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我的程序与充当服务器的嵌入式蓝牙设备连接。我成功找到了附近的蓝牙设备，但是当我尝试连接到新设备时，我的程序在调用 BluetoothSocket.connect() 时由于 IO 异常而崩溃。我无法弄清楚发生了什么，所以如果有人可以帮助我，我会非常感激。

我认为这可能与我随机生成的 UUID 有关，但我并不完全确定。

谢谢。

    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    btnScanDevice = (Button) findViewById( R.id.scandevice );

    stateBluetooth = (TextView) findViewById( R.id.bluetoothstate );
    startBluetooth();

    listDevicesFound = (ListView) findViewById( R.id.devicesfound );
    btArrayAdapter = new ArrayAdapter<String>( AndroidBluetooth.this,
            android.R.layout.simple_list_item_1 );
    listDevicesFound.setAdapter( btArrayAdapter );

    CheckBlueToothState();

    btnScanDevice.setOnClickListener( btnScanDeviceOnClickListener );

    registerReceiver( ActionFoundReceiver, new IntentFilter( BluetoothDevice.ACTION_FOUND ) );

    listDevicesFound.setOnItemClickListener( new OnItemClickListener()
    {
      public void onItemClick(AdapterView<?> arg0, View arg1,int arg2, long arg3) 
      {
          myBtDevice = btDevicesFound.get( arg2 );
          try {
              btSocket = myBtDevice.createRfcommSocketToServiceRecord( MY_UUID );
              iStream = btSocket.getInputStream();
              oStream = btSocket.getOutputStream();
          } catch ( IOException e ) {
              Log.e( "Bluetooth Socket", "Bluetooth not available, or insufficient permissions" );
          } catch ( NullPointerException e ) {
              Log.e( "Bluetooth Socket", "Null Pointer One" );
          }
          myBtAdapter.cancelDiscovery();
          CheckBlueToothState();
          try {
              btSocket.connect();
          } catch ( IOException e ) {
              Log.e( "Bluetooth Socket", "IO Exception" );
          } catch ( NullPointerException e ) {
              Log.e( "Bluetooth Socket", "Null Pointer Two" );
          }
      } 

  });
}

private void CheckBlueToothState() {
    if( myBtAdapter == null ) {
        stateBluetooth.setText("Bluetooth NOT supported" );
    } else {
        if( myBtAdapter.isEnabled() ) {
            if( myBtAdapter.isDiscovering() ) {
                stateBluetooth.setText( "Bluetooth is currently " +
                        "in device discovery process." );
            } else {
                stateBluetooth.setText( "Bluetooth is Enabled." );
                btnScanDevice.setEnabled( true );
            }
        } else {
            stateBluetooth.setText( "Bluetooth is NOT enabled" );
            Intent enableBtIntent = new Intent( BluetoothAdapter.ACTION_REQUEST_ENABLE );
            startActivityForResult( enableBtIntent, REQUEST_ENABLE_BT );
        }
    }
}

private Button.OnClickListener btnScanDeviceOnClickListener = new Button.OnClickListener() {
    public void onClick( View arg0 ) {
        btArrayAdapter.clear();
        myBtAdapter.startDiscovery();
    }
};


@Override
protected void onActivityResult( int requestCode, int resultCode, Intent data ) {
    if( requestCode == REQUEST_ENABLE_BT ) {
        CheckBlueToothState();
    }
}

private final BroadcastReceiver ActionFoundReceiver = new BroadcastReceiver() {
    public void onReceive( Context context, Intent intent ) {
        String action = intent.getAction();
        if( BluetoothDevice.ACTION_FOUND.equals( action ) ) {
            BluetoothDevice btDevice = intent.getParcelableExtra( BluetoothDevice.EXTRA_DEVICE );
            btDevicesFound.add( btDevice );
            btArrayAdapter.add( btDevice.getName() + "\n" + btDevice.getAddress() );
            btArrayAdapter.notifyDataSetChanged();
        }           
    }
};
public static void startBluetooth(){
    try {
        myBtAdapter = BluetoothAdapter.getDefaultAdapter();
        myBtAdapter.enable();
    } catch ( NullPointerException ex ) {
        Log.e( "Bluetooth", "Device not available" );
    }
}

public static void stopBluetooth() {
    myBtAdapter.disable();
}
4

1 回答 1

4

您发布的代码有两个问题，但只有一个与您的崩溃有关。

您在 logcat 中的崩溃很可能会说“命令被拒绝”之类的内容。UUID 是一个必须指向嵌入式设备上已发布服务的值，它不能只是随机生成的。换句话说，您要访问的 RFCOMM SPP 连接具有特定的 UUID，它发布该 UUID 以标识该服务，并且当您创建套接字时，它必须使用匹配的 UUID。

我写的这篇博文可能会帮助您了解如何查询您的设备以获取需要插入到您的程序中的正确 UUID。在 Android 4.0 之前，SDK 几乎假定您提前知道它（您从蓝牙 OEM 等处获得它），因此从您的设备中发现它有点迂回。如果您有幸拥有 4.0.3 设备，fetchUuidsWithSdp()并且getUuids()现在是公共方法，您可以直接调用它们以查找所有已发布的服务及其关联的 UUID 值。

您的代码稍后可能会遇到的第二个问题是，在您连接之前，您无法从套接字获取数据流，因此您可能需要像这样重写您的方法：

      myBtDevice = btDevicesFound.get( arg2 );
      try {
          btSocket = myBtDevice.createRfcommSocketToServiceRecord( MY_UUID );
      } catch ( IOException e ) {
          Log.e( "Bluetooth Socket", "Bluetooth not available, or insufficient permissions" );
      }

      myBtAdapter.cancelDiscovery();
      CheckBlueToothState();
      try {
          btSocket.connect();
          //Get streams after connect() returns without error
          iStream = btSocket.getInputStream();
          oStream = btSocket.getOutputStream();
      } catch ( IOException e ) {
          Log.e( "Bluetooth Socket", "IO Exception" );
      } catch ( NullPointerException e ) {
          Log.e( "Bluetooth Socket", "Null Pointer Two" );
      }

高温高压

于 2012-06-12T14:58:46.587 回答