flutter, 在当前页刷新前一页

import 'package:flutter/material.dart';
 
void main() {
  runApp(MyApp());
}
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Refresh on Go Back',
      home: HomePage(),
    );
  }
}
 
class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}
 
class _HomePageState extends State<HomePage> {
  int id = 0;
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Text(
              'Data: $id',
              style: Theme.of(context).textTheme.headline5,
            ),
            MaterialButton(
              child: Text('Second Page'),
              onPressed: navigateSecondPage,
            ),
          ],
        ),
      ),
    );
  }
 
  void refreshData() {
    id++;
  }
 
  onGoBack(dynamic value) {
    refreshData();
    setState(() {});
  }
 
  void navigateSecondPage() {
    Route route = MaterialPageRoute(builder: (context) => SecondPage());
    Navigator.push(context, route).then(onGoBack);
  }
}
 
class SecondPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Second Page'),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () {
            Navigator.pop(context);
          },
          child: Text('Go Back'),
        ),
      ),
    );
  }
}