Flutter蓝牙设备连接失败：Android错误码133求助

我在开发蓝牙设备连接功能时，能正常获取周边可用设备列表，但点击设备后无法完成连接，出现以下错误：

FlutterBluePlusException | connect | android-code: 133 | ANDROID_SPECIFIC_ERROR

相关代码 #

状态类定义

import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';
import 'package:hydration_monitor/Helper/CustomWidgets.dart';
import 'dart:io' show Platform;

class BluetoothScreen extends StatefulWidget {
 const BluetoothScreen({Key? key}) : super(key: key);

 @override
 State<BluetoothScreen> createState() => _BluetoothScreenState();
}

class _BluetoothScreenState extends State<BluetoothScreen> {
 bool isScan = false;
 List deviceDataSend =[];
 BluetoothDevice? connectedDevice;

扫描设备代码

void startScanning() async {
deviceDataSend.clear();
setState(() {
  isScan = true;
});
await FlutterBluePlus.startScan();
FlutterBluePlus.onScanResults.listen((results) {
  for (ScanResult result in results) {
    bool isDuplicate = deviceDataSend.any((device) => device['remoteId'] == result.device.remoteId);
    if (!isDuplicate) {
      if (!deviceDataSend.contains(result.device)) {
        setState(() {
          deviceDataSend.add(result.device);
        });
      }
    }
  }
});
}

停止扫描代码

stopScan()async{
setState(() {
  isScan = false;
});
await FlutterBluePlus.stopScan();
}

设备连接代码

connectDevice(BluetoothDevice device)async{
try {
  await device.connect();
} catch (e) {
  print("Error connecting to device: $e");
}
}

页面构建代码

@override
Widget build(BuildContext context) {
double _height = MediaQuery.of(context).size.height;
double _width = MediaQuery.of(context).size.width;
return Scaffold(
  appBar: BaseAppBar(
    appBar: AppBar(),
    title: CustomLabelText(Text: "BluetoothScreen",bgColor: Colors.white,size: _width / 22,Bold: true),
  ),
  body: BgContainer(
    child: Stack(
      children: [
        Padding(
          padding:  EdgeInsets.symmetric(horizontal: _width / 25),
          child: Column(
            children: [
              SizedBox(height: _height / 35,),
              isScan ? CustomButton(Text: 'Stop', width: 3, button: (){stopScan();},) :
              CustomButton(Text: 'Pair', width: 3, button: (){startScanning();},),
              SizedBox(height: _height / 35,),
              Divider(),
              Container(
                height: _height / 1.5,
                child: ListView.builder(
                  shrinkWrap: true,
                  itemCount: deviceDataSend.length,
                  itemBuilder: (context, index) {
                    return ListTile(
                      onTap: (){
                        connectDevice(deviceDataSend[index]);
                      },
                      title: CustomLabelText(
                        Text: deviceDataSend[index]['remoteId'].toString(),
                      ),
                      trailing: CustomLabelText(
                        Text: deviceDataSend[index]['platformName'],
                      ),
                    );
                  },
                )
              )
            ],
          ),
        )
      ],
    ),
  ),
);
}
}

解决方案 #

• 连接前必须停止扫描：Android系统中，蓝牙扫描会占用底层资源，不停止扫描直接连接大概率会失败。修改连接方法，先停止扫描再执行连接：

  connectDevice(BluetoothDevice device) async {
    if (isScan) {
      await stopScan();
    }
    try {
      await device.connect(
        autoConnect: false,
        timeout: const Duration(seconds: 10),
      );
      setState(() {
        connectedDevice = device;
      });
    } catch (e) {
      print("Error connecting to device: $e");
    }
  }
  

• 修正扫描重复判断逻辑：原代码中用deviceDataSend.contains(result.device)判断重复不准确，因为对象引用不同，改用设备唯一标识remoteId判断：

  void startScanning() async {
    deviceDataSend.clear();
    setState(() {
      isScan = true;
    });
    // 添加扫描超时，避免持续扫描占用资源
    await FlutterBluePlus.startScan(timeout: const Duration(seconds: 10));
    FlutterBluePlus.onScanResults.listen((results) {
      for (ScanResult result in results) {
        bool isDuplicate = deviceDataSend.any((existingDevice) => 
          (existingDevice as BluetoothDevice).remoteId == result.device.remoteId
        );
        if (!isDuplicate) {
          setState(() {
            deviceDataSend.add(result.device);
          });
        }
      }
    });
  }
  

• 检查权限与蓝牙状态：Android 12及以上版本，需在AndroidManifest.xml中申请BLUETOOTH_SCAN、BLUETOOTH_CONNECT权限，并且确保设备蓝牙处于开启状态。

• 处理设备配对需求：如果目标蓝牙设备需要配对，需提前在系统设置完成配对，或者监听FlutterBluePlus的配对请求事件，在App内处理配对流程。

内容的提问来源于stack exchange，提问作者Ah Zeem khatib