在下面实现的代码中，我可以在页面底部显示带有 Fade 动画的对话框，现在，我想将 SlideTransition 添加到 ModalRoute这个实现从底部滑动对话框，但我不能那样做

例如，我想要的是:

源代码:

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Open the popup window',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          showPopup(context, _popupBody(), 'Popup Demo');
        },
        tooltip: 'Open Popup',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  showPopup(BuildContext context, Widget widget, String title, {BuildContext popupContext}) {
    Navigator.push(
      context,
      PopupLayout(
        top: MediaQuery.of(context).size.height * 0.300,
        left: 0,
        right: 0,
        bottom: 0,
        child: PopupContent(
          content: Scaffold(
            body: widget,
          ),
        ),
      ),
    );
  }

  Widget _popupBody() {
    return Container(
      child: Text('This is a popup window'),
    );
  }
}

class PopupLayout extends ModalRoute {
  double top;
  double bottom;
  double left;
  double right;
  Color bgColor;
  final Widget child;

  @override
  Duration get transitionDuration => Duration(milliseconds: 200);

  @override
  bool get opaque => false;

  @override
  bool get barrierDismissible => false;

  @override
  Color get barrierColor => bgColor == null ? Colors.black.withOpacity(0.5) : bgColor;

  @override
  String get barrierLabel => null;

  @override
  bool get maintainState => false;

  PopupLayout({Key key, this.bgColor, @required this.child, this.top, this.bottom, this.left, this.right});

  @override
  Widget buildPage(
    BuildContext context,
    Animation<double> animation,
    Animation<double> secondaryAnimation,
  ) {
    if (top == null) this.top = 10;
    if (bottom == null) this.bottom = 20;
    if (left == null) this.left = 20;
    if (right == null) this.right = 20;

    return GestureDetector(
      onTap: () {
        // call this method here to hide soft keyboard
        SystemChannels.textInput.invokeMethod('TextInput.hide');
      },
      child: Material(
        // This makes sure that text and other content follows the material style
        type: MaterialType.transparency,
        //type: MaterialType.canvas,
        // make sure that the overlay content is not cut off
        child: SafeArea(
          bottom: true,
          child: _buildOverlayContent(context),
        ),
      ),
    );
  }

  Widget _buildOverlayContent(BuildContext context) {
    return Container(
      margin: EdgeInsets.only(bottom: this.bottom, left: this.left, right: this.right, top: this.top),
      child: SlideTransition(child: child),
    );
  }

  @override
  Widget buildTransitions(BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child) {
    return FadeTransition(opacity: animation, child: child);
  }
}

class PopupContent extends StatefulWidget {
  final Widget content;

  PopupContent({
    Key key,
    this.content,
  }) : super(key: key);

  _PopupContentState createState() => _PopupContentState();
}

class _PopupContentState extends State<PopupContent> {
  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: widget.content,
    );
  }
}

最佳答案

这是一个工作示例

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage>
    with TickerProviderStateMixin {

  void showPopup() {
    AnimationController controller = AnimationController(
        duration: const Duration(milliseconds: 400), vsync: this);
    showDialog(
      context: context,
      builder: (_) => PopUp(
        controller: controller,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: showPopup,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class PopUp extends StatefulWidget {
  final AnimationController controller;

  PopUp({this.controller});

  @override
  State<StatefulWidget> createState() => PopUpState();
}

class PopUpState extends State<PopUp> {
  Animation<double> opacityAnimation;
  Tween<double> opacityTween = Tween<double>(begin: 0.0, end: 1.0);
  Tween<double> marginTopTween = Tween<double>(begin: 600, end: 200);
  Animation<double> marginTopAnimation;
  AnimationStatus animationStatus;

  @override
  void initState() {
    super.initState();

    marginTopAnimation = marginTopTween.animate(widget.controller)
      ..addListener(() {
        animationStatus = widget.controller.status;

        if (animationStatus == AnimationStatus.dismissed) {
          Navigator.of(context).pop();
        }

        if(this.mounted) {
          setState(() {

          });
        }
      });
    widget.controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return FadeTransition(
      opacity: opacityTween.animate(widget.controller),
      child: GestureDetector(
        onTap: () {
          widget.controller.reverse();
        },
        child: Material(
          color: Colors.transparent,
          child: Container(
            margin: EdgeInsets.only(
              top: marginTopAnimation.value,
            ),
            color: Colors.red,
            child: Text("Container"),
          ),
        ),
      ),
    );
  }

  @override
  void dispose() {
    widget.controller.dispose();
    super.dispose();
  }
}

更新 1:添加了 Material 作为 Container 的子项以修复 barrier not dismissing 错误。

更新 2:进行了一些更改，在障碍物消失时反转动画。

注意:屏幕截图未反射(reflect)更新的更改。这是原始答案的演示。

关于Flutter 添加自定义 SlideTransition 到 ModalRoute，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57035483/