Adding id to be used as an internal Key and facilitating

reconfiguration of the layout while maintaining the state of the
widgets. #68

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 3.2.0
+
+* `Area`
+  * Adding `id` to be used as an internal Key and facilitating reconfiguration of the layout while maintaining the state of the widgets. 
+
 ## 3.1.0
 
 * `Area`
@@ -9,11 +14,11 @@
 
 ## 3.0.2
 
-Bug fix: Other Widgets visually behind are not receiving mouse events.
+Bugfix: Other Widgets visually behind are not receiving mouse events.
 
 ## 3.0.1
 
-Bug fix: Stretching to recover the minimum size when space is available.
+Bugfix: Stretching to recover the minimum size when space is available.
 
 ## 3.0.0
 
@@ -30,7 +35,7 @@ Bug fix: Stretching to recover the minimum size when space is available.
 * `MultiSplitView`
   * Width and height configuration to be used in an unbounded situation.
 * Setting the widget directly in the area or through builders.
-* Bug fix
+* Bugfix
   * Area using the child widget key.
 
 ## 2.4.0

lib/src/area.dart

@@ -1,6 +1,5 @@
 import 'dart:math' as math;
 
-import 'package:flutter/material.dart';
 import 'package:meta/meta.dart';
 import 'package:multi_split_view/src/area_widget_builder.dart';
 import 'package:multi_split_view/src/internal/num_util.dart';
@@ -25,9 +24,11 @@ class Area {
       double? flex,
       double? min,
       double? max,
+      dynamic id,
       this.data,
       this.builder})
-      : _size = size,
+      : this.id = id != null ? id : _AreaId(),
+        _size = size,
         _flex = flex,
         _min = min,
         _max = max {
@@ -87,18 +88,17 @@ class Area {
   /// Any data associated with the area.
   dynamic data;
 
-  UniqueKey _key = UniqueKey();
+  /// Used as an internal Key and facilitates reconfiguration of the layout
+  /// while maintaining the state of the widget.
+  /// It will never be null and must be unique in the layout.
+  final dynamic id;
 
   /// The widget builder.
   AreaWidgetBuilder? builder;
 }
 
 @internal
 class AreaHelper {
-  static Key keyFrom({required Area area}) {
-    return area._key;
-  }
-
   /// Sets the area flex value.
   static void setFlex({required Area area, required double flex}) {
     flex = NumUtil.fix('flex', flex);
@@ -134,3 +134,11 @@ class AreaHelper {
     area._index = index;
   }
 }
+
+/// Default area id object
+class _AreaId {
+  @override
+  String toString() {
+    return 'area id: $hashCode';
+  }
+}

lib/src/controller.dart

@@ -28,7 +28,9 @@ class MultiSplitViewController extends ChangeNotifier {
 
   /// Allows to automatically set a new value for the data attribute of the [Area].
   AreaDataModifier? _areaDataModifier;
+
   AreaDataModifier? get areaDataModifier => _areaDataModifier;
+
   set areaDataModifier(AreaDataModifier? modifier) {
     if (_areaDataModifier != modifier) {
       _areaDataModifier = modifier;
@@ -39,9 +41,11 @@ class MultiSplitViewController extends ChangeNotifier {
   Object _areasUpdateHash = Object();
 
   double _flexCount = 0;
+
   double get flexCount => _flexCount;
 
   double _totalFlex = 0;
+
   double get totalFlex => _totalFlex;
 
   /// Applies the current data modifier.
@@ -57,12 +61,17 @@ class MultiSplitViewController extends ChangeNotifier {
   /// Updates the areas.
   /// Changes the flex to 1 if the total flex of the areas is 0.
   void _updateAreas() {
+    Set<dynamic> ids = {};
+
     _areasUpdateHash = Object();
 
     _totalFlex = 0;
     _flexCount = 0;
     int index = 0;
     for (Area area in _areas) {
+      if (!ids.add(area.id)) {
+        throw StateError('Area with duplicate id.');
+      }
       AreaHelper.setIndex(area: area, index: index);
       if (area.flex != null) {
         _totalFlex += area.flex!;

lib/src/multi_split_view.dart

@@ -228,9 +228,7 @@ class _MultiSplitViewState extends State<MultiSplitView> {
                 ? HitTestBehavior.opaque
                 : HitTestBehavior.translucent);
         children.add(LayoutId(
-            key: AreaHelper.keyFrom(area: area),
-            id: index,
-            child: ClipRect(child: child)));
+            key: ValueKey(area.id), id: index, child: ClipRect(child: child)));
 
         //divisor widget
         if (index < _controller.areasCount - 1) {