Switch to new Flutter 3.24.0 Navigator API: onDidRemovePage

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.0.2
+
+* Switch to new Flutter 3.24.0 Navigator API: `onDidRemovePage`
+  * Make use of `Page.canPop` and `Page.onPopInvoke` to tell the framework which pages can be popped.  
+    This can be configured / changed during the page's display, e.g. to prevent back swipes once a form contains changes.
+
 ## 0.0.1
 
-* TODO: Describe initial release.
+* Initial release with basic page and navigtable source ("bloc for routing") support

example/ios/Runner/AppDelegate.swift

@@ -1,7 +1,7 @@
 import Flutter
 import UIKit
 
-@UIApplicationMain
+@main
 @objc class AppDelegate: FlutterAppDelegate {
   override func application(
     _ application: UIApplication,

example/lib/main.dart

@@ -51,6 +51,7 @@ class ExampleSelectionNavigator
       ExampleSelectionPage(
         examples: {
           'List Detail': () => ListDetailNavigator(),
+          'Dynamic back behavior': () => DynamicPopNavigator(),
         },
         // TODO(tp): Dispose previous if needed
         onExampleSelect: (exampleFactory) {
@@ -62,7 +63,7 @@ class ExampleSelectionNavigator
 
           this.state = exampleFactory();
         },
-      ).page,
+      ).page(onPop: null),
       if (state != null)
         if (state is NavigatableSource)
           // Use pipe type trick for type preservation? (not extension, but rather on class)
@@ -127,6 +128,89 @@ class ExampleSelectionPage extends StatelessWidget {
   }
 }
 
+class DynamicPopNavigator extends MappedNavigatableSource<
+    (
+      bool /* shows child */,
+      bool /* can pop */,
+    )> {
+  DynamicPopNavigator() : super(initialState: (true, false));
+
+  @override
+  List<DeclarativeNavigatable> build((bool, bool) state) {
+    final canPop = state.$2;
+
+    return [
+      const Placeholder().page(onPop: null),
+      if (state.$1)
+        PopToggle(
+          value: canPop,
+          onChange: (v) => this.state = (true, v),
+        ).page(onPop: canPop ? () => this.state = (false, false) : null),
+    ];
+  }
+}
+
+class PopToggle extends StatelessWidget {
+  const PopToggle({
+    super.key,
+    required this.value,
+    required this.onChange,
+  });
+
+  final bool value;
+
+  final ValueSetter<bool> onChange;
+
+  @override
+  Widget build(BuildContext context) {
+    if (Theme.of(context).platform == TargetPlatform.android) {
+      return Scaffold(
+        appBar: AppBar(
+          title: const Text('Dynamic pop'),
+        ),
+        body: Switch(
+          value: value,
+          onChanged: onChange,
+        ),
+      );
+    }
+
+    return CupertinoPageScaffold(
+      navigationBar: const CupertinoNavigationBar(
+        middle: Text('Dynamic Pop'),
+      ),
+      child: Container(
+        color: CupertinoColors.systemGroupedBackground,
+        child: SafeArea(
+          child: Column(
+            children: [
+              Expanded(
+                child: SingleChildScrollView(
+                  physics: const AlwaysScrollableScrollPhysics(),
+                  child: Padding(
+                    padding: const EdgeInsets.symmetric(vertical: 20.0),
+                    child: CupertinoFormSection.insetGrouped(
+                      children: [
+                        CupertinoListTile.notched(
+                          trailing: CupertinoSwitch(
+                            value: value,
+                            onChanged: onChange,
+                          ),
+                          title: const Text('Can pop'),
+                        ),
+                      ],
+                    ),
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
 class ListDetailNavigator extends MappedNavigatableSource<int?> {
   ListDetailNavigator() : super(initialState: null);
 
@@ -135,14 +219,14 @@ class ListDetailNavigator extends MappedNavigatableSource<int?> {
     return [
       NumberSelectionPage(
         onNumberSelect: (number) => this.state = number,
-      ).page,
+      ).page(onPop: null),
       if (state != null)
         if (state == 7)
           LuckyNumberSevenPage(
             onTap: () => this.state = null,
-          ).popup
+          ).popup(onPop: () => this.state = null)
         else
-          NumberDetailPage(number: state).page..onPop = () => this.state = null,
+          NumberDetailPage(number: state).page(onPop: () => this.state = null),
     ];
   }
 }

example/pubspec.lock

@@ -63,7 +63,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.0.1"
+    version: "0.0.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -86,18 +86,18 @@ packages:
     dependency: transitive
     description:
       name: leak_tracker
-      sha256: "7f0df31977cb2c0b88585095d168e689669a2cc9b97c309665e3386f3e9d341a"
+      sha256: "3f87a60e8c63aecc975dda1ceedbc8f24de75f09e4856ea27daf8958f2f0ce05"
       url: "https://pub.dev"
     source: hosted
-    version: "10.0.4"
+    version: "10.0.5"
   leak_tracker_flutter_testing:
     dependency: transitive
     description:
       name: leak_tracker_flutter_testing
-      sha256: "06e98f569d004c1315b991ded39924b21af84cf14cc94791b8aea337d25b57f8"
+      sha256: "932549fb305594d82d7183ecd9fa93463e9914e1b67cacc34bc40906594a1806"
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.3"
+    version: "3.0.5"
   leak_tracker_testing:
     dependency: transitive
     description:
@@ -126,18 +126,18 @@ packages:
     dependency: transitive
     description:
       name: material_color_utilities
-      sha256: "0e0a020085b65b6083975e499759762399b4475f766c21668c4ecca34ea74e5a"
+      sha256: f7142bb1154231d7ea5f96bc7bde4bda2a0945d2806bb11670e30b850d56bdec
       url: "https://pub.dev"
     source: hosted
-    version: "0.8.0"
+    version: "0.11.1"
   meta:
     dependency: transitive
     description:
       name: meta
-      sha256: "7687075e408b093f36e6bbf6c91878cc0d4cd10f409506f7bc996f68220b9136"
+      sha256: bdb68674043280c3428e9ec998512fb681678676b3c54e773629ffe74419f8c7
       url: "https://pub.dev"
     source: hosted
-    version: "1.12.0"
+    version: "1.15.0"
   path:
     dependency: transitive
     description:
@@ -195,10 +195,10 @@ packages:
     dependency: transitive
     description:
       name: test_api
-      sha256: "9955ae474176f7ac8ee4e989dadfb411a58c30415bcfb648fa04b2b8a03afa7f"
+      sha256: "5b8a98dafc4d5c4c9c72d8b31ab2b23fc13422348d2997120294d3bac86b4ddb"
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.0"
+    version: "0.7.2"
   vector_math:
     dependency: transitive
     description:
@@ -211,10 +211,10 @@ packages:
     dependency: transitive
     description:
       name: vm_service
-      sha256: "3923c89304b715fb1eb6423f017651664a03bf5f4b29983627c4da791f74a4ec"
+      sha256: f652077d0bdf60abe4c1f6377448e8655008eef28f128bc023f7b5e8dfeb48fc
       url: "https://pub.dev"
     source: hosted
-    version: "14.2.1"
+    version: "14.2.4"
 sdks:
   dart: ">=3.4.4 <4.0.0"
-  flutter: ">=3.18.0-18.0.pre.54"
+  flutter: ">=3.24.0"

example/test/widget_test.dart

@@ -2,19 +2,6 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   testWidgets('TODO', (WidgetTester tester) async {
-    // // Build our app and trigger a frame.
-    // await tester.pumpWidget(const MyApp());
-
-    // // Verify that our counter starts at 0.
-    // expect(find.text('0'), findsOneWidget);
-    // expect(find.text('1'), findsNothing);
-
-    // // Tap the '+' icon and trigger a frame.
-    // await tester.tap(find.byIcon(Icons.add));
-    // await tester.pump();
-
-    // // Verify that our counter has incremented.
-    // expect(find.text('0'), findsNothing);
-    // expect(find.text('1'), findsOneWidget);
+    // TODO(tp): Move goldens in here so implementation can be shared with demo gallery?
   });
 }

lib/fdr.dart

@@ -2,3 +2,4 @@
 library fdr;
 
 export './src/declarative_navigator.dart';
+export './src/pages/fdr_page.dart';

lib/src/declarative_navigator.dart

@@ -1,5 +1,7 @@
 // ignore_for_file: unused_element
 
+import 'package:fdr/src/pages/cupertino_page.dart';
+import 'package:fdr/src/pages/material_page.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
@@ -69,17 +71,8 @@ class _DeclarativeNavigatorState extends State<DeclarativeNavigator> {
 
     return Navigator(
       pages: pageNavigatables.map((n) => n.page).toList(),
-      onPopPage: (route, result) {
-        debugPrint('onPopPage: $route $result');
-
-        if (pageNavigatables.last.onPop != null) {
-          pageNavigatables.last.onPop!();
-
-          // pop will not yet be completed on edge-swipe (as the animation still runs), so we can not yet return `true`
-          return false;
-        }
-
-        return false;
+      onDidRemovePage: (page) {
+        debugPrint('onPopPage: $page');
       },
     );
   }
@@ -130,16 +123,20 @@ class __ManagingDeclarativeNavigatorState
 
 sealed class DeclarativeNavigatable {}
 
+typedef PageBuilder = Page Function(VoidCallback? onPop);
+
 class DeclarativeNavigatablePage implements DeclarativeNavigatable {
   DeclarativeNavigatablePage({
-    required this.page,
-    this.onPop,
-  });
+    required PageBuilder builder,
+    required this.onPop,
+  })  : _builder = builder,
+        page = builder(onPop);
+
+  final PageBuilder _builder;
 
   final Page page;
 
-  // TODO(tp): Make final, and then provide better creators
-  VoidCallback? onPop;
+  final VoidCallback? onPop;
 }
 
 extension Poppable on NavigatableSource {
@@ -170,7 +167,7 @@ class _PoppableNavigatableSourceWrapper implements NavigatableSource {
 
     _pages.value = [
       DeclarativeNavigatablePage(
-        page: pages.first.page,
+        builder: pages.first._builder,
         // TODO(tp): What about the underlying onpop, if any? (though unlikely makes sense)
         onPop: onPop,
       ),
@@ -184,19 +181,47 @@ class _PoppableNavigatableSourceWrapper implements NavigatableSource {
   }
 }
 
-extension DeclarativeNavigatableFromPage on Page {
-  DeclarativeNavigatablePage get navigatable {
-    return DeclarativeNavigatablePage(page: this);
-  }
-}
-
 extension DeclarativeNavigatableFromWidget on Widget {
-  DeclarativeNavigatablePage get page {
-    return CupertinoPage(child: this).navigatable;
+  DeclarativeNavigatablePage page({
+    /// Provide `null` if the page should not be poppable
+    required VoidCallback? onPop,
+  }) {
+    return DeclarativeNavigatablePage(
+      builder: (onPop) => defaultTargetPlatform == TargetPlatform.android
+          ? FDRMaterialPage(
+              child: this,
+              canPop: onPop != null,
+              onPopInvoked: (didPop, _) {
+                if (didPop) {
+                  // When the route was popped, it had to be pop-able (`canPop = true`),
+                  // such that there is a callback to update the state to reflect its absence
+                  onPop!();
+                }
+              },
+            )
+          : FDRCupertinoPage(
+              child: this,
+              canPop: onPop != null,
+              onPopInvoked: (didPop, _) {
+                if (didPop) {
+                  // When the route was popped, it had to be pop-able (`canPop = true`),
+                  // such that there is a callback to update the state to reflect its absence
+                  onPop!();
+                }
+              },
+            ),
+      onPop: onPop,
+    );
   }
 
-  DeclarativeNavigatablePage get popup {
-    return _CupertinoModalPopupPage(child: this).navigatable;
+  DeclarativeNavigatablePage popup({
+    /// Provide `null` if the model should not be poppable
+    required VoidCallback? onPop,
+  }) {
+    return DeclarativeNavigatablePage(
+      builder: (onPop) => _CupertinoModalPopupPage(child: this),
+      onPop: onPop,
+    );
   }
 }
 
@@ -208,6 +233,7 @@ class _CupertinoModalPopupPage extends Page {
     super.restorationId,
     required this.child,
   });
+
   final Widget child;
 
   @override