这是使用流的可能解决方案：
import 'dart:async';import 'package:flutter/material.dart';void main() => runApp(new MyApp());class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return new MaterialApp( title: 'Timer', theme: new ThemeData( primaryColor: Colors.grey.shade800, ), home: new MyHomePage(), ); }}class MyHomePage extends StatelessWidget { StreamController<int> _controller = StreamController<int>(); int _seconds = 1; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text("title"), ), body: Column( mainAxisAlignment: MainAxisAlignment.spaceAround, children: <Widget>[ MyTextWidget(stream: _controller.stream), //just update this widget Divider(), Row( mainAxisAlignment: MainAxisAlignment.spaceAround, children: <Widget>[ IconButton( icon: Icon(Icons.add_circle), onPressed: _addPressed, iconSize: 150.0, ), IconButton( icon: Icon(Icons.remove_circle), onPressed: ()=> _controller.add(_seconds++), iconSize: 150.0, ), ], ) ], ), ); } void _addPressed() { //somehow call _updateSeconds() }}class MyTextWidget extends StatefulWidget{ final Stream<int> stream; MyTextWidget({this.stream}); @override _MyTextWidgetState createState() => _MyTextWidgetState();}class _MyTextWidgetState extends State<MyTextWidget> { int secondsToDisplay = 0; void _updateSeconds(int newSeconds) { setState(() { secondsToDisplay = newSeconds; }); } @override void initState() { super.initState(); widget.stream.listen((seconds) { _updateSeconds(seconds); }); } @override Widget build(BuildContext context) { return Text( secondsToDisplay.toString(), textScaleFactor: 5.0, ); }}
