feat: add Hook for managing SnapshotController instances

Author: benthillerkus

packages/flutter_hooks/lib/src/hooks.dart

@@ -41,3 +41,4 @@ part 'transformation_controller.dart';
 part 'tree_sliver_controller.dart';
 part 'widget_states_controller.dart';
 part 'widgets_binding_observer.dart';
+part 'snapshot_controller.dart';

packages/flutter_hooks/lib/src/snapshot_controller.dart

@@ -0,0 +1,61 @@
+part of 'hooks.dart';
+
+/// Creates and disposes a [SnapshotController].
+/// 
+/// Note that [allowSnapshotting] must be set to `true`
+/// in order for this controller to actually do anything.
+/// This is consistent with [SnapshotController.new].
+/// 
+/// If [allowSnapshotting] changes on subsequent calls to [useSnapshotController],
+/// [SnapshotController.allowSnapshotting] will be called to update accordingly.
+/// 
+/// ```dart
+/// final controller = useSnapshotController(allowSnapshotting: true);
+/// // is equivalent to
+/// final controller = useSnapshotController();
+/// controller.allowSnapshotting = true;
+/// ```
+///
+/// See also:
+/// - [SnapshotController]
+SnapshotController useSnapshotController({
+  bool allowSnapshotting = false,
+}) {
+  return use(
+    _SnapshotControllerHook(
+      allowSnapshotting: allowSnapshotting,
+    ),
+  );
+}
+
+class _SnapshotControllerHook extends Hook<SnapshotController> {
+  const _SnapshotControllerHook({
+    required this.allowSnapshotting,
+  });
+
+  final bool allowSnapshotting;
+
+  @override
+  HookState<SnapshotController, Hook<SnapshotController>>
+      createState() => _SnapshotControllerHookState();
+}
+
+class _SnapshotControllerHookState
+    extends HookState<SnapshotController, _SnapshotControllerHook> {
+  late final controller = SnapshotController(allowSnapshotting: hook.allowSnapshotting);
+
+  @override
+  void didUpdateHook(_SnapshotControllerHook oldHook) {
+    super.didUpdateHook(oldHook);
+    controller.allowSnapshotting = hook.allowSnapshotting;
+  }
+
+  @override
+  SnapshotController build(BuildContext context) => controller;
+
+  @override
+  void dispose() => controller.dispose();
+
+  @override
+  String get debugLabel => 'useSnapshotController';
+}

packages/flutter_hooks/test/use_snapshot_controller_test.dart

@@ -0,0 +1,75 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.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) {
+        useSnapshotController();
+        return const SizedBox();
+      }),
+    );
+
+    await tester.pump();
+
+    final element = tester.element(find.byType(HookBuilder));
+
+    expect(
+      element
+          .toDiagnosticsNode(style: DiagnosticsTreeStyle.offstage)
+          .toStringDeep(),
+      equalsIgnoringHashCodes(
+        'HookBuilder\n'
+        " │ useSnapshotController: Instance of 'SnapshotController'\n"
+        ' └SizedBox(renderObject: RenderConstrainedBox#00000)\n',
+      ),
+    );
+  });
+
+  group('useSnapshotController', () {
+    testWidgets('initial values matches with real constructor', (tester) async {
+      late SnapshotController controller;
+      late SnapshotController controller2;
+
+      await tester.pumpWidget(
+        HookBuilder(builder: (context) {
+          controller2 = SnapshotController();
+          controller = useSnapshotController();
+          return Container();
+        }),
+      );
+
+      expect(controller.allowSnapshotting, controller2.allowSnapshotting);
+    });
+
+    testWidgets('passes hook parameters to the SnapshotController',
+        (tester) async {
+      late SnapshotController controller;
+
+      await tester.pumpWidget(
+        HookBuilder(builder: (context) {
+          controller = useSnapshotController(allowSnapshotting: true);
+          return const SizedBox();
+        }),
+      );
+
+      expect(controller.allowSnapshotting, true);
+
+      late SnapshotController retrievedController;
+      await tester.pumpWidget(
+        HookBuilder(builder: (context) {
+          // ignore: avoid_redundant_argument_values
+          retrievedController = useSnapshotController(allowSnapshotting: false);
+          return const SizedBox();
+        }),
+      );
+
+      expect(retrievedController, same(controller));
+      expect(retrievedController.allowSnapshotting, false);
+    });
+  });
+}