未创建Android蓝牙套接字连接

Question

我正在创建一个可以将数据发送到蓝牙设备的应用程序。我使用以下代码来创建和连接套接字：

package com.example.bluetooth;

import java.io.IOException;
import java.util.UUID;
import android.os.Bundle;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.util.Log;
import android.view.Menu;
import android.widget.Toast;

public class MainActivity extends Activity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        BluetoothAdapter ba = BluetoothAdapter.getDefaultAdapter();
        BluetoothDevice bd = ba.getRemoteDevice("20:13:10:15:39:84");
        Toast.makeText(getApplicationContext(), bd.getName(), Toast.LENGTH_SHORT).show();
        BluetoothSocket bs = null;
        try{
            bs = bd.createInsecureRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
        }
        catch(IOException io){
            Toast.makeText(getApplicationContext(), "Socket Create : " + io.toString() , Toast.LENGTH_SHORT).show();
        }
        try{
            ba.cancelDiscovery();
            bs.connect();
        }
        catch(IOException io){
            Log.e("Socket Connect", io.toString());
            Toast.makeText(getApplicationContext(), "Socket Connect : " + io.toString() , Toast.LENGTH_LONG).show();
        }
    }

}

我的问题是套接字没有连接。显示的消息是"java.io.IOException: JSR82 connect:连接未创建(失败或中止)“。

我使用的是android 4.2联想设备。

所用蓝牙模块为HC-05，微控制器为Arduino-Uno。

我也参考过类似的帖子，但都不能解决我的问题。

提前感谢

Answer 1

我首先重启了我的平板电脑，然后尝试使用我的代码连接蓝牙插座。我只需要使用：

public void onStop(){
    super.onStop();
    mSocket.close();
    mOutputStream.close();
 }

在最后。

啊，真灵!

问题是我从来没有尝试在结束时关闭套接字。

Answer 2

我使用了这段代码来稳定地连接到蓝牙设备(即蓝牙打印机)。现在它连接了10次中的9.9次，如果仍然发生一些错误，我会重新编程重置我的蓝牙，再次调用这段代码，然后它10次中连接10次。

public boolean connectToPrinter(String printerName) throws IOException 
    {
        BluetoothAdapter.getDefaultAdapter().cancelDiscovery();

        BluetoothDevice device = getPrinterByName(printerName);

        if (bluetoothSocket != null) 
        {
            bluetoothSocket.close();
        }


        try {

            Method m=device.getClass().getMethod("createRfcommSocket", new Class[]{int.class});
            bluetoothSocket=    (BluetoothSocket) m.invoke(device, 1);          

        } catch (Exception e) {
            e.printStackTrace();
        }


        if (bluetoothSocket == null)
            return false;

        bluetoothSocket.connect();

        return true;
    }

下面是getPrinterByName()的代码：

private BluetoothDevice getPrinterByName(String printerName) 
    {
        Set<BluetoothDevice> pairedDevices = BluetoothAdapter.getDefaultAdapter().getBondedDevices();

        for (BluetoothDevice device : pairedDevices) 
        {

            Log.e("","device name: "+device.getName());

            if (device.getName() == null)
                continue;
            if (device.getName().contains(printerName)) 
            {
                remoteDevice = device;
                //              pairPrinter(printerName);
                return remoteDevice;
            }
        }
        return null;
    }

Answer 3

首先从您的手机设置配对arduino蓝牙。然后尝试从你的应用程序连接到蓝牙。试试下面的代码：

    private BluetoothAdapter mBluetoothAdapter;
private BluetoothDevice mBluetoothDevice;
private BluetoothSocket mBluetoothSocket;
private UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

    try{

        if(mBluetoothAdapter == null){
            Log.d("bluetooth:", "device does not support bluetooth");
        }
        if(!mBluetoothAdapter.isEnabled()){
            Intent enableBt = new Intent(
                    BluetoothAdapter.ACTION_REQUEST_ENABLE);
            enableBt.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(enableBt);
        }

    }catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }

对于连接：

   mBluetoothDevice = mBluetoothAdapter.getRemoteDevice("xx:xx:xx:xx:xx:xx");
   try {
    mBluetoothSocket = mBluetoothDevice.createRfcommSocketToServiceRecord(uuid);
    mBluetoothSocket.connect();
    } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
    }