From 16b73c4373f55d5e495be03b8d511ec4198a90ec Mon Sep 17 00:00:00 2001
From: meyou <2636699780@qq.com>
Date: Sat, 16 May 2026 15:58:12 +0800
Subject: [PATCH] Fix flash when expanding after navigating months in collapsed
 state

Sync CalendarPager's pagerState to selectedDate in CalendarMonthView
via LaunchedEffect(selectedDate), so the page is already correct when
CalendarPager re-enters composition during expand. Remove the now-
redundant LaunchedEffect(Unit) sync in CalendarPager.
---
 .../plus/rua/project/ui/CalendarMonthView.kt       | 14 ++++++++++++++
 .../kotlin/plus/rua/project/ui/CalendarPager.kt    | 11 -----------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarMonthView.kt b/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarMonthView.kt
index ce3c726..5e66966 100644
--- a/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarMonthView.kt
+++ b/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarMonthView.kt
@@ -9,6 +9,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableIntStateOf
@@ -61,6 +62,19 @@ fun CalendarMonthView(
 
     val pagerState = rememberPagerState(initialPage = START_PAGE, pageCount = { Int.MAX_VALUE })
 
+    // 折叠态 WeekPager 切月时，持续同步 CalendarPager 的 pagerState，
+    // 避免展开时 CalendarPager 首帧显示旧月份导致闪白
+    LaunchedEffect(viewModel.selectedDate) {
+        @Suppress("DEPRECATION") // monthNumber 无替代 API
+        val targetPage = yearMonthToPage(
+            viewModel.selectedDate.year, viewModel.selectedDate.month.number,
+            today.year, today.month.number
+        )
+        if (targetPage != pagerState.currentPage) {
+            pagerState.scrollToPage(targetPage)
+        }
+    }
+
     val collapseProgress = viewModel.collapseProgress
     val headerHeightPx = monthHeaderHeightPx + weekdayHeaderHeightPx
     val rowPaddingPx = with(density) { ROW_PADDING_DP.dp.toPx() }.toInt()
diff --git a/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarPager.kt b/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarPager.kt
index 6d96511..1d29e21 100644
--- a/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarPager.kt
+++ b/shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarPager.kt
@@ -52,17 +52,6 @@ fun CalendarPager(
     val initialMonth = remember { today.month.number }
     val coroutineScope = rememberCoroutineScope()
 
-    // 展开后同步页面到 selectedDate 所在月份（修复折叠态切月后展开闪跳）
-    LaunchedEffect(Unit) {
-        @Suppress("DEPRECATION") // monthNumber 无替代 API
-        val targetPage = yearMonthToPage(
-            selectedDate.year, selectedDate.month.number, initialYear, initialMonth
-        )
-        if (targetPage != pagerState.currentPage) {
-            pagerState.scrollToPage(targetPage)
-        }
-    }
-
     // 跳过初始发射，保留首次渲染时的"今天"选中状态
     LaunchedEffect(pagerState) {
         snapshotFlow { pagerState.settledPage }.drop(1).collect { page ->