = event,
+                        day = day,
+                        zone = state.zone,
+                        position = positionOf(index, events.size),
+                        dimmed = dimCutoff != null && event.hasEnded(dimCutoff),
+                        modifier = animateItemMotion(),
+                        onClick = { onEventClick(event) },
+                    )
+                }
+            }
+            item(key = "gap-$day") { Spacer(Modifier.height(8.dp)) }
+        }
+    }
+}
+
 /**
  * The selected day's events, in the agenda's own row vocabulary so the two
  * surfaces read as one app. The date header opens the full Day view, matching

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthViewModel.kt

@@ -292,12 +292,10 @@ class MonthViewModel @Inject constructor(
 
     // --- Split style (#53) ------------------------------------------------
     //
-    // The first selected-day concept in the app: the other views drill straight
-    // into a date, while the split style keeps one selected and lists it below
-    // the grid.
+    // Null means the full-month agenda; a date narrows the pane to that day.
 
-    private val _selectedDate = MutableStateFlow(todayDate)
-    val selectedDate: StateFlow<LocalDate> = _selectedDate
+    private val _selectedDate = MutableStateFlow<LocalDate?>(null)
+    val selectedDate: StateFlow<LocalDate?> = _selectedDate
 
     /**
      * Select [date], following it to its month if it sits in the grid's leading
@@ -305,23 +303,33 @@ class MonthViewModel @Inject constructor(
      * silently list a date the grid isn't pointing at.
      */
     fun selectDate(date: LocalDate) {
-        _selectedDate.value = date
         val target = YearMonth(date.year, date.month)
+        _selectedDate.value = if (target == _month.value && _selectedDate.value == date) null else date
         if (target != _month.value) _month.value = target
     }
 
-    /**
-     * Move the selection with the month: today if the new month holds it, else
-     * its 1st. Leaving the old date selected would list a day the grid no longer
-     * shows.
-     */
+    fun clearSelection() { _selectedDate.value = null }
+
+    /** A pane swipe walks days when filtered, months when showing the agenda. */
+    fun stepSplitPane(days: Int) {
+        val selected = _selectedDate.value
+        if (selected == null) {
+            _month.value = yearMonthForIndex(monthIndexOf(_month.value) + days)
+        } else {
+            val next = selected.plus(days, DateTimeUnit.DAY)
+            _selectedDate.value = next
+            _month.value = YearMonth(next.year, next.month)
+        }
+    }
+
+    /** Moving the grid to another month restores its full agenda. */
     private fun realignSelection() {
-        _selectedDate.value = selectionForMonth(_month.value, todayDate)
+        _selectedDate.value = null
     }
 
     fun goToToday() {
         _month.value = YearMonth(todayDate.year, todayDate.month)
-        _selectedDate.value = todayDate
+        _selectedDate.value = null
     }
 
     /**
@@ -330,13 +338,12 @@ class MonthViewModel @Inject constructor(
      * otherwise sit wherever paged navigation last left it (today's month, on a
      * fresh open) — and a switch to a paged style, or a reseed of the other
      * scrolling style's list, would jump there instead of holding position. The
-     * selection is realigned alongside it so that landing on the Split style
-     * shows a live day in the month on screen rather than a stale, off-month one.
+     * selection is cleared alongside it so Split opens the visible month's agenda.
      */
     fun syncScrollMonth(ym: YearMonth) {
         if (_month.value == ym) return
         _month.value = ym
-        _selectedDate.value = selectionForMonth(ym, todayDate)
+        _selectedDate.value = null
     }
 
     /** Jump to the month containing [date] (drawer jump-to-date). */
@@ -544,11 +551,10 @@ private const val WINDOW_EDGE = 2
 internal fun edgeForPad(pad: Int): Int = minOf(WINDOW_EDGE, pad - 1).coerceAtLeast(0)
 
 /**
- * Which day the split style should select when the grid lands on [month]:
- * [today] when the month holds it, otherwise the 1st. Pure so the rule can be
- * tested without standing up a view model and a provider behind it.
+ * First day shown in the split agenda: today in the current month, otherwise
+ * the first of the visible month.
  */
-internal fun selectionForMonth(month: YearMonth, today: LocalDate): LocalDate =
+internal fun agendaStartForMonth(month: YearMonth, today: LocalDate): LocalDate =
     if (YearMonth(today.year, today.month) == month) {
         today
     } else {

app/src/main/res/values/strings.xml

@@ -55,6 +55,7 @@
     <string name="month_prev">Previous month</string>
     <string name="month_next">Next month</string>
     <string name="month_today_action">Today</string>
+    <string name="month_split_clear_filter">Show full month agenda</string>
     <string name="month_more_actions">More actions</string>
     <string name="month_open_menu">Open menu</string>
     <string name="month_action_settings">Settings</string>

app/src/test/java/de/jeanlucmakiola/calendula/ui/month/ContinuousMonthIndexTest.kt

@@ -222,17 +222,17 @@ class ContinuousMonthIndexTest {
     }
 
     @Test
-    fun `the split selection follows the month, landing on today when it's there`() {
+    fun `the split agenda starts at today in the current month`() {
         val today = LocalDate(2026, 6, 10)
-        assertThat(selectionForMonth(jun26, today)).isEqualTo(today)
+        assertThat(agendaStartForMonth(jun26, today)).isEqualTo(today)
     }
 
     @Test
-    fun `the split selection falls to the 1st of any other month`() {
+    fun `the split agenda starts at the 1st of another month`() {
         val today = LocalDate(2026, 6, 10)
-        assertThat(selectionForMonth(YearMonth(2026, Month.JULY), today))
+        assertThat(agendaStartForMonth(YearMonth(2026, Month.JULY), today))
             .isEqualTo(LocalDate(2026, 7, 1))
-        assertThat(selectionForMonth(YearMonth(2025, Month.JUNE), today))
+        assertThat(agendaStartForMonth(YearMonth(2025, Month.JUNE), today))
             .isEqualTo(LocalDate(2025, 6, 1))
     }
 }