flutter使用flutter_ble_plus插件运用流的方式,显示蓝牙扫描结果页面

import 'package:flutter/material.dart';
import 'package:flutter_ble_plus/flutter_ble_plus.dart';
 
class BluetoothScanPage extends StatefulWidget {
  @override
  _BluetoothScanPageState createState() => _BluetoothScanPageState();
}
 
class _BluetoothScanPageState extends State<BluetoothScanPage> {
  Stream<BluetoothScanResult>? _scanStream;
  bool _isScanning = false;
 
  void startScan() async {
    if (_isScanning) return;
    setState(() {
      _isScanning = true;
    });
    _scanStream = FlutterBlePlus.scanResults.doOnDone(() {
      setState(() {
        _isScanning = false;
      });
    });
    await FlutterBlePlus.startScan(timeout: 5);
  }
 
  void stopScan() async {
    await FlutterBlePlus.stopScan();
    setState(() {
      _scanStream = null;
      _isScanning = false;
    });
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('蓝牙扫描结果'),
        actions: [
          IconButton(
            icon: Icon(_isScanning ? Icons.stop : Icons.search),
            onPressed: _isScanning ? stopScan : startScan,
          ),
        ],
      ),
      body: StreamBuilder<BluetoothScanResult>(
        stream: _scanStream,
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.active) {
            final results = snapshot.data?.results ?? [];
            return ListView.builder(
              itemCount: results.length,
              itemBuilder: (context, index) {
                final result = results[index];
                return ListTile(
                  title: Text(result.device.name ?? 'Unknown Device'),
                  subtitle: Text(result.device.id.toString()),
                  // 可以在这里添加更多的设备信息
                );
              },
            );
          }
          return Center(
            child: _isScanning
                ? CircularProgressIndicator()
                : Text('Press search button to start scanning'),
          );
        },
      ),
    );
  }
}

这段代码首先定义了一个BluetoothScanPage页面，它使用StreamBuilder来构建界面，以便实时显示扫描结果。startScan方法开始扫描，stopScan方法停止扫描，并通过_isScanning标志控制搜索按钮的状态。扫描结果通过_scanStream这个Stream<BluetoothScanResult>进行展示，其中BluetoothScanResult是扫描结果的类型。这个例子展示了如何在Flutter中使用流的方式来处理蓝牙设备的扫描结果，并且实现了界面的实时更新。