在asynctask中创建一个线程

Question

我在内部创建了MainActivity，我正在创建一个asynctask＆＃34; AsyncTask＆＃34;使用onPostExecute线程，我正在创建另一个名为＆＃34; RecvdOptimusData＆＃34;的线程。使用Android Studio。

public class optManControl extends AppCompatActivity {

    ....................

    // The Handler obtains the data from the Socket
    private final Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch(msg.what){
                case MSG_TYPE_BT_SENSOR: {
                    // Get the data from the msg.obj
                    String strReceived = null;
                    byte[] dataReceived = (byte[]) msg.obj;
                    if(dataReceived != null){
                        // construct a string from the valid bytes in the buffer
                        strReceived = new String(dataReceived, 0, msg.arg1);
                        if (strReceived != null) {
                            strReceived = trim(strReceived);
                            String[] values = split(strReceived, ',');
                            try {
                                msg("Setting Angle and Distance!");
                                imageDrawer.setAngle_Distance(values);
                            } catch (Exception e) {
                                msg("Angle-Distance Set Error");
                            }
                        }
                        else{
                            msg("Null str rcvd!!!");
                        }
                    }
                    else{
                        msg("Null data rcvd!!!");
                    }
                }
                break;
            }
        }
    };


..........................

我们创建最终线程RecvdOptimusData的线程

    private class ConnectBT extends AsyncTask<Void, Void, Void>  // UI thread
    {
        private boolean ConnectSuccess = true; //if it's here, it's almost connected

        @Override
        protected void onPreExecute() {
            alertView(R.string.title_dev_conn_progress);
            //progress = ProgressDialog.show(optManControl.this, "Connecting...", "Please wait!!!");  //show a progress dialog
        }

        @Override
        protected Void doInBackground(Void... devices) //while the progress dialog is shown, the connection is done in background
        {
            try {
                if (btSocket == null || !isBtConnected) {
                    myBluetooth = BluetoothAdapter.getDefaultAdapter();//get the mobile bluetooth device
                    BluetoothDevice dispositivo = myBluetooth.getRemoteDevice(address);//connects to the device's address and checks if it's available
                    btSocket = dispositivo.createInsecureRfcommSocketToServiceRecord(myUUID);//create a RFCOMM (SPP) connection
                    //btSocket = mConnectedSco.createScoSocket();//Create SCO socket connection using either "mConnectedSco" OR "dispositivo" objects.
                    BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
                    btSocket.connect();//start connection
                }
            } catch (IOException e) {
                ConnectSuccess = false;//if the try failed, you can check the exception here
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result) //after the doInBackground, it checks if everything went fine
        {
            super.onPostExecute(result);
            Looper.prepare();
            if (!ConnectSuccess) {
                msg("Connection Failed. Is it a SPP Bluetooth? Try again.");
                finish();
            } else {
                //Start new Thread to listen for data on BT port
                msg("Connected. Let's start a new Thread!!!");
                recvdOptimusData = new RecvdOptimusData();
                new Thread(recvdOptimusData).start();
                msg("Connected.!!!");
                isBtConnected = true;
            }
            //progress.dismiss();
            //dialog.create().dismiss();
            OptionDialog.dismiss();
        }
    }

以下是我们想要创建的新主题

    private class RecvdOptimusData implements Runnable{
        public void run() {
            byte[] buffer = new byte[1024]; // buffer to store the string
            int bytes; // Number of bytes read
            if (btSocket != null) {
                msg("BTsocket ! NULL");
                while (true) {
                    try {
                        msg("Reading Data from BT Socket sent by Optimus");
                        bytes = btSocket.getInputStream().read(buffer);
                        mHandler.obtainMessage(MSG_TYPE_BT_SENSOR, bytes, -1, buffer)
                                .sendToTarget();
                    } catch (IOException e) {
                        msg("BT Rcvd_Msg Read Error");
                    }
                }
            } else {
                msg("BTsocket NULL");
            }
        }
    }
}

堆栈跟踪

10-31 17:46:43.382 8727-8727/com.optimus.rccar E/AndroidRuntime: FATAL EXCEPTION: main
                                                                 Process: com.optimus.rccar, PID: 8727
                                                                 java.lang.RuntimeException: Only one Looper may be created per thread
                                                                     at android.os.Looper.prepare(Looper.java:89)
                                                                     at android.os.Looper.prepare(Looper.java:84)
                                                                     at com.optimus.rccar.optManControl$ConnectBT.onPostExecute(optManControl.java:286)
                                                                     at com.optimus.rccar.optManControl$ConnectBT.onPostExecute(optManControl.java:254)
                                                                     at android.os.AsyncTask.finish(AsyncTask.java:660)
                                                                     at android.os.AsyncTask.-wrap1(AsyncTask.java)
                                                                     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:677)
                                                                     at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                     at android.os.Looper.loop(Looper.java:154)
                                                                     at android.app.ActivityThread.main(ActivityThread.java:6317)
                                                                     at java.lang.reflect.Method.invoke(Native Method)
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:872)
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:762)