创建两个Flutter页面，FirstScreen与SecondScreen

使用 Navigator.push()方法导航到下一界面

使用 Navigator.pop()方法返回到上一个界面

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    title: 'Navigation Basics',
    home: FirstScreen(),
  ));
}

class FirstScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('First Screen'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Launch screen'),
          onPressed: () {
            Navigator.push( //跳转到第二个界面
              context,
              MaterialPageRoute(builder: (context) => SecondScreen()),
            );
          },
        ),
      ),
    );
  }
}

class SecondScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Second Screen"),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () {
            Navigator.pop(context);//从第二个界面返回
          },
          child: Text('Go back!'),
        ),
      ),
    );
  }
}