Question

我正在努力解决蓝牙应用程序的一些问题。该应用程序通过蓝牙连接到OBD2接口，我的目标是从我的汽车接收一些数据，如速度，RPM等。我制作了一个带有按钮的应用程序当我点击它时，我向OBD2界面发送一条消息，我得到了回复。但我的目标是不断收到这些数据。所以我发现我可以在里面做到这一点 onResume()方法。下面是发送消息的简单代码。

@Override
protected void onResume() {
    super.onResume();

    HandlerDelay.postDelayed(new Runnable() {
        @Override
        public void run() {
            checkSPDstatus();

        }
    },500);
}

private void checkSPDstatus(){

    if (mmSocket != null){

        try {
            mmSocket.getOutputStream().write("010C\r".getBytes());
        } catch (IOException e) {

            Log.e("Status", String.valueOf(e));
        }

    }
}

但使用我的应用程序崩溃，甚至无法连接BT设备.. 使用AsyncTask通过BT Im连接我的应用程序。我将不胜感激任何帮助。

关心马特。

Answer 1

好的，我想出了如何做到这一点。我使用Service来连接蓝牙设备而不是AsyncTask。我使用了两个处理程序。现在一切正常。我可以每500ms发送一次String消息，也可以从OBD2接口获得响应。以下是服务类的代码。我使用BroadcastReceiver从Service接收数据到我的UI。

public class BTConnect extends Service {

    private BluetoothAdapter btAdapter;
    private String adress;
    private static UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
    private BluetoothSocket mmSocket;
    private boolean isBTConnected = false;
    private ConnectedThread mConncetedThread;
    Handler h;
    Handler HandlerDelay = new Handler();
    final int handlerState = 0;
    public StringBuilder recDataString = new StringBuilder();
    private Timer mTimer;
    final static String MY_ACTION = "MY_ACTION";


    public BTConnect() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }


    @Override
    public void onCreate() {
        super.onCreate();

        if(mTimer != null) {

            mTimer.cancel();

        } else {

            mTimer = new Timer();
        }

        mTimer.scheduleAtFixedRate(new TimerDisplay(), 0, 500);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        String adressMac = intent.getStringExtra("MAC_ADRESS");

        // Trzeba sie połączyć

        h = new MyHandler();

        tryToConnect(adressMac);

        return START_NOT_STICKY;
    }



    private void tryToConnect(String address) {

        try {
            if (mmSocket == null || !isBTConnected) {

                btAdapter = BluetoothAdapter.getDefaultAdapter();

                BluetoothDevice device = btAdapter.getRemoteDevice(address);

                mmSocket = device.createInsecureRfcommSocketToServiceRecord(myUUID);

                BluetoothAdapter.getDefaultAdapter().cancelDiscovery();

                mmSocket.connect();

                isBTConnected = true;

                mConncetedThread = new ConnectedThread(mmSocket);
                mConncetedThread.start();


            }


        } catch (IOException e) {

            Log.e("Error", String.valueOf(e));

        }

            if (isBTConnected) {

                Log.d("Status", "Connected");
                Toast.makeText(getBaseContext(), "Connected", Toast.LENGTH_LONG);

            }

    }


    private class ConnectedThread extends Thread {

        private final InputStream mmInStream;
        private final OutputStream mmOutStream;


        public ConnectedThread(BluetoothSocket  socket) {

            mmSocket = socket;

            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();

            } catch (IOException e) {

                e.printStackTrace();
            }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;

        }

        @Override
        public void run() {
            super.run();

            byte[] mmBuffer = new byte[1024];

            int mmBytes;


            //Start Listening

            while(true) {

                try {
                    mmBytes = mmInStream.read(mmBuffer);

                    Message readMsg = h.obtainMessage(handlerState, mmBytes, -1, mmBuffer);
                    readMsg.sendToTarget();


                } catch (IOException e){

                    e.printStackTrace();
                    Toast.makeText(getBaseContext(), "Input stream was disconnected", Toast.LENGTH_LONG).show();
                    break;

                }

            }
        }

        public void write(){

            try {
                mmSocket.getOutputStream().write("010C\r".getBytes());
            } catch (IOException e) {
                Log.e("Error", String.valueOf(e));
            }
        }
    }


    private class MyHandler extends Handler {

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            if (msg.what == handlerState) {

                Intent sendIntent = new Intent();

                byte[] rBuff = (byte[]) msg.obj; // recived message (bytes)

                String readMessage = new String(rBuff, 0, msg.arg1); // convert that message to string

                recDataString.append(readMessage);

                Log.d("Tab", String.valueOf(recDataString));

                int startOfIndex = recDataString.indexOf("41 0C");
                int stopIndex = recDataString.indexOf(">");

                if (stopIndex > 0) {

                    Log.d("RedVal", String.valueOf(recDataString));
                    String msg1 = String.valueOf(recDataString);

                    sendIntent.putExtra("SEND_MESSAGE", msg1);
                    sendIntent.setAction(MY_ACTION);
                    sendBroadcast(sendIntent);


                    recDataString.delete(0, recDataString.length());


                } else if(recDataString.length() > 33) {



                    String msg1 = String.valueOf(recDataString.substring(recDataString.length()-26, recDataString.length()));
                    sendIntent.putExtra("SEND_MESSAGE", msg1);
                    sendIntent.setAction(MY_ACTION);
                    sendBroadcast(sendIntent);
                    recDataString.delete(0, recDataString.length());
                }




            }

        }
    }

    class TimerDisplay extends TimerTask {

        @Override
        public void run() {
            HandlerDelay.postDelayed(new Runnable() {
                @Override
                public void run() {
                    mConncetedThread.write();
                }
            },500);
        }
    }




}

通过蓝牙连续发送字符串消息

1 个答案: