How to change navigation animation using Flutter

You can achieve this by using CupertinoPageRoute. Please check the below code.

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


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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Transition Animation Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new FirstPage(),
    );
  }
}

class FirstPage extends StatefulWidget {
  @override
  _FirstPageState createState() => new _FirstPageState();
}

class _FirstPageState extends State<FirstPage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('First Page'),
      ),
      body: new Center(
        child: new RaisedButton(
          child: new Text('Goto Second Page'),
          onPressed: () {
            Navigator.of(context).push(new SecondPageRoute());
          },
        ),
      ),
    );
  }
}

class SecondPageRoute extends CupertinoPageRoute {
  SecondPageRoute()
      : super(builder: (BuildContext context) => new SecondPage());


  // OPTIONAL IF YOU WISH TO HAVE SOME EXTRA ANIMATION WHILE ROUTING
  @override
  Widget buildPage(BuildContext context, Animation<double> animation,
      Animation<double> secondaryAnimation) {
    return new FadeTransition(opacity: animation, child: new SecondPage());
  }
}

class SecondPage extends StatefulWidget {
  @override
  _SecondPageState createState() => new _SecondPageState();
}

class _SecondPageState extends State<SecondPage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Second Page'),
      ),
      body: new Center(
        child: new Text('This is the second page'),
      ),
    );
  }
}

Some play-around with animation

  // OPTIONAL IF YOU WISH TO HAVE SOME EXTRA ANIMATION WHILE ROUTING
  @override
  Widget buildPage(BuildContext context, Animation<double> animation,
      Animation<double> secondaryAnimation) {
    return new RotationTransition(
        turns: animation,
        child: new ScaleTransition(
          scale: animation,
          child: new FadeTransition(
            opacity: animation,
            child: new SecondPage(),
          ),
        ));
  }

I have done this by providing my own builders with custom map in pageTransitionsTheme for the app level theme.

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Startup Name Generator Tile',
      home: RandomWords(),
      theme: new ThemeData(
        primaryColor: Colors.white,
        // Add the line below to get horizontal sliding transitions for routes.
        pageTransitionsTheme: PageTransitionsTheme(builders: {TargetPlatform.android: CupertinoPageTransitionsBuilder(),}),
      ),
    );
  }
}

Of course, I didn't add a map entry for ios as I use only android for TargetPlatform.

You can use PageRouteBuilder.

The following example shows FadeTransition when you navigate to second screen.

Navigator.push(
  context,
  PageRouteBuilder(
    pageBuilder: (_, __, ___) => Page2(),
    transitionDuration: Duration(seconds: 2),
    transitionsBuilder: (_, a, __, c) => FadeTransition(opacity: a, child: c),
  ),
);

---

If you're using go_router:

GoRoute(
  path: '/page2',
  pageBuilder: (_, state) {
    return CustomTransitionPage(
      key: state.pageKey,
      child: Page2(),
      transitionDuration: Duration(seconds: 2),
      transitionsBuilder: (_, a, __, c) => FadeTransition(opacity: a, child: c),
    );
  },
)

and then:

context.go('/page2');

You can subclass MaterialPageRouteand override buildTransitions.

Eg:

class MyCustomRoute<T> extends MaterialPageRoute<T> {
  MyCustomRoute({ WidgetBuilder builder, RouteSettings settings })
      : super(builder: builder, settings: settings);

  @override
  Widget buildTransitions(BuildContext context,
      Animation<double> animation,
      Animation<double> secondaryAnimation,
      Widget child) {
    if (settings.isInitialRoute)
      return child;
    // Fades between routes. (If you don't want any animation,
    // just return child.)
    return new FadeTransition(opacity: animation, child: child);
  }
}

to use :

new RaisedButton(
                child: new Text('Goto'),
                onPressed: (){
                  Navigator.push(
                    context,
                    new MyCustomRoute(builder: (context) => new SecondPage()),
                  );
                }),

Replace fade transition with your animation