From a5ad07a048857efca972cd30c3bc44ee39445980 Mon Sep 17 00:00:00 2001
From: gaoxin <gaoxin07@corp.netease.com>
Date: Wed, 27 Jul 2022 19:51:02 +0800
Subject: [PATCH] Add pageSnapping option for customizing horizontal scroll

---
 lib/src/table_calendar.dart        | 5 +++++
 lib/src/table_calendar_base.dart   | 3 +++
 lib/src/widgets/calendar_core.dart | 3 +++
 3 files changed, 11 insertions(+)

diff --git a/lib/src/table_calendar.dart b/lib/src/table_calendar.dart
index 3f083166..19465164 100644
--- a/lib/src/table_calendar.dart
+++ b/lib/src/table_calendar.dart
@@ -96,6 +96,9 @@ class TableCalendar<T> extends StatefulWidget {
   /// if the currently visible calendar page is changed.
   final bool pageAnimationEnabled;
 
+  /// Set to false to disable horizontal page snapping, useful for custom scroll behavior.
+  final bool pageSnapping;
+
   /// When set to true, `CalendarFormat.month` will always display six weeks,
   /// even if the content would fit in less.
   final bool sixWeekMonthsEnforced;
@@ -225,6 +228,7 @@ class TableCalendar<T> extends StatefulWidget {
     this.daysOfWeekVisible = true,
     this.pageJumpingEnabled = false,
     this.pageAnimationEnabled = true,
+    this.pageSnapping = true,
     this.sixWeekMonthsEnforced = false,
     this.shouldFillViewport = false,
     this.weekNumbersVisible = false,
@@ -502,6 +506,7 @@ class _TableCalendarState<T> extends State<TableCalendar<T>> {
             pageAnimationCurve: widget.pageAnimationCurve,
             availableCalendarFormats: widget.availableCalendarFormats,
             simpleSwipeConfig: widget.simpleSwipeConfig,
+            pageSnapping: widget.pageSnapping,
             sixWeekMonthsEnforced: widget.sixWeekMonthsEnforced,
             onVerticalSwipe: _swipeCalendarFormat,
             onPageChanged: (focusedDay) {
diff --git a/lib/src/table_calendar_base.dart b/lib/src/table_calendar_base.dart
index 7fe150f1..6222880c 100644
--- a/lib/src/table_calendar_base.dart
+++ b/lib/src/table_calendar_base.dart
@@ -25,6 +25,7 @@ class TableCalendarBase extends StatefulWidget {
   final TableBorder? tableBorder;
   final Duration formatAnimationDuration;
   final Curve formatAnimationCurve;
+  final bool pageSnapping;
   final bool pageAnimationEnabled;
   final Duration pageAnimationDuration;
   final Curve pageAnimationCurve;
@@ -55,6 +56,7 @@ class TableCalendarBase extends StatefulWidget {
     this.tableBorder,
     this.formatAnimationDuration = const Duration(milliseconds: 200),
     this.formatAnimationCurve = Curves.linear,
+    this.pageSnapping = true,
     this.pageAnimationEnabled = true,
     this.pageAnimationDuration = const Duration(milliseconds: 300),
     this.pageAnimationCurve = Curves.easeOut,
@@ -209,6 +211,7 @@ class _TableCalendarBaseState extends State<TableCalendarBase> {
               scrollPhysics: _canScrollHorizontally
                   ? PageScrollPhysics()
                   : NeverScrollableScrollPhysics(),
+              pageSnapping: widget.pageSnapping,
               firstDay: widget.firstDay,
               lastDay: widget.lastDay,
               startingDayOfWeek: widget.startingDayOfWeek,
diff --git a/lib/src/widgets/calendar_core.dart b/lib/src/widgets/calendar_core.dart
index aa7ffd00..88c0db6a 100644
--- a/lib/src/widgets/calendar_core.dart
+++ b/lib/src/widgets/calendar_core.dart
@@ -31,6 +31,7 @@ class CalendarCore extends StatelessWidget {
   final PageController? pageController;
   final ScrollPhysics? scrollPhysics;
   final _OnCalendarPageChanged onPageChanged;
+  final bool pageSnapping;
 
   const CalendarCore({
     Key? key,
@@ -55,6 +56,7 @@ class CalendarCore extends StatelessWidget {
     this.rowDecoration,
     this.tableBorder,
     this.scrollPhysics,
+    this.pageSnapping = true,
   })  : assert(!dowVisible || (dowHeight != null && dowBuilder != null)),
         super(key: key);
 
@@ -63,6 +65,7 @@ class CalendarCore extends StatelessWidget {
     return PageView.builder(
       controller: pageController,
       physics: scrollPhysics,
+      pageSnapping: pageSnapping,
       itemCount: _getPageCount(calendarFormat, firstDay, lastDay),
       itemBuilder: (context, index) {
         final baseDay = _getBaseDay(calendarFormat, index);