// Copyright 2014 The Flutter Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. import 'package:flutter/cupertino.dart'; import 'package:flutter/foundation.dart'; import 'colors.dart'; import 'theme.dart'; // Slides the page upwards and fades it in, starting from 1/4 screen // below the top. The transition is intended to match the default for // Android O. class _FadeUpwardsPageTransition extends StatelessWidget { _FadeUpwardsPageTransition({ required Animation<double> routeAnimation, // The route's linear 0.0 - 1.0 animation. required this.child, }) : _positionAnimation = routeAnimation.drive(_bottomUpTween.chain(_fastOutSlowInTween)), _opacityAnimation = routeAnimation.drive(_easeInTween); // Fractional offset from 1/4 screen below the top to fully on screen. static final Tween<Offset> _bottomUpTween = Tween<Offset>( begin: const Offset(0.0, 0.25), end: Offset.zero, ); static final Animatable<double> _fastOutSlowInTween = CurveTween(curve: Curves.fastOutSlowIn); static final Animatable<double> _easeInTween = CurveTween(curve: Curves.easeIn); final Animation<Offset> _positionAnimation; final Animation<double> _opacityAnimation; final Widget child; @override Widget build(BuildContext context) { return SlideTransition( position: _positionAnimation, // TODO(ianh): tell the transform to be un-transformed for hit testing child: FadeTransition( opacity: _opacityAnimation, child: child, ), ); } } // This transition is intended to match the default for Android P. class _OpenUpwardsPageTransition extends StatelessWidget { const _OpenUpwardsPageTransition({ required this.animation, required this.secondaryAnimation, required this.child, }); // The new page slides upwards just a little as its clip // rectangle exposes the page from bottom to top. static final Tween<Offset> _primaryTranslationTween = Tween<Offset>( begin: const Offset(0.0, 0.05), end: Offset.zero, ); // The old page slides upwards a little as the new page appears. static final Tween<Offset> _secondaryTranslationTween = Tween<Offset>( begin: Offset.zero, end: const Offset(0.0, -0.025), ); // The scrim obscures the old page by becoming increasingly opaque. static final Tween<double> _scrimOpacityTween = Tween<double>( begin: 0.0, end: 0.25, ); // Used by all of the transition animations. static const Curve _transitionCurve = Cubic(0.20, 0.00, 0.00, 1.00); final Animation<double> animation; final Animation<double> secondaryAnimation; final Widget child; @override Widget build(BuildContext context) { return LayoutBuilder( builder: (BuildContext context, BoxConstraints constraints) { final Size size = constraints.biggest; final CurvedAnimation primaryAnimation = CurvedAnimation( parent: animation, curve: _transitionCurve, reverseCurve: _transitionCurve.flipped, ); // Gradually expose the new page from bottom to top. final Animation<double> clipAnimation = Tween<double>( begin: 0.0, end: size.height, ).animate(primaryAnimation); final Animation<double> opacityAnimation = _scrimOpacityTween.animate(primaryAnimation); final Animation<Offset> primaryTranslationAnimation = _primaryTranslationTween.animate(primaryAnimation); final Animation<Offset> secondaryTranslationAnimation = _secondaryTranslationTween.animate( CurvedAnimation( parent: secondaryAnimation, curve: _transitionCurve, reverseCurve: _transitionCurve.flipped, ), ); return AnimatedBuilder( animation: animation, builder: (BuildContext context, Widget? child) { return Container( color: Colors.black.withOpacity(opacityAnimation.value), alignment: Alignment.bottomLeft, child: ClipRect( child: SizedBox( height: clipAnimation.value, child: OverflowBox( alignment: Alignment.bottomLeft, maxHeight: size.height, child: child, ), ), ), ); }, child: AnimatedBuilder( animation: secondaryAnimation, child: FractionalTranslation( translation: primaryTranslationAnimation.value, child: child, ), builder: (BuildContext context, Widget? child) { return FractionalTranslation( translation: secondaryTranslationAnimation.value, child: child, ); }, ), ); }, ); } } // Zooms and fades a new page in, zooming out the previous page. This transition // is designed to match the Android Q activity transition. class _ZoomPageTransition extends StatelessWidget { /// Creates a [_ZoomPageTransition]. /// /// The [animation] and [secondaryAnimation] argument are required and must /// not be null. const _ZoomPageTransition({ required this.animation, required this.secondaryAnimation, this.child, }) : assert(animation != null), assert(secondaryAnimation != null); // A curve sequence that is similar to the 'fastOutExtraSlowIn' curve used in // the native transition. static final List<TweenSequenceItem<double>> fastOutExtraSlowInTweenSequenceItems = <TweenSequenceItem<double>>[ TweenSequenceItem<double>( tween: Tween<double>(begin: 0.0, end: 0.4) .chain(CurveTween(curve: const Cubic(0.05, 0.0, 0.133333, 0.06))), weight: 0.166666, ), TweenSequenceItem<double>( tween: Tween<double>(begin: 0.4, end: 1.0) .chain(CurveTween(curve: const Cubic(0.208333, 0.82, 0.25, 1.0))), weight: 1.0 - 0.166666, ), ]; static final TweenSequence<double> _scaleCurveSequence = TweenSequence<double>(fastOutExtraSlowInTweenSequenceItems); /// The animation that drives the [child]'s entrance and exit. /// /// See also: /// /// * [TransitionRoute.animation], which is the value given to this property /// when the [_ZoomPageTransition] is used as a page transition. final Animation<double> animation; /// The animation that transitions [child] when new content is pushed on top /// of it. /// /// See also: /// /// * [TransitionRoute.secondaryAnimation], which is the value given to this /// property when the [_ZoomPageTransition] is used as a page transition. final Animation<double> secondaryAnimation; /// The widget below this widget in the tree. /// /// This widget will transition in and out as driven by [animation] and /// [secondaryAnimation]. final Widget? child; @override Widget build(BuildContext context) { return DualTransitionBuilder( animation: animation, forwardBuilder: ( BuildContext context, Animation<double> animation, Widget? child, ) { return _ZoomEnterTransition( animation: animation, child: child, ); }, reverseBuilder: ( BuildContext context, Animation<double> animation, Widget? child, ) { return _ZoomExitTransition( animation: animation, reverse: true, child: child, ); }, child: DualTransitionBuilder( animation: ReverseAnimation(secondaryAnimation), forwardBuilder: ( BuildContext context, Animation<double> animation, Widget? child, ) { return _ZoomEnterTransition( animation: animation, reverse: true, child: child, ); }, reverseBuilder: ( BuildContext context, Animation<double> animation, Widget? child, ) { return _ZoomExitTransition( animation: animation, child: child, ); }, child: child, ), ); } } class _ZoomEnterTransition extends StatelessWidget { const _ZoomEnterTransition({ required this.animation, this.reverse = false, this.child, }) : assert(animation != null), assert(reverse != null); final Animation<double> animation; final Widget? child; final bool reverse; static final Animatable<double> _fadeInTransition = Tween<double>( begin: 0.0, end: 1.00, ).chain(CurveTween(curve: const Interval(0.125, 0.250))); static final Animatable<double> _scaleDownTransition = Tween<double>( begin: 1.10, end: 1.00, ).chain(_ZoomPageTransition._scaleCurveSequence); static final Animatable<double> _scaleUpTransition = Tween<double>( begin: 0.85, end: 1.00, ).chain(_ZoomPageTransition._scaleCurveSequence); static final Animatable<double?> _scrimOpacityTween = Tween<double?>( begin: 0.0, end: 0.60, ).chain(CurveTween(curve: const Interval(0.2075, 0.4175))); @override Widget build(BuildContext context) { double opacity = 0; // The transition's scrim opacity only increases on the forward transition. // In the reverse transition, the opacity should always be 0.0. // // Therefore, we need to only apply the scrim opacity animation when // the transition is running forwards. // // The reason that we check that the animation's status is not `completed` // instead of checking that it is `forward` is that this allows // the interrupted reversal of the forward transition to smoothly fade // the scrim away. This prevents a disjointed removal of the scrim. if (!reverse && animation.status != AnimationStatus.completed) { opacity = _scrimOpacityTween.evaluate(animation)!; } final Animation<double> fadeTransition = reverse ? kAlwaysCompleteAnimation : _fadeInTransition.animate(animation); final Animation<double> scaleTransition = (reverse ? _scaleDownTransition : _scaleUpTransition ).animate(animation); return AnimatedBuilder( animation: animation, builder: (BuildContext context, Widget? child) { return ColoredBox( color: Colors.black.withOpacity(opacity), child: child, ); }, child: FadeTransition( opacity: fadeTransition, child: ScaleTransition(scale: scaleTransition, child: child), ), ); } } class _ZoomExitTransition extends StatelessWidget { const _ZoomExitTransition({ required this.animation, this.reverse = false, this.child, }) : assert(animation != null), assert(reverse != null); final Animation<double> animation; final bool reverse; final Widget? child; static final Animatable<double> _fadeOutTransition = Tween<double>( begin: 1.0, end: 0.0, ).chain(CurveTween(curve: const Interval(0.0825, 0.2075))); static final Animatable<double> _scaleUpTransition = Tween<double>( begin: 1.00, end: 1.05, ).chain(_ZoomPageTransition._scaleCurveSequence); static final Animatable<double> _scaleDownTransition = Tween<double>( begin: 1.00, end: 0.90, ).chain(_ZoomPageTransition._scaleCurveSequence); @override Widget build(BuildContext context) { final Animation<double> fadeTransition = reverse ? _fadeOutTransition.animate(animation) : kAlwaysCompleteAnimation; final Animation<double> scaleTransition = (reverse ? _scaleDownTransition : _scaleUpTransition ).animate(animation); return FadeTransition( opacity: fadeTransition, child: ScaleTransition(scale: scaleTransition, child: child), ); } } /// Used by [PageTransitionsTheme] to define a [MaterialPageRoute] page /// transition animation. /// /// Apps can configure the map of builders for [ThemeData.pageTransitionsTheme] /// to customize the default [MaterialPageRoute] page transition animation /// for different platforms. /// /// See also: /// /// * [FadeUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android O. /// * [OpenUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android P. /// * [ZoomPageTransitionsBuilder], which defines the default page transition /// that's similar to the one provided in Android Q. /// * [CupertinoPageTransitionsBuilder], which defines a horizontal page /// transition that matches native iOS page transitions. abstract class PageTransitionsBuilder { /// Abstract const constructor. This constructor enables subclasses to provide /// const constructors so that they can be used in const expressions. const PageTransitionsBuilder(); /// Wraps the child with one or more transition widgets which define how [route] /// arrives on and leaves the screen. /// /// The [MaterialPageRoute.buildTransitions] method looks up the current /// current [PageTransitionsTheme] with `Theme.of(context).pageTransitionsTheme` /// and delegates to this method with a [PageTransitionsBuilder] based /// on the theme's [ThemeData.platform]. Widget buildTransitions<T>( PageRoute<T> route, BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child, ); } /// Used by [PageTransitionsTheme] to define a vertically fading /// [MaterialPageRoute] page transition animation that looks like /// the default page transition used on Android O. /// /// The animation fades the new page in while translating it upwards, /// starting from about 25% below the top of the screen. /// /// See also: /// /// * [OpenUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android P. /// * [ZoomPageTransitionsBuilder], which defines the default page transition /// that's similar to the one provided in Android Q. /// * [CupertinoPageTransitionsBuilder], which defines a horizontal page /// transition that matches native iOS page transitions. class FadeUpwardsPageTransitionsBuilder extends PageTransitionsBuilder { /// Constructs a page transition animation that slides the page up. const FadeUpwardsPageTransitionsBuilder(); @override Widget buildTransitions<T>( PageRoute<T>? route, BuildContext? context, Animation<double> animation, Animation<double>? secondaryAnimation, Widget child, ) { return _FadeUpwardsPageTransition(routeAnimation: animation, child: child); } } /// Used by [PageTransitionsTheme] to define a vertical [MaterialPageRoute] page /// transition animation that looks like the default page transition /// used on Android P. /// /// See also: /// /// * [FadeUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android O. /// * [ZoomPageTransitionsBuilder], which defines the default page transition /// that's similar to the one provided in Android Q. /// * [CupertinoPageTransitionsBuilder], which defines a horizontal page /// transition that matches native iOS page transitions. class OpenUpwardsPageTransitionsBuilder extends PageTransitionsBuilder { /// Constructs a page transition animation that matches the transition used on /// Android P. const OpenUpwardsPageTransitionsBuilder(); @override Widget buildTransitions<T>( PageRoute<T>? route, BuildContext? context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child, ) { return _OpenUpwardsPageTransition( animation: animation, secondaryAnimation: secondaryAnimation, child: child, ); } } /// Used by [PageTransitionsTheme] to define a zooming [MaterialPageRoute] page /// transition animation that looks like the default page transition used on /// Android Q. /// /// See also: /// /// * [FadeUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android O. /// * [OpenUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android P. /// * [CupertinoPageTransitionsBuilder], which defines a horizontal page /// transition that matches native iOS page transitions. class ZoomPageTransitionsBuilder extends PageTransitionsBuilder { /// Constructs a page transition animation that matches the transition used on /// Android Q. const ZoomPageTransitionsBuilder(); @override Widget buildTransitions<T>( PageRoute<T>? route, BuildContext? context, Animation<double> animation, Animation<double> secondaryAnimation, Widget? child, ) { return _ZoomPageTransition( animation: animation, secondaryAnimation: secondaryAnimation, child: child, ); } } /// Used by [PageTransitionsTheme] to define a horizontal [MaterialPageRoute] /// page transition animation that matches native iOS page transitions. /// /// See also: /// /// * [FadeUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android O. /// * [OpenUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android P. /// * [ZoomPageTransitionsBuilder], which defines the default page transition /// that's similar to the one provided in Android Q. class CupertinoPageTransitionsBuilder extends PageTransitionsBuilder { /// Constructs a page transition animation that matches the iOS transition. const CupertinoPageTransitionsBuilder(); @override Widget buildTransitions<T>( PageRoute<T> route, BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child, ) { return CupertinoRouteTransitionMixin.buildPageTransitions<T>(route, context, animation, secondaryAnimation, child); } } /// Defines the page transition animations used by [MaterialPageRoute] /// for different [TargetPlatform]s. /// /// The [MaterialPageRoute.buildTransitions] method looks up the current /// current [PageTransitionsTheme] with `Theme.of(context).pageTransitionsTheme` /// and delegates to [buildTransitions]. /// /// If a builder with a matching platform is not found, then the /// [FadeUpwardsPageTransitionsBuilder] is used. /// /// See also: /// /// * [ThemeData.pageTransitionsTheme], which defines the default page /// transitions for the overall theme. /// * [FadeUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android O. /// * [OpenUpwardsPageTransitionsBuilder], which defines a page transition /// that's similar to the one provided by Android P. /// * [ZoomPageTransitionsBuilder], which defines the default page transition /// that's similar to the one provided by Android Q. /// * [CupertinoPageTransitionsBuilder], which defines a horizontal page /// transition that matches native iOS page transitions. @immutable class PageTransitionsTheme with Diagnosticable { /// Constructs an object that selects a transition based on the platform. /// /// By default the list of builders is: [ZoomPageTransitionsBuilder] /// for [TargetPlatform.android], and [CupertinoPageTransitionsBuilder] for /// [TargetPlatform.iOS] and [TargetPlatform.macOS]. const PageTransitionsTheme({ Map<TargetPlatform, PageTransitionsBuilder> builders = _defaultBuilders }) : _builders = builders; static const Map<TargetPlatform, PageTransitionsBuilder> _defaultBuilders = <TargetPlatform, PageTransitionsBuilder>{ TargetPlatform.android: ZoomPageTransitionsBuilder(), TargetPlatform.iOS: CupertinoPageTransitionsBuilder(), TargetPlatform.macOS: CupertinoPageTransitionsBuilder(), }; /// The [PageTransitionsBuilder]s supported by this theme. Map<TargetPlatform, PageTransitionsBuilder> get builders => _builders; final Map<TargetPlatform, PageTransitionsBuilder> _builders; /// Delegates to the builder for the current [ThemeData.platform] /// or [ZoomPageTransitionsBuilder]. /// /// [MaterialPageRoute.buildTransitions] delegates to this method. Widget buildTransitions<T>( PageRoute<T> route, BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child, ) { TargetPlatform platform = Theme.of(context).platform; if (CupertinoRouteTransitionMixin.isPopGestureInProgress(route)) platform = TargetPlatform.iOS; final PageTransitionsBuilder matchingBuilder = builders[platform] ?? const ZoomPageTransitionsBuilder(); return matchingBuilder.buildTransitions<T>(route, context, animation, secondaryAnimation, child); } // Just used to the builders Map to a list with one PageTransitionsBuilder per platform // for the operator == overload. List<PageTransitionsBuilder?> _all(Map<TargetPlatform, PageTransitionsBuilder> builders) { return TargetPlatform.values.map((TargetPlatform platform) => builders[platform]).toList(); } @override bool operator ==(Object other) { if (identical(this, other)) return true; if (other.runtimeType != runtimeType) return false; if (other is PageTransitionsTheme && identical(builders, other.builders)) return true; return other is PageTransitionsTheme && listEquals<PageTransitionsBuilder?>(_all(other.builders), _all(builders)); } @override int get hashCode => Object.hashAll(_all(builders)); @override void debugFillProperties(DiagnosticPropertiesBuilder properties) { super.debugFillProperties(properties); properties.add( DiagnosticsProperty<Map<TargetPlatform, PageTransitionsBuilder>>( 'builders', builders, defaultValue: PageTransitionsTheme._defaultBuilders, ), ); } }