使用不带按钮的Navigator类(即onPressed...)在void方法中

import 'package:flutter/material.dart';

void navigateToNextPage(BuildContext context) {
  Navigator.push(
    context,
    MaterialPageRoute(builder: (context) => NextPage()),
  );
}

class NextPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Next Page'),
      ),
      body: Center(
        child: Text('This is the next page.'),
      ),
    );
  }
}

FlatButton(
  child: Text('Go to Next Page'),
  onPressed: () {
    navigateToNextPage(context);
  },
),