Flutter使用flutter_bluetooth_serial连接设备抛出java.io.IOException错误

错误详情 #

PlatformException(connect_error, read failed, socket might closed or timeout, read ret: -1, java.io.IOException: read failed, socket might closed or timeout, read ret: -1
          at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:952)
          at android.bluetooth.BluetoothSocket.readInt(BluetoothSocket.java:966)
          at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:522)
at io.github.edufolly.flutterbluetoothserial.BluetoothConnection.connect(BluetoothConnection.java:57)
at io.github.edufolly.flutterbluetoothserial.BluetoothConnection.connect(BluetoothConnection.java:64)
at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin$FlutterBluetoothSerialMethodCallHandler.lambda$onMethodCall$4$io-github-edufolly-flutterbluetoothserial-FlutterBluetoothSerialPlugin$FlutterBluetoothSerialMethodCallHandler(FlutterBluetoothSerialPlugin.java:1007)
at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin$FlutterBluetoothSerialMethodCallHandler$$ExternalSyntheticLambda7.r

连接多款不同蓝牙设备均触发该错误。

触发错误的代码 #

List<BluetoothDevice> bondedDevices = await fbs.getBondedDevices();
for(BluetoothDevice device in bondedDevices.where((x)=>x.address == device.device.address)){
  BluetoothConnection.toAddress(device.address).then(
    (connection){
      print('connected');
      _connection =connection;
    }
  ).catchError((onError)=>{
    print("caughtError:"),
    print(onError)
  });
}

问题修复步骤 #

• 修正过滤逻辑错误：代码里的x.address == device.device.address存在逻辑问题，device是循环变量，device.device未定义，相当于用空值匹配设备地址，根本找不到目标设备。替换为实际要连接的设备MAC地址：

  // 替换成你要连接的设备MAC地址
  const targetMac = "XX:XX:XX:XX:XX:XX";
  final bondedDevices = await fbs.getBondedDevices();
  for (final device in bondedDevices.where((d) => d.address == targetMac)) {
    try {
      final connection = await BluetoothConnection.toAddress(device.address);
      print('connected');
      _connection = connection;
    } catch (e) {
      print("caughtError: $e");
    }
  }
  

• 补全蓝牙权限：Android端必须配置足够的权限，在AndroidManifest.xml里添加：

  <uses-permission android:name="android.permission.BLUETOOTH" />
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
  <!-- Android 12及以上额外需要 -->
  <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
  <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
  

  同时要在代码中动态申请这些权限，否则系统会拒绝蓝牙操作。
• 检查设备状态：确保手机蓝牙已开启，目标设备处于可连接状态（未被其他设备占用、电量充足）。
• 添加超时控制：给连接操作设置超时，避免长时间卡在等待状态：

  try {
    final connection = await BluetoothConnection.toAddress(device.address)
        .timeout(const Duration(seconds: 10));
    print('connected');
    _connection = connection;
  } on TimeoutException catch (_) {
    print("连接超时");
  } catch (e) {
    print("caughtError: $e");
  }
  

非BLE蓝牙替代库 #

• flutter_blue_plus：社区活跃度高，支持经典蓝牙（部分功能）和BLE，维护更新及时。
• bluetooth_serial_port：专注经典蓝牙串口通信，API简洁，适配安卓和iOS平台。
• flutter_bluetooth：覆盖经典蓝牙的搜索、配对、连接、数据传输全流程，功能完整。

内容的提问来源于stack exchange，提问作者JokeyLo