Reimplement core architecture (#106)

This PR has breaking changes. See `docs/migration-guide-0.5.x.md` for
more details.

The summary is:
- Moved responsibility for creating SheetExtent to SheetController
- Reimplemented SheetExtent as ValueListenable<SheetMetrics>
- Changed SheetActivity to directly update SheetExtent instead of having
its own `pixels`
- Refactored the core logic of NavigationSheet
- Bumped to 0.5.0

cookbook/lib/showcase/airbnb_mobile_app.dart

@@ -80,8 +80,8 @@ class _MapButton extends StatelessWidget {
     final sheetController = DefaultSheetController.of(context);
 
     void onPressed() {
-      final metrics = sheetController.metrics;
-      if (metrics != null) {
+      final metrics = sheetController.value;
+      if (metrics.hasDimensions) {
         // Collapse the sheet to reveal the map behind.
         sheetController.animateTo(
           Extent.pixels(metrics.minPixels),

cookbook/lib/tutorial/bottom_bar_visibility.dart

@@ -167,7 +167,7 @@ class _ExampleSheet extends StatelessWidget {
                   // The bottom bar is visible when at least 50% of the sheet is visible.
                   return metrics.pixels >=
                       const Extent.proportional(0.5)
-                          .resolve(metrics.contentDimensions);
+                          .resolve(metrics.contentSize);
                 },
                 child: bottomBar,
               ),

cookbook/lib/tutorial/sheet_content_scaffold.dart

@@ -45,10 +45,9 @@ class _ExampleSheet extends StatelessWidget {
       bottomBar: ConditionalStickyBottomBarVisibility(
         // This callback is called whenever the sheet's metrics changes.
         getIsVisible: (metrics) {
-          return metrics.viewportDimensions.insets.bottom == 0 &&
+          return metrics.viewportInsets.bottom == 0 &&
               metrics.pixels >
-                  const Extent.proportional(0.5)
-                      .resolve(metrics.contentDimensions);
+                  const Extent.proportional(0.5).resolve(metrics.contentSize);
         },
         child: buildBottomBar(),
       ),

cookbook/lib/tutorial/sheet_controller.dart

@@ -50,9 +50,9 @@ class _ExampleHomeState extends State<_ExampleHome> {
               // SheetController can be used to observe changes in the sheet extent.
               child: ValueListenableBuilder(
                 valueListenable: controller,
-                builder: (context, value, child) {
+                builder: (context, metrics, child) {
                   return Text(
-                    'Extent: ${value?.toStringAsFixed(1)}',
+                    'Extent: ${metrics.maybePixels?.toStringAsFixed(1)}',
                     style: Theme.of(context).textTheme.displaySmall,
                   );
                 },

docs/migration-guide-0.5.x.md

@@ -0,0 +1,96 @@
+# Migration guide to 0.5.x from 0.4.x
+
+The changes in v0.5.0 are summarized in the following list. The breaking changes are marked with :boom:.
+
+## Changes in SheetController
+
+- :boom: Now it implements `ValueListenable<SheetMetrics>` instead of `ValueListenable<double?>`.
+- Added `SheetStatus status`.
+- Added `createSheetExtent()`.
+
+## Changes in SheetNotification
+
+- Added `SheetStatus status`.
+
+## Changes in SheetMetrics
+
+- Added `double? maybePixels`.
+- Added `double? maybeMinPixels`.
+- Added `double? maybeMaxPixels`.
+- Added `Size? maybeContentSize`.
+- Added `Size? maybeViewportSize`.
+- Added `EdgeInsets? maybeViewportInsets`.
+- :boom: ​`pixels` is no longer nullable.
+
+- :boom: ​`minPixels` is no longer nullable.
+- :boom: ​`maxPixels` is no longer nullable.
+- :boom: ​`viewPixels` is no longer nullable.
+- :boom: ​`minViewPixels` is no longer nullable.
+- :boom: ​`maxViewPixels` is no longer nullable.
+- :boom: ​Changed `Size? contentDimensions` to `Size contentSize`.
+- Added `Size? viewportSize`.
+- Added `EdgeInsets? viewportInsets`.
+- :boom: ​Removed `ViewportDimensions viewportDimensions`.
+  - Use `viewportSize` and `viewportInsets` instead.
+- Added `double? maybeViewPixels`.
+- Added `double? maybeMinViewPixels`.
+- Added `double? maybeMaxViewPixels`.
+- :boom: ​Changed the signature of `copyWith()`.
+  - Renamed `contentDimensions` to `contentSize`.
+  - Removed `viewportDimensions`.
+  - Added `viewportSize` and `viewportInsets`.
+
+## Changes in SheetExtent
+
+- Now it implements `ValueListenable<SheetMetrics>`.
+- :boom: ​ `MaybeSheetMetrics` is no longer mixed in.
+
+- Added `SheetExtentConfig config`.
+- Added `SheetExtentDelegate delegate`.
+- Added `SheetMetrics metrics`.
+- Added `applyNewConfig()`.
+- Added `setPixels()`.
+- Added `correctPixels()`.
+- Added `SheetMetrics value`.
+- :boom: ​Removed `SheetMetricsSnapshot snapshot`
+- :boom: ​Removed `SheetPhysics physics`.
+  - Use `config.physics` instead.
+- :boom: ​Removed `Extent minExtent`.
+  - Use `config.minExtent` instead.
+- :boom: ​Removed `double? pixels`
+  - Use `metrics.pixels` instead.
+- :boom: ​Removed `double? minPixels`
+  - Use `metrics.minPixels` instead.
+- :boom: ​Removed `double? maxPixels`.
+  - Use `metrics.maxPixels` instead.
+- :boom: ​Renamed `applyNewContentDimensions()` to `applyNewContentSize()`.
+- :boom: ​Changed the signature of `applyNewDimensions()`.
+  - `void (ViewportDimensions)` → `void (Size, EdgeInsets)`
+
+### Added sub-components
+
+- `SheetExtentConfig`
+- `SheetExtentDelegate`
+
+### Removed sub-components
+
+- :boom: ​`MaybeSheetMetrics`
+  - Use `SheetMetrics.maybe*` instead to handle cases where values are null.
+- :boom: ​`ViewportDimensions`
+
+## Changes in SheetActivity
+
+- :boom: ​It is no longer a sub-class of `ChangeNotifier`.
+
+- :boom: ​Renamed `delegate` to `owner`.
+- :boom: ​Renamed `didChangeContentDimensions()` to `didChangeContentSize()`.
+
+- :boom: ​Removed `double? pixels`.
+- :boom: ​Removed `correctPixels()`.
+- :boom: ​Removed `setPixels()`.
+- :boom: ​Changed the signature of `didChangeViewportDimensions()`.
+  - `void (ViewportDimensions)` → `void (Size, EdgeInsets)`
+
+## Others
+
+- Added `kDefaultSheetPhysics`, which is the default `SheetPhysics` used by the sheet widgets.

package/CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 0.5.0 May 4, 2024
+
+This version contains some breaking changes. See the [migration guide](https://github.com/fujidaiti/smooth_sheets/blob/main/docs/migration-guide-0.5.x.md) for more details.
+
+- Attach default controller to sheet if not explicitly specified (#102)
+- Reimplement core architecture (#106)
+
 ## 0.4.2 Apr 21, 2024
 
 - Add new SheetNotifications for drag events (#92)

package/README.md

@@ -21,7 +21,9 @@ This library is currently in the experimental stage. The API may undergo changes
 
 ## Migration guide
 
-- [0.3.x to 0.4.x](https://github.com/fujidaiti/smooth_sheets/blob/main/docs/migration-guide-0.4.x.md) 🆕
+- [0.4.x to 0.5.x](https://github.com/fujidaiti/smooth_sheets/blob/main/docs/migration-guide-0.5.x.md) 🆕
+
+- [0.3.x to 0.4.x](https://github.com/fujidaiti/smooth_sheets/blob/main/docs/migration-guide-0.4.x.md)
 
 - [0.2.x to 0.3.x](https://github.com/fujidaiti/smooth_sheets/blob/main/docs/migration-guide-0.3.x.md)
 
@@ -313,7 +315,7 @@ A sheet dispatches a [SheetNotification](https://pub.dev/documentation/smooth_sh
 ```dart
 NotificationListener<SheetNotification>(
   onNotification: (notification) {
-    debugPrint('$notification');
+    debugPrint('${notification.metrics}');
     return false;
   },
   child: DraggableSheet(...),

package/lib/smooth_sheets.dart

@@ -18,7 +18,6 @@ export 'src/foundation/sheet_extent.dart';
 export 'src/foundation/theme.dart';
 export 'src/modal/cupertino.dart';
 export 'src/modal/modal_sheet.dart';
-export 'src/navigation/navigation_route.dart';
 export 'src/navigation/navigation_routes.dart';
 export 'src/navigation/navigation_sheet.dart';
 export 'src/scrollable/scrollable_sheet.dart'

package/lib/src/draggable/draggable_sheet.dart

@@ -42,16 +42,15 @@ class DraggableSheet extends StatelessWidget {
   /// The strategy to dismiss the on-screen keyboard when the sheet is dragged.
   final SheetKeyboardDismissBehavior? keyboardDismissBehavior;
 
-  /// {@macro SizedContentSheetExtent.initialExtent}
   final Extent initialExtent;
 
-  /// {@macro SheetExtent.minExtent}
+  /// {@macro SheetExtentConfig.minExtent}
   final Extent minExtent;
 
-  /// {@macro SheetExtent.maxExtent}
+  /// {@macro SheetExtentConfig.maxExtent}
   final Extent maxExtent;
 
-  /// {@macro SheetExtent.physics}
+  /// {@macro SheetExtentConfig.physics}
   final SheetPhysics? physics;
 
   /// An object that can be used to control and observe the sheet height.
@@ -68,6 +67,7 @@ class DraggableSheet extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = SheetTheme.maybeOf(context);
+    final physics = this.physics ?? theme?.physics ?? kDefaultSheetPhysics;
     final keyboardDismissBehavior =
         this.keyboardDismissBehavior ?? theme?.keyboardDismissBehavior;
 
@@ -76,11 +76,13 @@ class DraggableSheet extends StatelessWidget {
       builder: (context, controller) {
         return SheetContainer(
           controller: controller,
+          delegate: const DraggableSheetExtentDelegate(),
           config: DraggableSheetExtentConfig(
             initialExtent: initialExtent,
             minExtent: minExtent,
             maxExtent: maxExtent,
             physics: physics,
+            debugLabel: 'DraggableSheet',
           ),
           child: SheetDraggable(
             behavior: hitTestBehavior,
@@ -101,99 +103,48 @@ class DraggableSheet extends StatelessWidget {
   }
 }
 
-/// A configuration of a [DraggableSheetExtent].
-class DraggableSheetExtentConfig extends SheetExtentConfig {
-  const DraggableSheetExtentConfig({
-    required this.initialExtent,
-    required this.minExtent,
-    required this.maxExtent,
-    required this.physics,
-  });
-
-  /// {@macro DraggableSheetExtent.initialExtent}
-  final Extent initialExtent;
-
-  /// {@macro SheetExtent.minExtent}
-  final Extent minExtent;
-
-  /// {@macro SheetExtent.maxExtent}
-  final Extent maxExtent;
-
-  /// {@macro SheetExtent.physics}
-  final SheetPhysics? physics;
-
-  @override
-  bool shouldRebuild(BuildContext context, SheetExtent oldExtent) {
-    return oldExtent is! DraggableSheetExtent ||
-        oldExtent.minExtent != minExtent ||
-        oldExtent.maxExtent != maxExtent ||
-        oldExtent.initialExtent != initialExtent ||
-        oldExtent.physics != _resolvePhysics(context);
-  }
+class DraggableSheetExtentDelegate with SheetExtentDelegate {
+  const DraggableSheetExtentDelegate();
 
   @override
-  SheetExtent build(BuildContext context, SheetContext sheetContext) {
-    return DraggableSheetExtent(
-      context: sheetContext,
-      initialExtent: initialExtent,
-      minExtent: minExtent,
-      maxExtent: maxExtent,
-      physics: _resolvePhysics(context),
-    );
-  }
-
-  SheetPhysics _resolvePhysics(BuildContext context) {
-    const fallback = StretchingSheetPhysics(parent: SnappingSheetPhysics());
-    final theme = SheetTheme.maybeOf(context);
-    final base = theme?.basePhysics;
-    if (physics case final physics?) {
-      return base != null ? physics.applyTo(base) : physics;
-    } else if (theme?.physics case final inherited?) {
-      // Do not apply the base physics to the inherited physics.
-      return inherited;
-    } else {
-      return base != null ? fallback.applyTo(base) : fallback;
-    }
+  SheetActivity createIdleActivity() {
+    return _IdleDraggableSheetActivity();
   }
 }
 
-/// [SheetExtent] for a [DraggableSheet].
-class DraggableSheetExtent extends SheetExtent {
-  DraggableSheetExtent({
-    required super.context,
-    required super.physics,
+class DraggableSheetExtentConfig extends SheetExtentConfig {
+  const DraggableSheetExtentConfig({
+    required this.initialExtent,
     required super.minExtent,
     required super.maxExtent,
-    required this.initialExtent,
-  }) {
-    goIdle();
-  }
+    required super.physics,
+    super.debugLabel,
+  });
 
-  /// {@template DraggableSheetExtent.initialExtent}
-  /// The initial extent of the sheet when it is first shown.
-  /// {@endtemplate}
   final Extent initialExtent;
 
   @override
-  void goIdle() {
-    beginActivity(_IdleDraggableSheetActivity(
-      initialExtent: initialExtent,
-    ));
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    return other is DraggableSheetExtentConfig &&
+        other.initialExtent == initialExtent &&
+        super == other;
   }
+
+  @override
+  int get hashCode => Object.hash(initialExtent, super.hashCode);
 }
 
 class _IdleDraggableSheetActivity extends IdleSheetActivity {
-  _IdleDraggableSheetActivity({
-    required this.initialExtent,
-  });
-
-  final Extent initialExtent;
+  _IdleDraggableSheetActivity();
 
   @override
-  void didChangeContentDimensions(Size? oldDimensions) {
-    super.didChangeContentDimensions(oldDimensions);
-    if (pixels == null) {
-      setPixels(initialExtent.resolve(delegate.contentDimensions!));
+  void didChangeContentSize(Size? oldDimensions) {
+    super.didChangeContentSize(oldDimensions);
+    final config = owner.config;
+    final metrics = owner.metrics;
+    if (metrics.maybePixels == null && config is DraggableSheetExtentConfig) {
+      owner.setPixels(config.initialExtent.resolve(metrics.contentSize));
     }
   }
 }