add draggable_scrollable_controller

packages/flutter_hooks/lib/src/draggable_scrollable_controller.dart

@@ -0,0 +1,34 @@
+part of 'hooks.dart';
+
+/// Creates a [DraggableScrollableController] that will be disposed automatically.
+///
+/// See also:
+/// - [DraggableScrollableController]
+DraggableScrollableController useDraggableScrollableController(
+    {List<Object?>? keys}) {
+  return use(_DraggableScrollableControllerHook(keys: keys));
+}
+
+class _DraggableScrollableControllerHook
+    extends Hook<DraggableScrollableController> {
+  const _DraggableScrollableControllerHook({List<Object?>? keys})
+      : super(keys: keys);
+
+  @override
+  HookState<DraggableScrollableController, Hook<DraggableScrollableController>>
+      createState() => _DraggableScrollableControllerHookState();
+}
+
+class _DraggableScrollableControllerHookState extends HookState<
+    DraggableScrollableController, _DraggableScrollableControllerHook> {
+  final controller = DraggableScrollableController();
+
+  @override
+  String get debugLabel => 'useDraggableScrollableController';
+
+  @override
+  DraggableScrollableController build(BuildContext context) => controller;
+
+  @override
+  void dispose() => controller.dispose();
+}

packages/flutter_hooks/lib/src/hooks.dart

@@ -4,6 +4,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart'
     show
         Brightness,
+        DraggableScrollableController,
         ExpansionTileController,
         MaterialState,
         MaterialStatesController,
@@ -16,6 +17,7 @@ import 'framework.dart';
 
 part 'animation.dart';
 part 'async.dart';
+part 'draggable_scrollable_controller.dart';
 part 'expansion_tile_controller.dart';
 part 'focus_node.dart';
 part 'focus_scope_node.dart';

packages/flutter_hooks/test/use_draggable_scrollable_controller_test.dart

@@ -0,0 +1,134 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_hooks/src/framework.dart';
+import 'package:flutter_hooks/src/hooks.dart';
+
+import 'mock.dart';
+
+void main() {
+  testWidgets('debugFillProperties', (tester) async {
+    await tester.pumpWidget(
+      HookBuilder(builder: (context) {
+        useDraggableScrollableController();
+        return const SizedBox();
+      }),
+    );
+
+    await tester.pump();
+
+    final element = tester.element(find.byType(HookBuilder));
+
+    expect(
+      element
+          .toDiagnosticsNode(style: DiagnosticsTreeStyle.offstage)
+          .toStringDeep(),
+      equalsIgnoringHashCodes('HookBuilder\n'
+          ' │ useDraggableScrollableController: Instance of\n'
+          " │   'DraggableScrollableController'\n"
+          ' └SizedBox(renderObject: RenderConstrainedBox#00000)\n'),
+    );
+  });
+
+  group('useDraggableScrollableController', () {
+    testWidgets(
+        'controller functions correctly and initial values matches with real constructor',
+        (tester) async {
+      late DraggableScrollableController controller;
+      final controller2 = DraggableScrollableController();
+
+      await tester.pumpWidget(MaterialApp(
+        home: Scaffold(
+          body: HookBuilder(builder: (context) {
+            return Column(
+              children: [
+                ElevatedButton(
+                    onPressed: () {
+                      showBottomSheet(
+                          context: context,
+                          builder: (context) {
+                            // Using a builder here to ensure that the controller is
+                            // disposed when the sheet is closed.
+                            return HookBuilder(builder: (context) {
+                              controller = useDraggableScrollableController();
+                              return DraggableScrollableSheet(
+                                controller: controller,
+                                builder: (context, scrollController) {
+                                  return ListView.builder(
+                                    controller: scrollController,
+                                    itemCount: 100,
+                                    itemBuilder: (context, index) {
+                                      return ListTile(
+                                        title: Text('Item $index on Sheet 1'),
+                                      );
+                                    },
+                                  );
+                                },
+                              );
+                            });
+                          });
+                    },
+                    child: Text("Open Sheet 1")),
+                ElevatedButton(
+                    onPressed: () {
+                      showBottomSheet(
+                          context: context,
+                          builder: (context) {
+                            return DraggableScrollableSheet(
+                              controller: controller2,
+                              builder: (context, scrollController) {
+                                return ListView.builder(
+                                  controller: scrollController,
+                                  itemCount: 100,
+                                  itemBuilder: (context, index) {
+                                    return ListTile(
+                                      title: Text('Item $index on Sheet 2'),
+                                    );
+                                  },
+                                );
+                              },
+                            );
+                          });
+                    },
+                    child: Text("Open Sheet 2"))
+              ],
+            );
+          }),
+        ),
+      ));
+
+      // Open Sheet 1 and get the initial values
+      await tester.tap(find.text('Open Sheet 1'));
+      await tester.pumpAndSettle();
+      final controllerPixels = controller.pixels;
+      final controllerSize = controller.size;
+      final controllerIsAttached = controller.isAttached;
+      // Close Sheet 1 by dragging it down
+      await tester.fling(
+          find.byType(DraggableScrollableSheet), const Offset(0, 500), 300);
+      await tester.pumpAndSettle();
+
+      // Open Sheet 2 and get the initial values
+      await tester.tap(find.text('Open Sheet 2'));
+      await tester.pumpAndSettle();
+      final controller2Pixels = controller2.pixels;
+      final controller2Size = controller2.size;
+      final controller2IsAttached = controller2.isAttached;
+      // Close Sheet 2 by dragging it down
+      await tester.fling(
+          find.byType(DraggableScrollableSheet), const Offset(0, 500), 300);
+      await tester.pumpAndSettle();
+
+      // Compare the initial values of the two controllers
+      expect(controllerPixels, controller2Pixels);
+      expect(controllerSize, controller2Size);
+      expect(controllerIsAttached, controller2IsAttached);
+
+      // Open Sheet 1 again and use the controller to scroll
+      await tester.tap(find.text('Open Sheet 1'));
+      await tester.pumpAndSettle();
+      const targetSize = 1.0;
+      controller.jumpTo(targetSize);
+      expect(targetSize, controller.size);
+    });
+  });
+}