相較於一次性的非同步執行緒 FutureBuilder，StreamBuilder 能持續運作並可搭配 StreamController 達到更新畫面資料時，不需要整個重新 build 而只更動使用 StreamBuilder 的區塊。

以下StreamBuilder 範例為使用 dart_ping 套件，建立一個簡易的網址偵測 App。

程式規劃和引用的套件(pubspec.yaml)

main.dart

import 'package:flutter/material.dart';

import 'package:network_toolkit/screens/ping_screen.dart';

void main() {
  runApp(
    const AppEntryPoint()
  );
}

class AppEntryPoint extends StatelessWidget {
  const AppEntryPoint({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Network Toolkit',
      theme: ThemeData(
        useMaterial3: true,
        primarySwatch: Colors.green,
      ),
      routes: {
        "/ping":(BuildContext context) => const PingScreen(),
      },        
      initialRoute: "/ping",
    );
  }
}

screens/ping_screen.dart

import 'package:flutter/material.dart';
import 'dart:async';
import 'package:dart_ping/dart_ping.dart';

import 'package:network_toolkit/components/ping_result_component.dart';

class PingScreen extends StatefulWidget {
  const PingScreen({super.key});

  @override
  State createState() {
    return _PingScreen();
  }
}

class _PingScreen extends State<PingScreen> {
  bool _userInputTextFieldEnabled = true;
  String _urlOrIP = "";
  late StreamController _controller;
  final ScrollController _scrollController = ScrollController();
  List<String> _pingResultList = [];

  @override
  void initState() {
    super.initState();
    _controller = StreamController.broadcast(); // Initial
  }

  @override
  Widget build(BuildContext context) {
    var textEditController = TextEditingController( text: _urlOrIP );

    Widget userInputTextField = SizedBox(
      width: 500,
      child: TextField(
        decoration: const InputDecoration(
          border: OutlineInputBorder(),
          hintText: 'Input URL or IP',
        ),
        controller: textEditController,
        enabled: _userInputTextFieldEnabled,
        onSubmitted: (inputvalue){
          _urlOrIP = inputvalue;
          _pingResultList = [];
          
          setState(() {
            _userInputTextFieldEnabled = false;
          });

          // Begin ping process and listen for output
          final ping = Ping(_urlOrIP, count: 5);          
          ping.stream.listen(
            (event) {
              _pingResultList.add("${ping.command} : ${event.toString()}");
              
              _controller.sink.add(_pingResultList);
            },          
            onDone: () {
              setState(() {
                _userInputTextFieldEnabled = true;                
              });
            },
          );
        },
      ),
    );

    return Scaffold(
      appBar: AppBar(
        title: const Text("Ping"),
      ),
      body: Column(
        children: [
          userInputTextField,
          StreamBuilder(
            initialData: _pingResultList,
            stream: _controller.stream,
            builder: (context, n) {
              List<String> results = n.data as List<String>;
              return Expanded(
                child: ListView(
                  controller: _scrollController,
                  children: [
                    ...results.map((pingResult) => PingResultComponent(pingResult)).toList()
                  ]
                )
              );
            }
          ),
        ]
      ),
    );
  }
  
  @override
  void dispose() {
    super.dispose();
    _controller.close();
  }
}

components/ping_result_component.dart

import 'package:flutter/material.dart';

// ignore: must_be_immutable
class PingResultComponent extends StatefulWidget {
  String pingResult;

  PingResultComponent(this.pingResult, {super.key});

  @override
  State createState() {
    return _PingResultComponent();
  }
}

class _PingResultComponent extends State<PingResultComponent> {
  @override
  Widget build(BuildContext context) {
    Widget pingResultValueText = 
    Flexible(
      child: Text(
        widget.pingResult,
      )
    );

    return Card(
      child: ListTile(
        title: Row(
          children: [
            pingResultValueText,
          ]
        ),
      ),
    );
  }
}