Add delegate route logic

flutter · MitchellGoodwin · Feb 15, 2024 · Feb 16, 2024 · Feb 20, 2024 · Mar 6, 2024
commit 00b7dda007eee4912575a6fa9bd30e6fb9677583
diff --git a/packages/flutter/lib/src/cupertino/route.dart b/packages/flutter/lib/src/cupertino/route.dart
@@ -153,7 +153,7 @@ mixin CupertinoRouteTransitionMixin<T> on PageRoute<T> {
   @override
   bool canTransitionTo(TransitionRoute<dynamic> nextRoute) {
     // Don't perform outgoing animation if the next route is a fullscreen dialog.
-    return nextRoute is CupertinoRouteTransitionMixin && !nextRoute.fullscreenDialog;
+    return !(nextRoute is CupertinoRouteTransitionMixin && nextRoute.fullscreenDialog);
   }
 
   @override
@@ -487,10 +487,17 @@ class _CupertinoPageTransitionState extends State<CupertinoPageTransition> {
   Widget build(BuildContext context) {
     assert(debugCheckHasDirectionality(context));
     final TextDirection textDirection = Directionality.of(context);
-    return SlideTransition(
-      position: _secondaryPositionAnimation,
-      textDirection: textDirection,
-      transformHitTests: false,
+    return DelegatedTransition(
+      context: context,
+      animation: widget.secondaryRouteAnimation,
+      builder: (BuildContext context, Widget? child) {
+        return SlideTransition(
+          position: _secondaryPositionAnimation,
+          textDirection: textDirection,
+          transformHitTests: false,
+          child: child,
+        );
+      },
       child: SlideTransition(
         position: _primaryPositionAnimation,
         textDirection: textDirection,

diff --git a/packages/flutter/lib/src/material/page_transitions_theme.dart b/packages/flutter/lib/src/material/page_transitions_theme.dart
@@ -77,6 +77,38 @@ class _OpenUpwardsPageTransition extends StatefulWidget {
   // Used by all of the transition animations.
   static const Curve _transitionCurve = Cubic(0.20, 0.00, 0.00, 1.00);
 
+  static Widget delegateTransition(BuildContext context, Widget? child, Animation<double> secondaryAnimation) {
+    final Animation<Offset> secondaryTranslationAnimation = _secondaryTranslationTween.animate(
+      CurvedAnimation(
+        parent: secondaryAnimation,
+        curve: _transitionCurve,
+        reverseCurve: _transitionCurve.flipped,
+      ),
+    );
+
+    final CurvedAnimation primaryAnimation = CurvedAnimation(
+      parent: ReverseAnimation(secondaryAnimation),
+      curve: _transitionCurve,
+      reverseCurve: _transitionCurve.flipped,
+    );
+
+    final Animation<Offset> primaryTranslationAnimation = _primaryTranslationTween.animate(primaryAnimation);
+
+    return AnimatedBuilder(
+      animation: secondaryAnimation,
+      child: FractionalTranslation(
+        translation: secondaryTranslationAnimation.value,
+        child: child,
+      ),
+      builder: (BuildContext context, Widget? child) {
+        return FractionalTranslation(
+          translation: secondaryTranslationAnimation.value,
+          child: child,
+        );
+      },
+    );
+  }
+
   final Animation<double> animation;
   final Animation<double> secondaryAnimation;
   final Widget child;
@@ -290,28 +322,35 @@ class _ZoomPageTransition extends StatelessWidget {
           child: child,
         );
       },
-      child: DualTransitionBuilder(
-        animation: ReverseAnimation(secondaryAnimation),
-        forwardBuilder: (
-          BuildContext context,
-          Animation<double> animation,
-          Widget? child,
-        ) {
-          return _ZoomEnterTransition(
-            animation: animation,
-            allowSnapshotting: allowSnapshotting && allowEnterRouteSnapshotting ,
-            reverse: true,
-            child: child,
-          );
-        },
-        reverseBuilder: (
-          BuildContext context,
-          Animation<double> animation,
-          Widget? child,
-        ) {
-          return _ZoomExitTransition(
-            animation: animation,
-            allowSnapshotting: allowSnapshotting,
+      child: DelegatedTransition(
+        context: context,
+        animation: secondaryAnimation,
+        builder: (BuildContext context, Widget? child) {
+          return DualTransitionBuilder(
+            animation: ReverseAnimation(secondaryAnimation),
+            forwardBuilder: (
+              BuildContext context,
+              Animation<double> animation,
+              Widget? child,
+            ) {
+              return _ZoomEnterTransition(
+                animation: animation,
+                allowSnapshotting: allowSnapshotting && allowEnterRouteSnapshotting ,
+                reverse: true,
+                child: child,
+              );
+            },
+            reverseBuilder: (
+              BuildContext context,
+              Animation<double> animation,
+              Widget? child,
+            ) {
+              return _ZoomExitTransition(
+                animation: animation,
+                allowSnapshotting: allowSnapshotting,
+                child: child,
+              );
+            },
             child: child,
           );
         },
@@ -624,6 +663,11 @@ class OpenUpwardsPageTransitionsBuilder extends PageTransitionsBuilder {
   /// Android P.
   const OpenUpwardsPageTransitionsBuilder();
 
+  /// Delegate animation
+  static Widget delegateTransition(BuildContext context, Widget? child, Animation<double> secondaryAnimation) {
+    return _OpenUpwardsPageTransition.delegateTransition(context, child, secondaryAnimation);
+  }
+
   @override
   Widget buildTransitions<T>(
     PageRoute<T>? route,
@@ -702,6 +746,37 @@ class ZoomPageTransitionsBuilder extends PageTransitionsBuilder {
   // for the Impeller backend.
   static const bool _kProfileForceDisableSnapshotting = bool.fromEnvironment('flutter.benchmarks.force_disable_snapshot');
 
+  /// The delegated transition.
+  static Widget delegateTransition(BuildContext context, Widget? child, Animation<double> secondaryAnimation) {
+    return DualTransitionBuilder(
+      animation: ReverseAnimation(secondaryAnimation),
+      forwardBuilder: (
+        BuildContext context,
+        Animation<double> animation,
+        Widget? child,
+      ) {
+        return _ZoomEnterTransition(
+          animation: animation,
+          allowSnapshotting: true ,
+          reverse: true,
+          child: child,
+        );
+      },
+      reverseBuilder: (
+        BuildContext context,
+        Animation<double> animation,
+        Widget? child,
+      ) {
+        return _ZoomExitTransition(
+          animation: animation,
+          allowSnapshotting: true,
+          child: child,
+        );
+      },
+      child: child,
+    );
+  }
+
   @override
   Widget buildTransitions<T>(
     PageRoute<T> route,

diff --git a/packages/flutter/lib/src/widgets/navigator.dart b/packages/flutter/lib/src/widgets/navigator.dart
@@ -4847,8 +4847,9 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
   ///  * [restorablePush], which pushes a route that can be restored during
   ///    state restoration.
   @optionalTypeArgs
-  Future<T?> push<T extends Object?>(Route<T> route) {
+  Future<T?> push<T extends Object?>(Route<T> route, [Widget Function(BuildContext context, Widget? child, Animation<double> animation)? delegateBuilder]) {
     _pushEntry(_RouteEntry(route, pageBased: false, initialState: _RouteLifecycle.push));
+    delegateTransitionBuilder = delegateBuilder;
     return route.popped;
   }
 
@@ -5516,6 +5517,15 @@ class NavigatorState extends State<Navigator> with TickerProviderStateMixin, Res
   /// Notifies its listeners if the value of [userGestureInProgress] changes.
   final ValueNotifier<bool> userGestureInProgressNotifier = ValueNotifier<bool>(false);
 
+  /// Notifies its listeners if there is a delegate transition from the top route.
+  final ValueNotifier<Widget Function(BuildContext context, Widget? child, Animation<double> animation)?> delegateTransitionBuilderNotifier = ValueNotifier<Widget Function(BuildContext context, Widget? child, Animation<double> animation)?>(null);
+
+  /// Sets the delegate transition.
+  set delegateTransitionBuilder(Widget Function(BuildContext context, Widget? child, Animation<double> animation)? builder) => delegateTransitionBuilderNotifier.value = builder;
+
+  /// Gets the delegate transition.
+  Widget Function(BuildContext context, Widget? child, Animation<double> animation)? get delegateTransitionBuilder => delegateTransitionBuilderNotifier.value;
+
   /// The navigator is being controlled by a user gesture.
   ///
   /// For example, called when the user beings an iOS back gesture.

diff --git a/packages/flutter/lib/src/widgets/transitions.dart b/packages/flutter/lib/src/widgets/transitions.dart
@@ -9,6 +9,7 @@ import 'package:flutter/rendering.dart';
 import 'basic.dart';
 import 'container.dart';
 import 'framework.dart';
+import 'navigator.dart';
 import 'text.dart';
 
 export 'package:flutter/rendering.dart' show RelativeRect;
@@ -138,6 +139,32 @@ class _AnimatedState extends State<AnimatedWidget> {
   Widget build(BuildContext context) => widget.build(context);
 }
 
+/// Delegates to transition from navigator if available, or returns default.
+class DelegatedTransition extends AnimatedBuilder {
+
+  /// Creates a DelegatedTransiton
+  const DelegatedTransition({
+    super.key,
+    super.child,
+    required super.animation,
+    required super.builder,
+    required this.context,
+  });
+
+  /// context
+  final BuildContext context;
+
+  @override
+  Widget build(BuildContext context) {
+    final NavigatorState navigatorState = Navigator.of(context);
+    final Widget Function(BuildContext context, Widget? child, Animation<double> animation)? delegateTransitionBuilder = navigatorState.delegateTransitionBuilder;
+    if (delegateTransitionBuilder == null) {
+      return builder(context, child);
+    }
+    return delegateTransitionBuilder(context, child, animation as Animation<double>);
+  }
+}
+
 /// Animates the position of a widget relative to its normal position.
 ///
 /// The translation is expressed as an [Offset] scaled to the child's size. For