SplitViewController: add weights setter and notify changes

lib/split_view.dart

@@ -3,6 +3,7 @@ library split_view;
 import 'dart:collection';
 import 'dart:math';
 
+import 'package:collection/collection.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
@@ -74,8 +75,38 @@ class _SplitViewState extends State<SplitView> {
   void initState() {
     super.initState();
 
-    _controller =
-        widget.controller != null ? widget.controller! : SplitViewController();
+    _controller = widget.controller ?? SplitViewController();
+    _controller.addListener(_handleWeightsChange);
+  }
+
+  @override
+  void dispose() {
+    _controller.removeListener(_handleWeightsChange);
+    if (widget.controller == null) {
+      _controller.dispose();
+    }
+
+    super.dispose();
+  }
+
+  @override
+  void didUpdateWidget(SplitView oldWidget) {
+    super.didUpdateWidget(oldWidget);
+
+    if (widget.controller != oldWidget.controller) {
+      oldWidget.controller?.removeListener(_handleWeightsChange);
+      widget.controller?.addListener(_handleWeightsChange);
+
+      if (oldWidget.controller != null && widget.controller == null) {
+        _controller = SplitViewController(
+          weights: _controller.weights,
+          limits: _controller.limits,
+        );
+      } else if (widget.controller != null && oldWidget.controller == null) {
+        _controller.dispose();
+        _controller = widget.controller!;
+      }
+    }
   }
 
   @override
@@ -284,14 +315,16 @@ class _SplitViewState extends State<SplitView> {
       }
       newWeight1 = _startWeight1 + _startWeight2 - newWeight2;
     }
-    setState(() {
-      _controller._weights[index] = newWeight1;
-      _controller._weights[index + 1] = newWeight2;
-    });
 
-    if (widget.onWeightChanged != null) {
-      widget.onWeightChanged!(_controller.weights);
-    }
+    final weights = List.of(_controller._weights);
+    weights[index] = newWeight1;
+    weights[index + 1] = newWeight2;
+    _controller.weights = weights;
+  }
+
+  void _handleWeightsChange() {
+    setState(() {/* build() uses _controller.weights */});
+    widget.onWeightChanged?.call(_controller.weights);
   }
 
   Offset _getLocalPosition(BuildContext context, Offset pos) {
@@ -307,9 +340,14 @@ class _SplitViewState extends State<SplitView> {
 }
 
 /// Controller for [Splitview]
-class SplitViewController {
+class SplitViewController extends ChangeNotifier {
   /// Specifies the weight of each views.
   UnmodifiableListView<double?> get weights => UnmodifiableListView(_weights);
+  set weights(List<double?> weights) {
+    if (const ListEquality().equals(_weights, weights)) return;
+    _weights = weights;
+    notifyListeners();
+  }
 
   /// Specifies the limits of each views.
   UnmodifiableListView<WeightLimit?> get limits =>

pubspec.yaml

@@ -7,6 +7,7 @@ environment:
   sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
+  collection: ^1.16.0
   flutter:
     sdk: flutter
 

test/split_view_test.dart

@@ -1,11 +1,38 @@
+import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:split_view/split_view.dart';
 
 void main() {
-  test('adds one to input values', () {
-//    final calculator = Calculator();
-//    expect(calculator.addOne(2), 3);
-//    expect(calculator.addOne(-7), -6);
-//    expect(calculator.addOne(0), 1);
-//    expect(() => calculator.addOne(null), throwsNoSuchMethodError);
+  testWidgets('controller', (tester) async {
+    final controller = SplitViewController(weights: [0.1, 0.3, 0.6]);
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: SplitView(
+            gripSize: 10,
+            controller: controller,
+            viewMode: SplitViewMode.Horizontal,
+            children: [
+              Container(key: ValueKey(0)),
+              Container(key: ValueKey(1)),
+              Container(key: ValueKey(2)),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    final totalWidth = tester.getSize(find.byType(SplitView)).width - 2 * 10;
+
+    expect(tester.getSize(find.byKey(ValueKey(0))).width, totalWidth * 0.1);
+    expect(tester.getSize(find.byKey(ValueKey(1))).width, totalWidth * 0.3);
+    expect(tester.getSize(find.byKey(ValueKey(2))).width, totalWidth * 0.6);
+
+    controller.weights = [0.1, 0.4, 0.5];
+    await tester.pump();
+
+    expect(tester.getSize(find.byKey(ValueKey(0))).width, totalWidth * 0.1);
+    expect(tester.getSize(find.byKey(ValueKey(1))).width, totalWidth * 0.4);
+    expect(tester.getSize(find.byKey(ValueKey(2))).width, totalWidth * 0.5);
   });
 }