java - PC (Java) 和 Android 之间的蓝牙传输速度缓慢

Question

我不熟悉使用蓝牙。

引用 StackOverflow 上的一些讨论(我现在找不到链接)，我成功制作了一个小型 PC 服务器，通过蓝牙向 Android 智能手机发送字符串。

问题是传输速度极慢。对于像这样的字符串

ACLineStatus: Online

它们提供 6550 毫秒的实时信息。

如日志所示

E/time to execute code: 6452

D/prova: il dispositivo è: DESKTOP-U1VI1GB

D/prova: ACLineStatus: Online

如何提高传输速度？

这里是服务器代码(在 PC 上)

package hello;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import javax.bluetooth.*;
import javax.microedition.io.*;
/**
 * Class that implements an SPP Server which accepts single line of
 * message from an SPP client and sends a single line of response to the client.
 */

    //start server
    private void startServer() throws IOException {

        //Create a UUID for SPP
        UUID uuid = new UUID("1101", true);
        //Create the servicve url
        String connectionString = "btspp://localhost:" + uuid + ";name=Sample SPP Server";

        //open server url
        StreamConnectionNotifier streamConnNotifier = (StreamConnectionNotifier) Connector.open(connectionString);

        //Wait for client connection
        System.out.println("\nServer Started. Waiting for clients to connect...");
        StreamConnection connection = streamConnNotifier.acceptAndOpen();

        RemoteDevice dev = RemoteDevice.getRemoteDevice(connection);
        System.out.println("Remote device address: " + dev.getBluetoothAddress());
        System.out.println("Remote device name: " + dev.getFriendlyName(true));

        //read string from spp client
       /* InputStream inStream=connection.openInputStream();
        BufferedReader bReader=new BufferedReader(new InputStreamReader(inStream));
        String lineRead=bReader.readLine();
        System.out.println(lineRead);*/

        //send response to spp client
        OutputStream outStream = connection.openOutputStream();
        PrintWriter pWriter = new PrintWriter(new OutputStreamWriter(outStream));
        pWriter.write(SingletonBatteryStatus.getInstance().getBattery() + "\n");
        pWriter.flush();
        pWriter.close();

        streamConnNotifier.close();
    }


    public void run() {

        //display local device address and name
        LocalDevice localDevice = null;
        try {
            localDevice = LocalDevice.getLocalDevice();
            System.out.println("Address: " + localDevice.getBluetoothAddress());
            System.out.println("Name: " + localDevice.getFriendlyName());

            BluetoothSPPServer bluetoothSPPServer = new BluetoothSPPServer();
            bluetoothSPPServer.startServer();
        } catch (BluetoothStateException e) {
            System.out.println("non c'è il bluetooth");
            this.interrupt();
            // e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
            this.interrupt();
        }
    }
}

这里是客户端代码(Android 上)

package com.andrea.provabluetooth;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.UUID;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_ENABLE_BT = 1;
    private BluetoothAdapter btAdapter = null;
    private BluetoothSocket btSocket = null;
    private OutputStream outStream = null;
    private TextView out;

    // Well known SPP UUID
    private static final UUID MY_UUID =
            UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

    // Insert your server's MAC address
    private static String address = "3C:F8:62:50:AE:9B";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        out = (TextView) findViewById(R.id.textView);

        reciveMessage();
    }

    private void reciveMessage(){
        out.setText("Prova Bluetooth\n\n");


        btAdapter = BluetoothAdapter.getDefaultAdapter();

        CheckBTState();
        BluetoothDevice device = btAdapter.getRemoteDevice(address);

        // Two things are needed to make a connection:
        //   A MAC address, which we got above.
        //   A Service ID or UUID.  In this case we are using the
        //     UUID for SPP.
        try {
            btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
        } catch (IOException e) {
            AlertBox("1Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
        }

        // Discovery is resource intensive.  Make sure it isn't going on
        // when you attempt to connect and pass your message.
        btAdapter.cancelDiscovery();

        // Establish the connection.  This will block until it connects.
        try {
            btSocket.connect();
            out.append("\n...Connessione stabilita e data link aperto...");
        } catch (IOException e) {
            try {
                btSocket.close();
            } catch (IOException e2) {
                AlertBox("2Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + ".");
            }
        }

        InputStream inStream;
        try {
            inStream = btSocket.getInputStream();
            BufferedReader bReader = new BufferedReader(new InputStreamReader(inStream));
            long startTime = System.currentTimeMillis();
            String lineRead = bReader.readLine();
            long stopTime = System.currentTimeMillis();
            Log.e("time to execute code", stopTime - startTime + "");
            Log.d("prova", "il dispositivo è: " + device.getName());
            out.append("\n\n" + lineRead);
            Log.d("prova", lineRead);
        } catch (IOException e) {
            Log.d("prova", "il dispositivo non è: " + device.getName());
            //e.printStackTrace();
        }

        try {
            btSocket.close();
        } catch (IOException e2) {
            AlertBox("Fatal Error", "In onPause() and failed to close socket." + e2.getMessage() + ".");
        }
    }

    private void CheckBTState() {
        // Check for Bluetooth support and then check to make sure it is turned on

        // Emulator doesn't support Bluetooth and will return null
        if (btAdapter == null) {
            AlertBox("5Fatal Error", "Bluetooth Not supported. Aborting.");
        } else {
            if (btAdapter.isEnabled()) {
                out.append("\n...Bluetooth is enabled...");
            } else {
                //Prompt user to turn on Bluetooth
                Intent enableBtIntent = new Intent(btAdapter.ACTION_REQUEST_ENABLE);
                startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
            }
        }
    }

    public void AlertBox(String title, String message) {
        new AlertDialog.Builder(this)
                .setTitle(title)
                .setMessage(message + " Press OK to exit.")
                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface arg0, int arg1) {
                        finish();
                    }
                }).show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

另一个小问题:我没有更改 UUID，但我得到了它，因为我在 stackoverflow 上另一个问题的代码中找到了它。我可以保留它还是应该改变它？如果我必须改变它，我该怎么做？

感谢您的耐心等待

Answer 1

如果可以帮助某人，请不要关闭连接:大约 6 秒用于建立连接。如果您不关闭连接，下一篇文章将立即发送。