Add a callback for dismiss, notifying the caller to perform logic, such as animation.

lib/src/side_sheet_entry.dart

@@ -33,6 +33,8 @@ class SideSheetEntry<T> {
   /// A decoration widget builder which helps creating custom design.
   final DecorationBuilder? decorationBuilder;
 
+  final Function? dismissCallback;
+
   SideSheetEntry({
     required this.id,
     required this.index,
@@ -43,6 +45,7 @@ class SideSheetEntry<T> {
     required this.position,
     required this.dismissible,
     required this.decorationBuilder,
+    this.dismissCallback,
   });
 
   factory SideSheetEntry.createNewElement({
@@ -58,6 +61,7 @@ class SideSheetEntry<T> {
     required bool dismissible,
     required int index,
     bool initWithAnimation = true,
+    Function? dismissCB,
   }) {
     final key = UniqueKey();
 
@@ -85,6 +89,7 @@ class SideSheetEntry<T> {
       position: position,
       dismissible: dismissible,
       decorationBuilder: decorationBuilder,
+      dismissCallback: dismissCB,
     );
   }
 

lib/src/side_sheet_host.dart

@@ -112,6 +112,7 @@ class NestedSideSheetState extends State<NestedSideSheet>
     bool dismissible = true,
     Duration? animationDuration,
     Duration? reverseAnimationDuration,
+    Function? dismissCallback,
   }) async {
     if (!mounted || _blockGestures) return null;
     final completer = Completer<T?>();
@@ -127,6 +128,7 @@ class NestedSideSheetState extends State<NestedSideSheet>
       dismissible: dismissible,
       animationDuration: _setSettleDuration(animationDuration),
       reverseDuration: _setReverseSettleDuration(reverseAnimationDuration),
+      dismissCB: dismissCallback,
     );
     _sheetEntries.add(newEntry);
     _notifyStateChange();
@@ -155,6 +157,7 @@ class NestedSideSheetState extends State<NestedSideSheet>
       if (_sheetEntries.last != entry) {
         _removeSheetSilently(entry);
       }
+      entry.dismissCallback?.call();
     }
 
     _notifyStateChange();